Showing posts with label carcinogenicity. Show all posts
Showing posts with label carcinogenicity. Show all posts

Monday, October 19, 2026

International Agency for Research on Cancer (WHO) Position on Radiofrequency Radiation



The Collegium Ramazzini is an independent, international scientific academy comprised of 180 physicians and scientists from 45 countries. Its mission is to increase scientific knowledge of the environmental and occupational causes of disease and to transmit this knowledge to decision-makers, the media and the global public in order to prevent disease, promote good health and save lives. The Collegium Ramazzini is independent of commercial interests. It advances scientifically based solutions to global problems in occupational and environmental health.

The purpose of this statement is to call attention to emerging studies that have added significantly to appreciating and understanding the capacity of exposures to radio frequency electromagnetic fields (RF EMF) to cause or contribute to human cancers, and to call on the International Agency for Research on Cancer (IARC) to re-evaluate RF EMF, as recommended with high priority by recent Advisory Groups to Recommend Priorities for the IARC Monographs during 2020-2024 and 2025-2029 (IARC 2024).

In 2011 IARC convened a Working Group to evaluate the scientific evidence concerning the carcinogenic hazard of RF EMF to humans (IARC 2013). This portion of the electromagnetic spectrum, ranging from 30 kHz to 300 GHz, is used in wireless telecommunication primarily but not exclusively in mobile phones. The epidemiologic evidence evaluated by the Working Group came from time-trend, cohort, and case-control studies of populations exposed in occupational settings, from sources in the general environment and from use of mobile and cordless phones, with the most informative studies (Interphone and studies from Sweden) focused on brain tumors associated with mobile phone use. The Working Group also evaluated experimental evidence from numerous animal cancer studies employing various frequencies, exposure modalities and durations, as well as studies of mechanistic end points potentially related to cancer including genotoxicity, immune function, cell signaling, oxidative stress and others.

The overall evaluation of the Working Group was that radiofrequency electromagnetic fields are possibly carcinogenic to humans (Group 2B) based on the findings from epidemiology studies, which were concluded to provide “limited evidence” for gliomas and acoustic neuromas. The data from experimental animal studies including standard 2-year rodent cancer bioassays, tumor-prone animal models, initiation-promotion, or cocarcinogenesis studies were considered “limited evidence” of carcinogenicity, and evidence of supporting mechanisms was weak (IARC 2013).

Subsequent to the IARC review, new findings from two comprehensive standard animal cancer bioassays, additional novel mechanistic findings and a recent World Health Organization (WHO)-sponsored systematic review of animal cancer findings have been published. In 2016 the US National Toxicology Program released initial findings (with final reports in 2018) from 2-year rodent cancer studies of GSM and CDMA modulated RFR in rats (900 MHz, 0, 1, 3 or 6 W/kg) and mice (1900 MHz 0, 2.5, 5, 10 W/kg), reporting clear evidence in male and female rats of malignant schwannomas of the heart, evidence of malignant gliomas of the brain, and some evidence of DNA damage in the hippocampus of male rats (Wyde et al. 2016; NTP 2018a, 2018b). Also in 2018, the Ramazzini Institute reported findings from their lifespan rodent cancer studies in which rats were exposed to 1,800 MHz GSM far field RF EMF at much lower power levels of 0, 5, 25 or 50 V/m (~ 0, 0.001, 0.03, 0.1 W/kg). Increased heart schwannomas were observed in male rats, and a non-significant increase in brain malignant glial cell tumors was observed in females (Falcioni et al., 2018). In both studies the cell types responding to RF EMF were morphologically similar to those observed in the human epidemiology studies cited above (brain malignant gliomas; heart schwannomas and acoustic neuromas). Lastly in a collaborative study between the NTP and Ramazzini Institute, gliomas and schwannomas from rats in the Ramazzini study were analyzed for single nucleotide variants and small insertions and deletions in genes analogous to genes recognized to be mutated in human glial tumors. Remarkably, not only were similar genetic alterations found in the rat tumors with human glial cell tumors as reported in the Catalogue of Somatic Mutations in Cancer (COSMIC) database, but also alterations in many of these same genes were observed in glial tissues from the Ramazzini RFR-exposed rats collected after only one year of exposure, and not in controls, well before when tumors developed in the exposed rats (Brooks et al, 2024).

In May of 2025 a systematic review of experimental animal cancer studies on RF EMF (Mevissen et al. 2025) was published as part of a larger series of systematic reviews to inform a health risk assessment of RF EMF sponsored by the WHO. Fifty-two studies were evaluated including 20 chronic cancer bioassays. The Mevissen et al. review concluded that there was high confidence in the evidence linking RF EMF exposures with schwannomas of the heart and moderate to high confidence in the link with gliomas of the brain in rats. Moderate confidence was also concluded for increases in adrenal gland neoplasms in rats and lymphomas, lung and liver neoplasms in mice exposed to RF EMF. Surprisingly, the organizers and the editors of the WHO systematic review series criticized this systematic review… “one notable exception was the systematic review on the effects of RF EMF on cancer in experimental animals, which stood out due to its use of a different synthesis method” and “whether this method proves valid – and whether alternative synthesis approaches would yield the same conclusion – remains to be seen” (Verbeek 2025). On the contrary, the International Commission on the Biological Effects of Electromagnetic Fields (ICBE-EMF) pointed out a number of methodological flaws and weaknesses in the conduct of the other WHO systematic reviews, including concerns related to conflict of interests of many authors of the series, but “endorsed the methods and conclusions of the animal cancer SR,” (Melnick et al. 2025). Indeed, the controversy over the WHO systematic review for RF EMF health risk assessment highlights the essential role of the cancer hazard evaluations performed by the IARC Monographs, which are based on an up-to-date and fit-for purpose methodology for cancer hazard identification and are free from conflict of interests (IARC 2019). Indeed, a solid hazard assessment should be the first step and should be done prior to any attempt to perform risk estimates.

The Collegium Ramazzini therefore emphasizes, considering the new evidence, the urgent need to re-evaluate radiofrequency cancer hazard by IARC and that any risk assessment by WHO should be based on a cancer hazard evaluation by IARC.

