WASHINGTON – Men who received androgen blockade therapy as part of prostate cancer treatment were less likely to develop a secondary lung cancer than were those who didn’t receive the hormone regimen.
The significant finding suggests that estrogen may fuel non–small cell lung cancers in both men and women, Dr. Hyunseok Kang reported at the annual meeting of the American Association for Cancer Research.
Dr. Hyunseok Kang
"Recent literature suggests estrogen receptors and aromatase play a role in the development of non–small cell lung cancers in women with breast cancer," Dr. Kang said. "Aromatase can convert testosterone to estrogen – which could increase the same risk in men."
This recently observed association prompted Dr. Kang, a fellow at Emory University, Atlanta, and his colleagues to investigate whether a similar hormone-mediated link might exist for men with prostate cancer – and whether blocking it could also block lung cancer.
The retrospective observational study pulled data from the Veterans Affairs Central Cancer Registry. It comprised 62,589 men who were diagnosed with prostate cancer between 1999 and 2008, with follow-up through 2010.
There were some significant – and important – baseline differences between the 20,378 men who underwent androgen blockade and those who did not. Men who received the treatment were significantly older (mean age, 71 years vs. 66 years) and slightly more likely to have ever smoked tobacco (73% vs. 71%).
Prostate cancer stage at diagnosis was also significantly different, with fewer of the hormone therapy group presenting at stage II (77% vs. 92%) and more presenting at stage IV (17% vs. 2%).
Men from the VA database were significantly more likely than the general population to develop lung cancer, whether they underwent androgen blockade therapy or not (1.8/100,000 men who received treatment and 2.4/100,000 men who did not receive treatment vs. 0.80/100,000 in the general population).
Of men in the VA database who received androgen treatment, 258 developed secondary lung cancers, compared with 508 men who did not receive treatment.
In an unadjusted model, men who had treatment were 18% less likely to develop a secondary lung cancer (hazard ratio, 0.82). That finding held in a multivariate analysis that adjusted for smoking and age (HR, 0.83).
The study was sponsored by the Veterans Health Administration. Dr. Kang had no financial disclosures.