Smoking and risk of total and fatal prostate cancer in United States health professionals

Abstract

Studies that have examined the relationship between cigarette use and prostate cancer incidence have yielded inconsistent results, although most studies have suggested that smoking is related to the occurrence of fatal prostate cancer. We evaluated prospectively the relationship between cigarette smoking and total, distant metastatic, and fatal prostate cancer in 47,781 male health professionals throughout the United States followed with questionnaires. From 1986 to 1994, we documented 1369 men with prostate cancer (excluding stage A1). One hundred fifty-two of the men had distant metastatic disease at diagnosis, and 103 fatal cases occurred from 1986 to 1994. Early (before age 30), late (within recent 10 years), and lifetime cumulative smoking history were unrelated to risk of total prostate cancer. However, men who had smoked 15 or more pack-years of cigarettes within the preceding 10 years were at higher risk of distant metastatic prostate cancer [multivariate relative risk (RR), 1.81; 95% confidence interval (CI), 1.05-3.11; P (trend), 0.03] and fatal prostate cancer [RR, 2.06; CI, 1.08-3.90; P (trend), 0.02] relative to nonsmokers. Within 10 years after quitting, the excess risk among smokers is eliminated. The higher rate of fatal prostate cancer among smokers did not appear to result from confounding by diet or other lifestyle factors, different screening behavior between smokers and nonsmokers, or from other smoking-related comorbidities. Our results indicate that although smoking was unrelated to prostate cancer incidence, recent tobacco use had a substantial impact on the occurrence of fatal prostate cancer.