References

Brooks AM, Vornoli A, Kovi RC, Ton TVT, Xu M, Mashal A, et al. (2024). Genetic profiling of rat gliomas and cardiac schwannomas from life-time radiofrequency radiation exposure study using a targeted next-generation sequencing gene panel. PLoS One. 19(1):e0296699. https://doi.org/10.1371/journal.pone.0296699

Falcioni L, Bua L, Tibaldi E, Lauriola M, De Angelis L, Gnudi F, et al. (2018). Report of final results regarding brain and heart tumors in Sprague-Dawley rats exposed from prenatal life until natural death to mobile phone radiofrequency field representative of a 1.8 GHz GSM base station environmental emission. Environ Res. 165:496–503. https://doi.org/10.1016/j.envres.2018.01.037 PMID:29530389

IARC (2013). Non-ionizing radiation, Part 2: Radiofrequency electromagnetic fields. IARC Monogr Eval Carcinog Risks Hum. 102:1–462. https://publications.iarc.fr/126 PMID:24772662

IARC (2019). Preamble. International Agency for Research on Cancer, Lyon, Fr.

IARC (2024). Report of the Advisory Group to Recommend Priorities for the IARC Monographs during 2025–2029. International Agency for Research on Cancer, Lyon, Fr.

Melnick RL, Moskowitz JM, Héroux P, Mallery-Blythe E, McCredden JE, Herbert M, Hardell L, Philips A, Belpoggi F, Frank JW, Scarato T, Kelley E; International Commission on the Biological Effects of Electromagnetic Fields (ICBE-EMF). The WHO-commissioned systematic reviews on health effects of radiofrequency radiation provide no assurance of safety. Environ Health. 2025 Oct 2;24(1):70. doi: 10.1186/s12940-025-01220-4. PMID: 41034851; PMCID: PMC12490090.

Mevissen M, Ducray A, Ward JM, Kopp-Schneider A, McNamee JP, Wood AW, Rivero TM, Straif K (2025). Effects of radiofrequency electromagnetic field exposure on cancer in laboratory animal studies, a systematic review. Environ. Inter. 199: 109482. https://doi.org/10.1016/j.envint.2025.109486

NTP (2018a). Toxicology and carcinogenesis studies in B6C3F1/N mice exposed to whole-body radio frequency radiation at a frequency (1900 MHz) and modulations (GSM and CDMA) used by cell phones. Natl Toxicol Program Tech Rep Ser. 596. Research Triangle Park (NC), USA: National Toxicology Program, National Institutes of Health. https://ntp.niehs.nih.gov/ntp/htdocs/lt_rpts/tr596_508.pdf

NTP (2018b). Toxicology and carcinogenesis studies in Hsd:Sprague Dawley SD rats exposed to whole-body radiofrequency radiation at a frequency (900 MHz) and modulations (GSM and CDMA) used by cellphones. Natl Toxicol Program Tech Rep Ser. 595: NTP-TR-595 Research Triangle Park (NC), USA: National toxicology Program, National Institutes of Health. https://www.niehs.nih.gov/ntp-temp/tr595_508.pdf

Verbeek J, Zeeb H, van Deventer E, Ijaz S, Doré JF, Driessen S, Roth N, Whaley P. Systematic reviews and meta-analyses for the WHO assessment of health effects of exposure to radiofrequency electromagnetic fields, an introduction. Environ Int. 2025 Sep; 203:109751. doi: 10.1016/j.envint.2025.109751. Epub 2025 Aug 27. PMID: 40897550.

Wyde M, Cesta M, Blystone C, Elmore S, Foster P, Hooth M, Kissling G, Malarkey D, Sills R, Stout M, Walker N, Witt K, Wolfe M, and Bucher J (2016). Report of Partial findings from the National Toxicology Program Carcinogenesis Studies of Cell Phone Radiofrequency Radiation in Hsd: Sprague Dawley® SD rats (Whole Body Exposure). bioRxiv doi: https://doi.org/10.1101/055699


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Report of the Advisory Group to Recommend Priorities for the IARC Monographs during 2025–2029 

Radiofrequency electromagnetic fields including wireless mobile radiation (pp. 171-173)

Current IARC/WHO classification

Radiofrequency electromagnetic field (RF-EMF) radiation (including from wireless mobile telephones) has been previously classified by IARC as possibly carcinogenic to humans (Group 2B) in IARC Monographs Volume 102 in 2011 (IARC, 2013a), based on limited evidence in humans for glioma and acoustic neuroma. RF-EMF was given a priority rating of high by the Advisory Group to Recommend Priorities for the IARC Monographs during 2020–2024 (IARC, 2019a), on the basis of new cancer bioassay evidence in two independent studies (described below).

WHO is undertaking a health risk assessment of RF-EMF for a variety of outcomes, including cancer. This will be published as a monograph in the Environmental Health Criteria series and is based on several, currently ongoing, systematic reviews commissioned by WHO (Lagorio et al., 2021; Mevissen et al., 2022).

Exposure characterization

In IARC Monographs Volume 102, RF-EMF radiation was defined as radiation in the frequency range 30 kHz to 300 GHz (IARC, 2013a). Exposure occurs in the general population and in occupational settings, with sources including mobile phones, wireless network, television, radio, 5G technologies, Bluetooth, microwaves, cooking hobs, industrial heating of materials, radar, anti-theft devices, and MRI (IARC, 2013a). Exposure to mobile phones is ubiquitous, considering that nearly 95% of the population in high-income countries and 49% in low-income countries own a mobile phone (International Telecommunications Union, 2022). Source-exposure matrices for the general population and workers are available (Vila et al., 2016; van Wel et al., 2021).

Cancer in humans


The 2019 Advisory Group report (IARC, 2019a) indicated that results from epidemiological studies published after IARC Monographs Volume 102 were mixed (Benson et al., 2013; Hardell et al., 2013; Coureau et al., 2014; IARC, 2019a; Röösli et al., 2019). Since the 2019 Advisory Group report (IARC, 2019a), results from the MOBI-Kids study, an international study of brain cancer and the use of EMF technology by children and adolescents (Castaño-Vinyals et al., 2022), the update of the UK Million Women Study (Schüz et al., 2022), and the European Cohort Study of Mobile Phone Use and Health (COSMOS) (Feychting et al., 2024) were published. No increased risk of neuroepithelial brain tumour was found in the MOBI-Kids study (Castaño-Vinyals et al., 2022). In the Million Women Study update, the increased risk for acoustic neuroma reported previously (10+ years use versus never, RR, 2.46; 95% CI, 1.07–5.64) (Benson et al., 2013) was attenuated (10+ years use versus never, RR, 1.32; 95% CI, 0.89–1.96), and no increased risk was found for other cancer subtypes (glioma, glioblastoma, pituitary, eye tumour); however, the exposure assessment was crude. The previous analysis (Benson et al., 2013) reported Ptrend = 0.03 for acoustic neuroma by duration of use, but such an analysis was not reported in the updated publication (Schüz et al., 2022). COSMOS followed 264 574 participants for a median of 7.12 years (recruitment, 2007–2012, in Denmark, Finland, the Netherlands, Sweden, and the UK). For 100 regression-calibrated cumulative hours of calls (country-specific regression-calibrated estimates based on data collected from operators were applied to the self-reported measurements), HRs were 1.00 (95% CI, 0.98–1.02) for glioma, 1.01 (95% CI, 0.96–1.06) for meningioma, and 1.02 (95% CI, 0.99–1.06) for acoustic neuroma (Feychting et al., 2024).

