Cruciferous vegetables may reduce aggressive prostate cancer risk

High intake of cruciferous vegetables, including broccoli and cauliflower, may be associated with reduced risk of aggressive prostate cancer, particularly extraprostatic disease, suggests a study to be published in the Journal of the National Cancer Institute.

Victoria A. Kirsh, PhD, of Cancer Care Ontario in Toronto, working with Richard B. Hayes, MD, of the National Cancer Institute, evaluated the association between prostate cancer risk and intake of fruits and vegetables in 1,338 patients with prostate cancer among 29,361 men in the screening arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.

Participants completed both a general risk factor and a 137-item food-frequency questionnaire at baseline. Cox proportional hazards models were used to estimate relative risks and 95% confidence intervals.

The team found that vegetable and fruit consumption was not related to prostate cancer risk overall; however, risk of extraprostatic prostate cancer decreased with increasing vegetable intake (RR=0.41, 95% CI=0.22 to 0.74). This association was mainly explained by intake of cruciferous vegetables (RR=0.60, 95% CI=0.36 to 0.98), in particular, broccoli (RR=0.55, 95% CI=0.34 to 0.89, for >1 serving per week vs. <1 serving per month) and cauliflower (RR=0.48, 95% CI=0.25 to 0.89 for >1 serving per week vs. <1 serving per month).

The researchers also found some evidence that risk of aggressive prostate cancer decreased with increasing spinach consumption, but the findings were not consistently statistically significant when restricted to extraprostatic disease.