Smoking
Cigarette smoking has been associated with the development of several cancers, so it is reasonable that it could be related to prostate cancer, too. Some studies have linked prostate cancer to carcinogens present in tobacco smoke, and other studies have suggested that the impact of smoking on hormone levels may influence the development of prostate cancer. But, overall, the data are not convincing that there is a real, independent increase in risk from smoking. Some studies show a relationship; others do not. Two very large studies, however, have provided similar data supporting a weak relationship. One was a 26-year follow-up of nearly 250,000 veterans, including 4,600 prostate cancer deaths. The second was from a relatively younger cohort of 350,000 men in the Multiple Risk Factor Intervention Trial (MRFIT), including 826 deaths over 16 years of follow-up. The two studies showed remarkably similar results, a small dose-related increase in risk of death from smoking.
Recent evidence suggests a stronger effect of heavy smoking on the progression to fatal prostate cancer, rather than on overall incidence. A recent report from the Health Professionals Follow-Up study supports this. Smoking was not related to an increase in the overall incidence of prostate cancer, but heavy smokers (one-and-one-half pack per day) for the previous 10 years had about twice the risk for metastatic and fatal prostate cancer compared to nonsmokers. For some reason, smoking may have contributed to a relatively minor cancer becoming more aggressive. This relationship needs further study, but it supports not smoking if prostate health is a concern.