Mobile phone use was associated with increases in overall cancer and NMSC, urinary cancer (in men only), prostate cancer, and vulva cancer, but not brain cancer, in the UK Biobank cohort (Zhang et al., 2024). There was also a significant trend by length of use for NMSC and prostate cancer (Zhang et al., 2024) Concern exists over exposure misclassification, as mobile phone use was captured only at baseline. These findings are not consistent with those of a Danish nationwide cohort study (Schüz et al., 2006).

In IARC Monographs Volume 102 (IARC, 2013a), selection bias and recall bias from case–control studies were noted as being of major concern. Bias analysis available at the time of that evaluation showed that the J-shaped response curve observed in the Interphone study, the largest case–control study on mobile phone use contributing to the evidence published in IARC Monographs Volume 102 (IARC, 2013a), could have been explained by selection bias, leading to underrepresentation of unexposed controls (Vrijheid et al., 2009a). A recent bias analysis using Monte Carlo simulations showed that the J-shaped relation observed in the Interphone study was compatible with a scenario of greater systematic (> 10%) and random error in cases compared with controls, in the absence of any effect (Bouaoun et al., 2024). Validation studies within the Interphone study showed that there was little differential exposure misclassification between cases and controls; however, in heavy users, overestimation was greater in cases than in controls (Vrijheid et al., 2009b).

Cancer in experimental animals

The 2019 Advisory Group report (IARC, 2019a) noted the availability of new data from the large US NTP study that show clear evidence of an increased incidence of malignant schwannoma in the heart (and possibly some evidence of malignant glioma in the brain) in male rats exposed to radiofrequency radiation at frequencies used by mobile phones; however, no clear increased risk was seen in female rats. Some equivocal evidence was observed of increased evidence of malignant glioma in the brain, malignant schwannoma in the heart, and pheochromocytoma in the adrenal medulla (NTP, 2018a, b). An increased risk of schwannoma of the heart observed in male rats exposed to the highest dose was found in an experimental study conducted at the Ramazzini Institute (Falcioni et al., 2018). International studies, aimed to verify the NTP studies, are ongoing in Japan and the Republic of Korea and are expected in 2024 (Ahn et al., 2022). Currently, a systematic review of the effects of RF-EMF on cancer laboratory animals is ongoing as part of a WHO risk assessment project (Mevissen et al., 2022).

Mechanistic evidence

As noted in the 2019 Advisory Group report (IARC, 2019a): “The previous IARC evaluation concluded that there was weak evidence that radiofrequency radiation was genotoxic but that there was no evidence for mutagenicity (IARC, 2013a).” Since then, there have been many new publications on the genotoxicity of RF-EMF radiation, including studies in exposed humans. The formation of micronuclei on buccal mucosal cells was shown in several studies on mobile phone-emitted radiation (Rashmi et al., 2020; Revanth et al., 2020). Other studies found no evidence of micronucleus formation (de Oliveira et al., 2017) or no conclusive evidence for induction of DNA damage or for alterations of the DNA repair capacity in human cells exposed to several frequencies of RF-EMF radiation (Schuermann et al., 2020). In other studies, no effects of RF-EMF exposure on oxidant or antioxidant capacity, apoptosis, or mutations in the TP53 gene were revealed, regardless of the frequency (Khalil et al., 2014; Gulati et al., 2020). The authors of a meta-analysis to investigate whether RF-EMF emitted by mobile phones have genotoxic or cytotoxic effects on the oral epithelium concluded that the evidence for genotoxic effects was weak (Dos Santos et al., 2020). In experimental systems, there is a large body of literature on investigations of the genotoxicity of RF-EMF (Meltz, 2003). A study showed that rat gliomas appear to share some genetic alterations with IDH1 wildtype human gliomas, and rat cardiac schwannomas also harbour mutations in some of the queried cancer genes (Brooks et al., 2024). An independent systematic review of the genotoxicity of RF-EMF in in vitro mammalian models is ongoing (Romeo et al., 2021).

In addition, evidence associated with other KCs is available. For example, chronic exposure to RF-EMF emitted from mobile phones may induce oxidative stress and an inflammatory response in rats (Singh et al., 2020). Currently, a systematic review of the effects of RF-EMF on biomarkers of oxidative stress in vivo and in vitro is ongoing as part of the WHO risk assessment project (Henschenmacher et al., 2022). Several studies have investigated the immunotoxicity of RF-EMF (Yadav et al., 2022). Mobile phone radiofrequency radiation was found to be associated with thyroid gland insufficiency and alterations in serum thyroid hormone levels in exposed humans and in rodents, with a possible disruption in the hypothalamic–pituitary–thyroid axis (Alkayyali et al., 2021).

Summary

Since the last evaluation, there have been several new high-quality studies. Overall, the human cancer evidence is mixed. There is new evidence of carcinogenicity in experimental animals. Since the previous evaluation, there is new mechanistic evidence related to the KCs, especially genotoxicity in experimental systems and in exposed humans. However, several of the genotoxicity studies in exposed humans provided inconsistent results. Thus, the mechanistic available evidence currently available may be inconclusive.

Overall, the new evidence regarding cancer in humans and in experimental animals could support a re-evaluation, although a change in the current classification of the carcinogenicity of RF-EMF is uncertain. The Advisory Group therefore considered an IARC Monographs evaluation of RF-EMF to be warranted but suggests an evaluation in the latter half of the next 5 years, to await the results of ongoing cancer bioassays, which may provide additional mechanistic evidence.

