RF-026Original text reviewed
Long-term, low-level microwave irradiation of rats
The reported finding
Primary malignant lesions in 18/100 exposed vs 5/100 sham. Age-stratified Mantel-Haenszel OR 4.27, p=.006; death-time surrogate analysis p=.006. No significant specific tumour-site increase or all-neoplasms increase; longevity comparable.
Reading it carefully
Pooling across histologically different organs/tumours and numerous endpoints limits inference; one intensity/one sex; authors considered biological meaning uncertain. SAR declines with growth. Not a demonstrated schwannoma replication.
Inside the study
Exposure conditions
2450 MHz pulsed microwaves: 800 pulses/s, 10 µs width, 8 Hz square-wave modulation; whole-body SAR approximately 0.4 to 0.15 W/kg as animals grew; 21.5 h/day, 7 days/week, 25 months from 8 weeks of age. Individual circularly polarised waveguides.
Design & controls
100 male Sprague-Dawley rats exposed, 100 sham; 10/group interim sacrifice at 13 months; 200 animals examined pathologically.
Related research & shared cohorts
University of Washington/USAF programme. Guy et al. 1985, USAFSAM-TR-85-64, Volume 9/AD-A159512, and component reports describe the same animals; count once.
The protection question raised
How much weight can the pooled malignant-lesion increase carry when single-site and overall-neoplasm results were not significant? It remains relevant chronic-pathology history, with uncertainty about biological meaning.
Source verification
Original 28-page published article reviewed, including Tables 2-4, survival and discussion; 1985 USAF summary checked as same programme.
Where to find the result
pp 469-470 abstract; p 478 exposure; pp 487-488 survival/pathology; p 490 Table 2; p 491 statistics; p 492 Table 4; pp 493-494 interpretation/funding.
Editorial notices
Scite metadata/publisher and targeted DOI-notice search 2026-10-20: no correction/retraction/concern located.
Funding
USAF School of Aerospace Medicine contracts F33615-78-C0631 and F33615-80-C-0612; partial NCI grant CA33752. No modern conflict declaration located.
Conflicts of interest
Not established from retrieved material.
Original publication
Chou CK, Guy AW, Kunz LL, Johnson RB, Crowley JJ, Krupp JH. Long-term, low-level microwave irradiation of rats. Bioelectromagnetics. 1992;13(6):469-496. doi:10.1002/bem.2250130605.