A behavioral intervention can successfully motivate men with early-stage prostate cancer to modify their diet by increasing vegetable consumption. Eating more vegetables, however, will not alter the natural history of prostate cancer or otherwise prevent progression of localized disease, according to the results of the prospective Men’s EAting and Living (MEAL) Study.
Published in JAMA (2020; 323:140-8), the study was conducted through the Cancer and Leukemia Group B. It randomized 478 men who were being managed with active surveillance for early-stage prostate cancer to receive either behavioral intervention counseling that encouraged consumption of ≥7 fruit or vegetable servings per day or written information about diet and prostate cancer. Men were followed for 24 months post-randomization.
Dietary data and measurement of plasma carotenoids indicated that the behavioral intervention was effective for increasing intake of vegetables, cruciferous vegetables, and carotenoids. However, there were no statistically significant differences between the intervention and control groups in the primary outcome that assessed time to progression (adjusted hazard ratio, 0.97 [95% confidence interval, 0.76 to 1.25]) or in the prespecified secondary outcome comparing the intervention and control groups for total number [percentage] of patients who pursued active treatment during follow-up without meeting protocol-defined progression criteria (6 [2.7%] vs. 4 [1.8%]; p=.75). The hazard ratio for time to treatment was also not statistically significant.
Lead author J. Kellogg Parsons, MD, MHS, told Urology Times, “The prostate cancer survivorship care guideline from the American Society of Clinical Oncology and the Prostate Cancer Foundation endorse increased consumption of vegetables to improve outcomes for prostate cancer survivors, but these recommendations are based on expert opinion and findings from preclinical and observational studies. We believe ours is the first randomized controlled trial investigating a dietary intervention for prostate cancer, and in contrast to prevailing scientific and public opinion, our study’s findings do not support increasing vegetable intake to decrease prostate cancer progression in men with early-stage disease who are being managed with active surveillance.”