Recommendation: High priority (and ready for evaluation within 5 years)

Open access report:

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In March, 2019, the Advisory Group for the IARC recommended that the IARC review the research on RFR to determine if it is a carcinogenic hazard (i.e. Group 2A or Group 1). The advisory group recommended that this review be conducted within the next five years and called it a "high priority."

Following are excerpts from the IARC report:

International Agency for Research on Cancer (IARC). Report of the Advisory Group to Recommend Priorities for the IARC Monographs during 2020–2024. IARC, World Health Organization, 2019. https://monographs.iarc.fr/wp-content/uploads/2019/10/IARCMonographs-AGReport-Priorities_2020-2024.pdf.


Report of the Advisory Group to Recommend Priorities for the IARC Monographs during 2020–2024

Introduction (pp. 1-2)

"An IARC Advisory Group to Recommend Priorities for the IARC Monographs during 2020–2024 met in Lyon, France, on 25–27 March 2019. IARC periodically convenes such Advisory Groups to ensure that the Monographs evaluations reflect the current state of scientific evidence relevant to carcinogenicity.

Before the meeting, IARC solicited nominations of agents via the website of the IARC Monographs programme and the IARC RSS news feed, and through direct contact with the IARC Governing Council and members of the IARC Scientific Council, WHO headquarters and regional offices, and previous participants in the Monographs programme. Nominations were also developed by IARC personnel, including the recommended priorities remaining from a similar Advisory Group meeting convened in 2014 (Straif et al., 2014), and the priorities nominated by the Advisory Group.

The list of Advisory Group members and all other meeting participants is provided in Annex 1 (see https://monographs.iarc.fr/wp-content/uploads/2019/02/AGP-ListofParticipants.pdf ) ...."

"Priority was assigned on the basis of (i) evidence of human exposure and (ii) the extent of the available evidence for evaluating carcinogenicity (i.e. the availability of relevant evidence on cancer in humans, cancer in experimental animals, and mechanisms of carcinogenesis to support a new or updated evaluation according to the Preamble to the IARC Monographs). Any of the three evidence streams could alone support prioritization of agents with no previous evaluation. For previously evaluated agents, the Advisory Group considered the basis of the previous classification as well as the potential impact of the newly available evidence during integration across streams (see Table 4 in the Preamble to the IARC Monographs). Agents without evidence of human exposure or evidence for evaluating carcinogenicity were not recommended for further consideration."

....

"Non-ionizing radiation (radiofrequency) and extremely low-frequency magnetic fields (pp. 148-149)

Radiofrequency electromagnetic fields (RF-EMF) were evaluated by the IARC Monographs as possibly carcinogenic to humans (Group 2B) (IARC, 2013e), on the basis of limited evidence of an increased risk of glioma. Extremely low-frequency magnetic fields (ELF-MF) were evaluated as possibly carcinogenic to humans (Group 2B) (IARC, 2002), on the basis of limited evidence of an increased risk of childhood leukaemia.

Exposure Data

Human exposures to RF-EMF can occur from use of personal devices (e.g. cell phones, cordless phones, and Bluetooth) and from environmental sources such as cell phone base stations, broadcast antennas, and medical applications. More than 5 billion people now have access to cell phone devices, and the technology is constantly evolving. Use has also expanded rapidly in low- and middle-income countries, where more than 75% of adults now report owning a cell phone; in high-income countries, the proportion is 96% (Pew Research Center, 2018).

Cancer in Humans

Since the previous IARC Monographs evaluation, several new epidemiological studies have been published on the association between RF-EMF and cancer, although the evidence remains mixed. In the Million Women Study cohort, there was no evidence of increased risk of glioma or meningioma, even among long-term users. There was an increased risk of acoustic neuromas with long-term use and a significant dose–response relationship (Benson et al., 2013). Updated follow-up in the Danish nationwide subscribers study did not find increased risks of glioma, meningioma, or vestibular schwannoma, even among those with subscriptions of 10 years or longer (Frei et al., 2011; Schüz et al., 2011). New reports from case–control studies that assessed long-term use also found mixed results; for example, increased risks of glioma and acoustic neuroma were reported by Hardell & Carlberg (2015) and Hardell et al. (2013), but no evidence of increased risks for these tumours were reported by Yoon et al. (2015) and Pettersson et al. (2014). Röösli et al. (2019) recently reviewed these new data. Several large-scale studies are still in progress and should report results within the next few years. Mobi-Kids is a multicentre case–control study of brain tumours in those aged 10–24 years. Cohort Study of Mobile Phone Use and Health (COSMOS) is a new European cohort of adult cell phone users. There will also be updated results from the Million Women Study.

Cancer in Experimental Animals

New data in experimental animals for exposure to RF-EMF have been published since the previous IARC Monographs evaluation. The large study by the United States National Toxicology Program found an increased risk of malignant schwannomas of the heart in male rats with high exposure to radiofrequency radiation at frequencies used by cell phones, as well as possible increased risks of certain types of tumours in the brain and adrenal glands, but no increased risks in mice or female rats (NTP, 2018a, b). Another study in experimental animals also found an increase in schwannomas of the heart in highly exposed male rats and a possible increase in gliomas in female rats (Falcioni et al., 2018).

 Mechanistic Evidence

The previous IARC evaluation concluded that there was weak evidence that radiofrequency radiation was genotoxic but that there was no evidence for mutagenicity (IARC, 2013e). Although there have been many new publications from a wide variety of experiments, uncertainty remains about the mechanisms, and there are few systematic reviews of the new data (Kocaman et al., 2018).

Although a future evaluation could be broadened to consider exposure to all non-ionizing radiation (including ELF-MF), ELF-MF were evaluated by IARC as possibly carcinogenic to humans (Group 2B), and the Advisory Group did not recommend an update, because of a lack of new informative epidemiological findings, no toxicological evidence, and little supporting mechanistic evidence.

References

The following key references were also identified: Coureau et al. (2014); Carlberg & Hardell (2015); Pedersen et al. (2017).

