A behavioral intervention that increases vegetable consumption does not reduce the risk for progression of early-stage prostate cancer, according to a study published in the January issue of the Journal of the American Medical Association.
J. Kellogg Parsons, M.D., from the UC San Diego Moores Comprehensive Cancer Center in La Jolla, California, and colleagues randomly assigned 478 men aged 50 to 80 years with biopsy-proven prostate adenocarcinoma, stage cT2a or less, to either a counseling behavioral intervention by telephone promoting consumption of seven or more daily vegetable servings or a control group that received written information about diet and prostate cancer (237 and 241 men, respectively). The primary analysis included 443 men.
The researchers identified 245 progression events (124 and 121 in the intervention and control groups, respectively). Time to progression did not differ significantly between the groups (unadjusted hazard ratio, 0.96 [95 percent confidence interval, 0.75 to 1.24]; adjusted hazard ratio, 0.97 [95 percent confidence interval, 0.76 to 1.25]). For the intervention and control groups, the 24-month Kaplan-Meier progression-free percentages were 43.5 and 41.4 percent, respectively (difference, 2.1 percent; 95 percent confidence interval, −8.1 to 12.2 percent).
"We now have good evidence that a diet rich in fruits and vegetables and light on red meat is not likely to impact need for treatment," a coauthor said in a statement. "But this study does not provide justification for eating anything you want, either."
