# RF-001 — Malignant heart tumours after long term exposure

Why this matters
Male rats developed malignant tumours in cells that support nerves in the heart. The US government's finding raises a concrete question about long-term cancer protection. Translating this animal hazard to human exposure needs careful assessment; the experiment does not measure anyone's personal cancer risk.

Id: RF-001

Author: National Toxicology Program

Full Authors: National Toxicology Program (NTP)

Year: 2018

Title: NTP Technical Report on the Toxicology and Carcinogenesis Studies in Hsd:Sprague Dawley SD Rats Exposed to Whole-Body Radio Frequency Radiation at a Frequency (900 MHz) and Modulations (GSM and CDMA) Used by Cell Phones

Journal: NTP Technical Report 595

Citation: National Toxicology Program. NTP Technical Report on the Toxicology and Carcinogenesis Studies in Hsd Sprague Dawley SD Rats Exposed to Whole-Body Radio Frequency Radiation at a Frequency of 900 MHz and Modulations GSM and CDMA Used by Cell Phones. Research Triangle Park NC: NIEHS; 2018. NTP TR 595. doi:10.22427/NTP-TR-595.

Doi: 10.22427/NTP-TR-595

Pmid: 33562898

Topic: Tumours

Verification Group: Original text reviewed

Record Role: Original text reviewed

Featured: True

Exposure: 900 MHz; whole-body SAR 1.5, 3 or 6 W/kg; 10 minutes on/10 minutes off; about 9 hours 10 minutes RF-on daily, prenatal to two years.

Design: 105 offspring per sex/group initially; 90 per sex/group in two-year pathology cohorts; shared sham controls.

Finding: NTP classified male-rat heart schwannoma findings as clear evidence of carcinogenic activity for both GSM and CDMA. Counts were 0/90 sham versus 2/90, 1/90, 5/90 GSM and 2/90, 3/90, 6/90 CDMA.

Boundary: Animal disease endpoints; these whole-body exposures are not ordinary handset use. Control and exposed survival differed; NTP used survival-adjusted analyses.

Related: RF-002 is a separate laboratory programme. RF-005 uses interim animals from the NTP programme.

Protection Question: How should a controlled animal finding of malignant heart tumours inform long-term human protection, given the differences in exposure, survival and species? It identifies a cancer hazard under these experimental conditions, not an everyday-use risk estimate.

Access: Official full report consulted for current status, funding, contractor roles, pathology and peer review. Original final conclusions use clear evidence for male cardiac malignant schwannomas under both modulations; female findings are equivocal. Appendix L documents external peer review; the final categories replace draft categories, without implying a suppressed or secretly changed result.

Locator: Report pp 66 and 103, Tables 20 and 47; pp xxiii-xxiv conclusions; p viii formatting statement; pp ix-xiii contributor roles; p xvi peer-review remit; p xviii acknowledgments; pp xxiii-xxiv/124 conclusions; Appendix L peer review.

Notice: Current official PDF p viii states it was reformatted to meet new NTP publishing requirements and its content has not changed. Official report remains TR 595, November 2018; PubMed indexing in 2021 is not a new experiment. No correction, retraction or expression of concern located in official/PubMed and targeted DOI/title notice checks on 2026-10-20. The report's publication-details page prints NTP-TOX-595 in one DOI field; use NTP-TR-595 confirmed by official landing-page citation and PubMed.

Funding: NIEHS/NIH Intramural Research Program ES103316, ES103318 and ES103319; performed for NTP/HHS under federal contracts listed in the original report acknowledgments, p xviii. IIT Research Institute conducted studies; IT'IS constructed/maintained exposure system; NIST independently validated that system. Affiliations and contractor roles are documented, not inferred financial conflicts.

Conflicts: Not established from retrieved material.

Source Url: https://doi.org/10.22427/NTP-TR-595

Retrieval Links: https://doi.org/10.22427/NTP-TR-595 | https://ntp.niehs.nih.gov/publications/reports/tr/tr595 | https://ntp.niehs.nih.gov/sites/default/files/ntp/htdocs/lt_rpts/tr595_508.pdf | https://pubmed.ncbi.nlm.nih.gov/33562898/

Verification Date: 2026-10-20