Recommendation for non-ionizing radiation (radiofrequency): High priority (and ready for evaluation within 5 years)

Recommendation for extremely low-frequency magnetic fields: No evaluation "

References cited in this section of the report:

Benson VS, Pirie K, Schüz J, Reeves GK, Beral V, Green J; Million Women Study Collaborators (2013). Mobile phone use and risk of brain neoplasms and other cancers: prospective study. Int J Epidemiol. 42(3):792–802. https://doi.org/10.1093/ije/dyt072 PMID:23657200

Carlberg M, Hardell L (2015). Pooled analysis of Swedish case-control studies during 1997-2003 and 2007-2009 on meningioma risk associated with the use of mobile and cordless phones. Oncol Rep. 33(6):3093–8. https://doi.org/10.3892/or.2015.3930 PMID:25963528

Coureau G, Bouvier G, Lebailly P, Fabbro-Peray P, Gruber A, Leffondre K, et al. (2014). Mobile phone use and brain tumours in the CERENAT case-control study. Occup Environ Med. 71(7):514–22. https://doi.org/10.1136/oemed-2013-101754 PMID:24816517

Falcioni L, Bua L, Tibaldi E, Lauriola M, De Angelis L, Gnudi F, et al. (2018). Report of final results regarding brain and heart tumors in Sprague-Dawley rats exposed from prenatal life until natural death to mobile phone radiofrequency field representative of a 1.8 GHz GSM base station environmental

Frei P, Poulsen AH, Johansen C, Olsen JH, Steding-JessenM, Schüz J (2011). Use of mobile phones and risk of brain tumours: update of Danish cohort study. BMJ. 343:d6387. https://doi.org/10.1136/bmj.d6387 PMID:22016439

Hardell L, Carlberg M (2015). Mobile phone and cordless phone use and the risk for glioma - analysis of pooled case-control studies in Sweden, 1997-2003 and 2007-2009. Pathophysiology. 22(1):1–13. https://doi.org/10.1016/j.pathophys.2014.10.001 PMID:25466607

IARC (2013e). Non-ionizing radiation, Part 2: Radiofrequency electromagnetic fields. IARC Monogr Eval Carcinog Risks Hum. 102:1–460. Available from: http://publications.iarc.fr/126 PMID:24772662

Kocaman A, Altun G, Kaplan AA, Deniz ÖG, Yurt KK, Kaplan S (2018). Genotoxic and carcinogenic effects of non-ionizing electromagnetic fields. Environ Res. 163:71–9. https://doi.org/10.1016/j.envres.2018.01.034 PMID:29427953

NTP (2018a). Toxicology and carcinogenesis studies in B6C3F1/N mice exposed to whole-body radio frequency radiation at a frequency (1900 MHz) and modulations (GSM and CDMA) used by cell phones. Natl Toxicol Program Tech Rep Ser. 596. Research Triangle Park (NC), USA: US Department of Health and Human Services, Public Health Service. Available from: https://ntp.niehs.nih.gov/ntp/htdocs/lt_rpts/tr596_508.pdf.

NTP (2018b). Toxicology and carcinogenesis studies in Hsd:Sprague Dawley SD rats exposed to whole-body radiofrequency radiation at a frequency (900MHz) and modulations (GSM and CDMA) used by cellphones. Natl Toxicol Program Tech Rep Ser. 595. Research Triangle Park (NC), USA: US Department of Health and Human Services, Public Health Service. Available from: https://www.niehs.nih.gov/ntp-temp/tr595_508.pdf.

Pedersen C, Poulsen AH, Rod NH, Frei P, Hansen J, Grell K, et al. (2017). Occupational exposure to extremely low-frequency magnetic fields and risk for central nervous system disease: an update of a Danish cohort study among utility workers. Int Arch Occup Environ Health. 90(7):619–28. https://doi.org/10.1007/s00420-017-1224-0 PMID:28429106

Pettersson D, Mathiesen T, Prochazka M, Bergenheim T, Florentzson R, Harder H, et al. (2014). Long-term mobile phone use and acoustic neuroma risk. Epidemiology. 25(2):233–41. https://doi.org/10.1097/EDE.0000000000000058 PMID:24434752

Pew Research Center (2018). Social media use continues to rise in developing countries, but plateaus across developed ones. Available from: https://www.pewglobal.org/2018/06/19/social-media-use-continues-to-rise-in-developing-countries-but-plateaus-across-developed-ones/

Schüz J, Steding-JessenM, Hansen S, Stangerup SE, Cayé-Thomasen P, Poulsen AH, et al. (2011). Long-term mobile phone use and the risk of vestibular schwannoma: a Danish nationwide cohort study. Am J Epidemiol. 174(4):416–22. https://doi.org/10.1093/aje/kwr112 PMID:21712479

Straif K, Loomis D, Guyton K, Grosse Y, Lauby-Secretan B, El Ghissassi F, et al. (2014). Future priorities for the IARC Monographs. Lancet Oncol. 15(7):683–4. https://doi.org/10.1016/S1470-2045(14)70168-8

Yoon S, Choi J-W, Lee E, An H, Choi HD, KimN (2015). Mobile phone use and risk of glioma: a case-control study in Korea for 2002-2007. Environ Health Toxicol. 30:e2015015. https://doi.org/10.5620/eht.e2015015 PMID:26726040

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In May, 2011, the International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization, classified radio frequency radiation (RFR) as "possibly carcinogenic to humans (Group 2B), based on an increased risk for glioma, a malignant type of brain cancer, associated with wireless phone use." "The conclusion means that there could be some risk, and therefore we need to keep a close watch for a link between cell phones and cancer risk."

A working group of 31 scientists from 14 nations made this determination after reviewing hundreds of studies that examined the potential carcinogenic hazard of long-term exposure to RFR. They examined exposure data, studies of cancer in humans, studies of cancer in experimental animals, and mechanistic and other relevant data. 

" 'Given the potential consequences for public health of this classification and findings,' said IARC Director Christopher Wild, 'it is important that additional research be conducted into the long‐term, heavy use of mobile phones. Pending the availability of such information, it is important to take pragmatic measures to reduce exposure such as hands‐free devices or texting.' "


IARC (2011). "IARC classifies radiofrequency electromagnetic fields as possibly carcinogenic to humans." Press Release No. 208. IARC, WHO. https://www.iarc.fr/wp-content/uploads/2018/07/pr208_E.pdf

IARC (2013e). Non-ionizing radiation, Part 2: Radiofrequency electromagnetic fields. IARC Monogr Eval Carcinog Risks Hum. 102:1–460. Available from: http://publications.iarc.fr/126 PMID:24772662

For a summary of this 2013 monograph see:

Tuesday, August 11, 2026

NTP Cellphone Carcinogenicity Study: Followup Studies

Flawed "Validation" Studies Do Not Negate Established Evidence 
That Cell Phone Radiation Causes Cancer in Rats

Summary: A new paper published in Environmental Health finds that the Japanese and Korean cell phone radiation cancer studies do not prove cell phone safety, as they were underpowered and used too few exposure doses to legitimately challenge the U.S. National Toxicology Program’s landmark findings of increased cancer from long-term cell phone radiation exposure. Long-overdue policy changes to reduce public exposure are urgently needed.

