Brain Tumors More Likely in Male than Female Rats
Historical Controls Show the Difference
One common criticism of the new NTP cell phone cancer study is that, unlike the male rats, there was no significant increase in tumors among female rats.
For instance in its latest assault on the NTP results, the New York Times is running a comment by a pediatrics professor in Indiana, in which he states:
“It’s also odd that increased cancer was seen only in male rats and not in female rats. Do we believe that females are protected from cell phone radiation?”
The answer is in the NTP report. The tables on pp.9-11 show a clear difference between male and female rats with respect to the incidence of spontaneous tumors among the NTP historical controls. Male rats were more than ten times more likely to develop malignant gliomas (brain tumors) than females: 11 of 550 males developed glioma, compared to only 1 of 540 females.
For malignant schwannoma of the heart, the difference is less pronounced, but still evident. Males were more than twice as likely to develop this type of cancer than the females: 9/699 vs 4/699.
Note also that, while none of the control rats in the NTP cell phone study had glial or Schwann cell tumors (or pre-cancerous lesions, hyperplasias, in these two cell types), some exposed females did develop them but the increases did not reach statistical significance.
This is what Ron Melnick, who ran the NTP study before he retired in 2009, had to say about the male vs females tumor counts:
“It is not surprising that the exposed males had more tumors than the females given what we have seen in the historical controls. But we can go one step further, the fact that we saw any of these tumors in the exposed females but none in the concurrent controls adds support to the conclusion that cell phone radiation leads to cancer among rats.”
And: “Gender Differences in Chemical Carcinognesis in National Toxicology Program 2-Year Bioassays,” published in Toxicologic Pathology in 2012. The paper is open access.