Researchers at UCLA's Jonsson Comprehensive Cancer Center have shown for the first time that men with prostate cancer who closely adhere to World Cancer Research Fund lifestyle recommendations have a significantly reduced risk of highly aggressive prostate tumors.
The nine WCRF recommendations suggest desirable ranges for body mass index and physical activity and provide guidelines for the consumption of foods of low caloric density, fruits and non-starchy vegetables, salt, legumes and unrefined grains, and red meat.
While the recommendations are intended to decrease individuals' overall risk of cancer and are also recommended for cancer survivors, the current study shows that adherence may also benefit men who have recently been diagnosed with prostate cancer, said Lenore Arab, a member of the Jonsson Cancer Comprehensive Center and a professor in the UCLA departments of medicine and biological chemistry.
The study is currently available online in the journal Nutrition and Cancer and will be published in an upcoming print edition.
Led by Arab, the research team studied 2,212 newly diagnosed prostate cancer patients who were enrolled in the North Carolina–Louisiana Prostate Cancer Project. The men were all either African-American or white and were between the ages of 40 and 70.
The researchers found that adherence to fewer than four of the nine WCRF recommendations predicted a 38 percent increased risk of aggressive tumors, compared with adherence to four or more. That statistically significant finding was similar among black and white men, despite a higher risk of highly aggressive tumors among black men at baseline.
The team also found that, in particular, eating less than 500 grams of red meat per week or less than 125 total kilocalories per 100 grams of food each day provided statistically significantly protection against highly aggressive tumors for all the study subjects.
Patients were ranked on their adherence, receiving one point for each of the recommendations they followed. Each point in a patient's total adherence score corresponded to a 13 percent reduction in the risk of aggressive cancer. A total adherence score of less than four points predicted an increased risk of aggressive tumors in all patients.
"Most men are at risk of prostate cancer, but it is the level of aggressiveness of disease that is most clinically relevant," Arab said. "These findings suggest that even men with prostate cancer can take control of their disease and moderate its aggressiveness through diet and lifestyle choices."
The aggressiveness of the men's prostate cancer was measured using Gleason grading system scores, blood levels of prostate-specific antigen (PSA), and TNM malignant tumor classification. Adherence to the recommendations was based on point scores and odds ratio estimates.
The findings, Arab said, assume that patients' reports reflect their long-term dietary habits, an assumption supported by research indicating that diet is relatively stable in adulthood.
This research was supported by the U.S. Department of Defense through the Prostate Cancer Project.