A new peer reviewed paper published in the journal Environmental Health states that two industry-linked “validation” studies from Japan and Korea published in 2026, designed to verify the U.S. National Toxicology Program’s (NTP) finding that cell phone radiofrequency (RF) radiation causes cancer in rats, were so underpowered and narrowly designed such that they could never have confirmed or refuted the original results, regardless of the outcome. The authors state that these “validation” studies should not comfort the public when it comes to the safety of cell phones and other wireless devices.

The paper “Conflicting views in experimental carcinogenesis: A commentary on design and methodological deficiencies in the follow-up validation studies on radiofrequency radiation,” authored by Ronald L. Melnick (formerly of the National Institute of Environmental Health Sciences), Joel M. Moskowitz (University of California, Berkeley), and Paul Héroux (McGill University) on behalf of the International Commission on the Biological Effects of Electromagnetic Fields (ICBE-EMF), examines the design and interpretation of the Japan and Korea studies against long-standing scientific and regulatory standards for animal carcinogenicity testing.

Background

In 2011, the World Health Organization’s International Agency for Research on Cancer (IARC) classified RF radiation as “possibly carcinogenic to humans,” based largely on results from human epidemiological studies. In 2018, the National Toxicology Program, which is part of the U.S. Department of Health and Human Services, issued the final report of their $30 million animal studies concluding there is “clear evidence” that male rats exposed to cell phone (RF) radiation for two years developed malignant heart schwannomas, a rare tumor, along with “some evidence” of brain gliomas and adrenal tumors. The NTP study was designed to provide greater sensitivity than international guidelines for rigorous cancer-testing.

A study conducted by the Ramazzini Institute in 2018 reported increased tumors similar to those observed in the NTP. These new animal cancer findings, along with additional human studies, prompted the WHO/IARC advisory group to repeatedly recommend a new evaluation of the scientific evidence on the carcinogenicity of wireless radiation. Many scientists with expertise in environmental carcinogenicity then published their conclusion that the current evidence is now consistent with IARC criteria for the classification of wireless RF radiation as a “probable human carcinogen”  (IARC Group 2A), or even  “carcinogenic to humans” (Group 1).

However, after the NTP study was released, new animal studies were launched in Japan and Korea, under an “International Validation Project,” aiming to test whether the NTP’s findings were reproducible. Their results, separately published in 2026, concluded that long-term RF radiation exposure did not produce reproducible carcinogenic or genotoxic effects.

However, according to the new paper, the Japanese and Korean animal studies did not replicate the NTP study and had several deficiencies, including:

  • Severely Reduced Statistical Power: The follow-up studies used only 70 animals per group, compared to 90 per group in the NTP study. Power calculations indicate that detecting a significant response for rare tumors at the lower exposure level used in those studies would require many more animals per group.
  • Omission of High-Dose Groups: The follow-up studies tested only a single exposure level (4 W/kg) and dropped the NTP’s highest exposure level (6 W/kg), where significant carcinogenic effects were most statistically pronounced.
  • Violation of FDA and the Organization for Economic Co-operation and Development Guidelines: Testing guidelines by these groups require at least three different doses plus a control group to conduct a critical dose-response trend analysis. Single-dose studies eliminate the ability to detect dose-dependent trends.
  • Overlooked Signals of Harm: Despite being underpowered, the Korean study actually observed a 3% incidence rate of heart schwannomas in exposed rats (versus 0% in controls), matching the tumor rate observed at 3 W/kg in the NTP study, yet the researchers surprisingly dismissed the finding.
  • Prominent Role of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and Industry-Friendly Advisors: The project’s principal investigator was an ICNIRP member, and the advisory committee overseeing the research was heavily composed of current and former ICNIRP members, several of whom have served as industry consultants. The Japan/Korea studies were aimed at protecting ICNIRP’s current cell phone radiation safety limits rather than at documenting radiation risks.

The authors of the new analysis conclude that the Japan and Korea studies’ conclusion of “no reproducible carcinogenic potential” of cell phone radiation is simply not supported by the studies’ design and, in the case of the Korean study, is undercut by its own data. Therefore, the Japan and Korea studies do not alter the National Toxicology Program’s finding of “clear evidence” of cancer.

In a paper published earlier this year, Melnick and Moskowitz concluded that, based on the NTP cancer findings, current FCC and ICNIRP exposure limits would need to be at least 200 times lower to protect against cancer risk from 8 hours of daily exposure. The International Commission on the Biological Effects of Electromagnetic Fields is calling on governments to implement policies that reduce public exposure and inform cell phone users on how to minimize their risk.

Ronald L. Melnick, PhD, lead author and retired toxicologist at the National Institute of Environmental Health Sciences, who led the design of the original NTP radiofrequency radiation studies:

“The Japan and Korea studies cannot be used as proof of safety. To properly verify a study that found clear evidence of rare tumors like heart schwannomas, follow-up research must be designed with equal or greater sensitivity. By dropping the highest exposure level, testing only a single dose, and using fewer animals, these follow-up underpowered studies failed to meet basic FDA and OECD testing guidelines and were systematically biased toward finding no significant effect. These studies appear to be engineered to come back negative, no matter what the true biology is.

In short, the Japan and Korea studies cannot be used to invalidate the National Toxicology Program’s peer-reviewed findings of carcinogenicity or to justify the FCC’s and ICNIRP’s thermal-based exposure limits.”

Joel M. Moskowitz, PhD, School of Public Health, University of California, Berkeley, whose research focuses on the public health implications of wireless radiation exposure:

“Millions of people carry cell phones against their bodies for hours a day, and children are being exposed over far longer lifetimes than any generation before them. Public health decisions about safety limits should be built on the most rigorous animal evidence available, not on studies constructed in a way that was unlikely to detect harm even if it exists. We cannot allow flawed experimental designs to shield outdated safety guidelines from necessary, health-protective revisions. The scientific evidence on cancer and other biological effects is sufficient to warrant policies to reduce exposure.”

