Commentary: Is prostate cancer an infectious disease?

Serologic evidence of human papillomavirus 16 and 18 infections and risk of prostate cancer. cancer risk and serologic evidence of human papillomavirus infection: a population-based case-control study. between human-papillomavirus infection and risk of prostate cancer. den Berg BJ. Human papillomavirus antibody and risk of prostate cancer. In this issue, Leticia Fernandez and her fellow epidemiologists from Cuba, Barcelona, and Lyon report interesting findings of their case–control study in Havana, Cuba. 1 The report adds relevant information supporting the causal relationship between chronic inflammation and cancer development. The list of infections and chronic inflammatory states aetiologically linked to cancer is increasing and includes major human burdens such as carcinomas of the cervix, stomach, colon, liver, and bladder as well as some lymphomas. Although the cancer risk attributable to infections has been quoted as ~15.6%, 2 that estimate does not take into account the risk enhancement effect of chronic inflammation in multifactorial causal associations in common cancers such as those of the breast and colon. It is also well accepted that chronic inflammation affects the prognosis of cancer by as yet unclear mechanisms. This knowledge has led to many ongoing intervention trials of inhibitors of inflammation such as the non-steroidal anti-inflammatory drugs and the cyclooxygenase (Cox-2) inhibitors in dozens of cancer sites, with convincing beneficial effects on prognosis. Prostatic cancer is the second most frequent malignant neoplasia worldwide, accounting for 542 990 new cases and 204 313 deaths in 2000. 3 The incidence has been increasing recently in many countries, but the extent of confounding by the recent introduction and generalization of the PSA test for screening is difficult to evaluate. The experience in Cuba, where PSA testing is not done, clearly shows that the increasing trend is real. Most epidemiological studies have shown that sexual activity and prostatic cancer are causally associated. Indicators of sexual activity vary in their association with prostatic cancer in different studies, but the trend for a risk increase is clear and consistent. 4–6 The association with venereal diseases is also significant and consistent. These two sets of aetiological factors are obviously interrelated: greater sexual activity increases the chances of infection. It seems clear, however, that androgen secretion, which increases the sexual drive, has an independent IJE vol.34 no.1