Dr. Paul Héroux, Department of Epidemiology, Biostatistics and Occupational Health, McGill University:

“These studies did not reproduce the original methodology, exposure assessment, or study conditions. From a biostatistical perspective, testing only 70 animals at a single dose level leaves a study severely underpowered to detect rare carcinogenic events. Without multiple dose groups and adequate sample sizes, finding ‘no statistically significant effect’ is an artifact of poor study design rather than evidence of safety. Importantly, when the NTP and Korean and Japanese studies are considered together, the overall evidence confirms cancer risk.” 

Implications for Public Policy and Public Health

The authors state that governments have a responsibility to protect public health by ensuring that exposure limits are based on the strongest available scientific evidence, not on studies that lack the scientific rigor necessary to detect known hazards. They conclude that the Japanese and Korean follow-up studies cannot be relied upon to dismiss the U.S. National Toxicology Program’s findings or to delay protective action. Before negative validation studies can be interpreted as evidence against the NTP’s findings, they must match or exceed the original study’s design, including the same animal model, exposure regimen, adequate group sizes, multiple exposure levels, and sufficient statistical power. Accordingly, they state that the WHO’s International Agency for Research on Cancer (IARC) and regulatory agencies should base hazard evaluations and public health policies on the strongest available evidence.

ICBE-EMF maintains that current U.S. and ICNIRP exposure limits for cell phones, Wi-Fi, smart meters, and cell towers are not adequately protective because a substantial body of research reports cancer and other biological effects, including DNA damage, oxidative stress, neurological effects, and reproductive harm. The Commission calls on governments to halt the rollout of new wireless technologies until independent safety assessments are completed and to adopt policies that reduce RF radiation exposure risks.

Scientific reference:

Melnick, R.L., Moskowitz, J.M., Héroux, P. et al. Conflicting views in experimental carcinogenesis: a commentary on design and methodological deficiencies in the follow-up validation studies on radiofrequency radiation. Environ Health 25, 66 (2026). https://doi.org/10.1186/s12940-026-01324-5

About the ICBE-EMF 

ICBE-EMF is an international consortium of scientists, doctors, and researchers with expertise and peer-reviewed publications on the biological and health effects of electromagnetic fields, including RF radiation. The Commission is committed to upholding the highest standards of scientific research and makes science-based recommendations to ensure the protection of the public and the environment. 

https://icbe-emf.org/flawed-validation-studies-do-not-negate-the-established-evidence-that-cell-phone-radiation-causes-cancer-in-rats-scientists-conclude/


Conflicting views in experimental carcinogenesis: a commentary on design and methodological deficiencies in the follow-up validation studies on radiofrequency radiation

Melnick RL, Moskowitz JM, Héroux P, on behalf of International Commission on the Biological Effects of Electromagnetic Fields. Conflicting views in experimental carcinogenesis: a commentary on design and methodological deficiencies in the follow-up validation studies on radiofrequency radiation. Environ Health 25, 66 (2026). https://doi.org/10.1186/s12940-026-01324-5.

Abstract

Conflicting views in experimental carcinogenesis often arise due to differences in study design among reported studies. For carcinogenicity assessments, regulatory agencies, such as the US Food and Drug Administration (FDA), and intergovernmental advisory organizations, such as the Organization for Economic Co-operation and Development (OECD), specify the use of at least three dose levels plus control group for trend analyses, with the highest dose inducing a measurable toxic response. In addition, there needs to be a sufficient number of animals per group to have adequate power to detect a true carcinogenic effect. Departure from such recommendations can weaken the interpretations of study results. We examine here two recent carcinogenicity studies from Japan and Korea that were conducted following the positive carcinogenicity study of radiofrequency radiation (RFR) in experimental animals by the National Toxicology Program (NTP). The Japan and Korea follow-up studies used fewer animals per group, a single RFR exposure group, and a lower exposure level than the NTP study. Not surprisingly, while the NTP study revealed the carcinogenicity of RFR, the Japanese and Korean studies, which had reduced statistical power compared to the NTP study, issued conclusions conflicting with those of the more substantial NTP study on the health effects of RFR. In general, carcinogenicity studies with weaker doses, fewer exposure groups, and reduced statistical power should not be used to test the validity of more robust studies.

Excerpt

Despite the numerous limitations in their study design, the authors of the Japan-Korea studies concluded there is “no reproducible carcinogenic potential of mobile phone-type RF exposure in rats,” and that alternatives to the ICNIRP “recommend[ed] exposure limits for RF radiation based on thermal effects” are inconclusive [3]. These statements reflect ideological support for ICNIRP’s thermal-only mechanism of adverse effects and its repeated dismissal of the validity of the NTP carcinogenicity studies (e.g [12]). The project’s principal investigator is a member of ICNIRP, and the advisory committee that provided oversight and guidance throughout this project was heavily represented by current and past members of ICNIRP, suggesting a strong influence of ICNIRP in the design and interpretation of these studies.

In conclusion, methodological shortcomings due to the design choices in the Japan–Korea studies, specifically the restriction to a single exposure group of 4 W/kg of CDMA-modulated RFR and reduced statistical power, systematically biased the study toward null results and eliminated the possibility of detecting a positive trend. Consequently, these findings cannot be used to reasonably refute the peer-reviewed evidence of toxicity and carcinogenicity of CDMA- and GSM-modulated RFR in the NTP studies, nor to reinforce ICNIRP’s thermal-based exposure limits. It is also important to note that the increases in schwannomas and gliomas reported in experimental studies of RF-EMF are of the same tumor types (glioma and vestibular schwannoma) that were increased in epidemiological studies in which brain cancer risk was increased among heavy users of mobile phones [13]. The example described in this commentary demonstrates how limited and divergent experimental designs and potential biases in the interpretation of experimental carcinogenicity results can lead to conflicting views on the health effects of RFR.

Open access: https://link.springer.com/article/10.1186/s12940-026-01324-5

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The International Collaborative Animal Study of Mobile Phone Radiofrequency Radiation Carcinogenicity and Genotoxicity

Imaida K, Kawabe M, Wang J, Yokohira M, Imai N, Han K-H, Kim Y-B, Jeon SB, Kim HY, Ahn YH.The International Collaborative Animal Study of Mobile Phone Radiofrequency Radiation Carcinogenicity and Genotoxicity: The Japanese Study. Toxicol Sci. 2026. 1/13/26. https://doi.org/10.1093/toxsci/kfag002.

Abstract

The potential carcinogenic and genotoxic effects of radiofrequency electromagnetic fields, particularly those emitted by mobile communication systems, have raised public health concerns. A previous study by the U.S. National Toxicology Program suggested increased incidences of gliomas and cardiac schwannomas in rats exposed to high levels of RF radiation. To evaluate these findings, an international collaborative study was initiated between Japan and Korea.

Male Hsd:Sprague Dawley® SD® rats were exposed to 900 MHz CDMA-modulated RF-EMFs at a whole-body specific absorption rate of 4 W/kg for 18 hours and 20 minutes daily over two years. The study included a 28-day preliminary toxicity study, genotoxicity assays (alkaline comet and micronucleus tests), and a two-year carcinogenicity assessment. All procedures followed OECD guidelines and Good Laboratory Practice. No statistically significant increases in the incidences of neoplastic or non-neoplastic lesions were found in any major organ, including the brain, heart, and adrenal glands. Genotoxicity assays revealed no evidence of DNA damage or chromosomal aberrations in RF-exposed rats. A higher survival rate in the RF-exposed group, likely due to lower body weight and food consumption, was observed.

This study performed in Japan, jointly planned and executed by Japan and Korea, provides strong evidence that long-term exposure to 900 MHz RF-EMFs did not produce reproducible carcinogenic or genotoxic effects in male rats. Combined with data from the Korean counterpart study, these results are expected to contribute to future international assessments of the carcinogenic potential of electromagnetic radiation.

Open access: https://academic.oup.com/toxsci/article/209/3/kfag002/8423504

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The International Collaborative Animal Study of The Carcinogenicity and Genotoxicity of Mobile Phone Radiofrequency Radiation: The Korean Study

Kim HS, Han KH, Kim YB, Jeon SB, Lee AK, Moon JI, Choi HD, Imaida K, Yokohira M, Kawabe M, Imai N, Wang J, Ahn YH. The International Collaborative Animal Study of The Carcinogenicity and Genotoxicity of Mobile Phone Radiofrequency Radiation: The Korean Study. Toxicol Sci. 2026 Jan 16:kfag001. doi: 10.1093/toxsci/kfag001. 

Abstract

A chronic bioassay investigating radiofrequency (RF) carcinogenicity, intentionally designed to be conducted simultaneously in Korea and Japan, using the same research protocol and experimental environment. The study aimed to assess the potential carcinogenicity of Code Division Multiple Access (CDMA)-modulated 900 MHz RF signals at a whole-body specific absorption rate (SAR) of 4 W/kg, which is the reference level of the international human safety guideline, and to verify the key findings from the National Toxicology Program (NTP) study at that SAR level. Two reverberation chamber systems were used for RF exposures, and the same study protocols were followed. Male Harlan Sprague-Dawley (Hsd: Sprague Dawley® SD®) rats were randomly assigned to cage-control, sham-exposed, or RF-exposed groups. The exposure started on gestational day 5 and lasted for 18 hours and 20 minutes each day, with 10-minute on/off cycles. The project included a 28-day toxicity study, a 2-year carcinogenicity study, and a 14-week genotoxicity test. Histopathological evaluations were conducted in a partially blinded manner. The results were independently analyzed and submitted separately based on each country's research findings. In the Korean study, no statistically significant changes in tumor incidence or survival rates were observed. No significant RF-related effects were detected in the heart, brain, or adrenal glands. No changes in body temperature. Genotoxicity tests showed no evidence of DNA damage or mutation. In conclusion, the Korean part found that long-term exposure to CDMA-modulated 900 MHz RF was neither carcinogenic nor genotoxic at a SAR of 4 W/kg in male rats.

Open access: https://academic.oup.com/toxsci/article/209/3/kfag001/8428133

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An International Collaborative Animal Study of the Carcinogenicity of Mobile Phone Radiofrequency Radiation: Considerations for Preparation of a Global Project

Ahn YH, Imaida K, Kim YB, Han KH, Pack JK, Kim N, Jeon SB, Lee AK, Choi HD, Wang J, Kawabe M, Kim HS. An International Collaborative Animal Study of the Carcinogenicity of Mobile Phone Radiofrequency Radiation: Considerations for Preparation of a Global Project. Bioelectromagnetics. 2022 May;43(4):218-224. doi: 10.1002/bem.22407. 

Abstract

Radiofrequency radiation (RFR) was classified as a "possible" human carcinogen in 2011, which caused great public concern. A carcinogenicity study by the National Toxicology Program (NTP) found Code Division Multiple Access-and Global System for Mobile Communications-modulated mobile phone RFR to be carcinogenic to the brain and heart of male rats. As part of an investigation of mobile phone carcinogenesis, and to verify the NTP study results, a 5-year collaborative animal project was started in Korea and Japan in 2019. An international animal study of this type has two prerequisites: use of the same study protocol and the same RF-exposure system. This article discusses our experience in the design of this global study on radiofrequency electromagnetic fields (RF-EMFs).

Open access: https://onlinelibrary.wiley.com/doi/10.1002/bem.22407

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Monday, November 21, 2016

Four lectures on wireless radiation health effects

The slides from three lectures about the health effects of wireless radiation presented by Dr. Dariusz Leszczynski in Melbourne, Australia are available from his blog site, "Between a Rock and a Hard Place."
  • "How probable are health effects of radiation from wireless transmitting devices?"
  • "Explaining ambiguous science requires high ethics and low conflict of interest"
  • "Health effects of wireless radiation--possible or probable"
Dr. Leszczynski has 20 years of experience researching the effects of electromagnetic fields on health. He is an adjunct professor of biochemistry at the University of Helsinki, Finland and Editor-in-Chief of the journal, "Frontiers in Radiation and Health." 

He was one of 31 members of the expert working group convened by the International Agency for Research on Cancer of the World Health Organization in 2011 that classified radio frequency radiation as "possibly carcinogenic to humans" (Group 2B)." In his recent lectures he argues that we have sufficient research evidence to change this classification to "probably carcinogenic to humans" (Group 2A).



The slides from my recent lecture to MPH students enrolled in the School of Public Health at the University of California, Berkeley are now available.
  • "Wireless Phone Radiation Risks and Public Health"