The World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR) published eight recommendations for cancer prevention but they are not targeted at prostate cancer prevention. Little is known whether adherence to these recommendations or to disease specific dietary guidelines reduces prostate cancer risk.
We investigated whether adherence to the WCRF/AICR recommendations for cancer prevention and a prostate cancer specific dietary index are associated with prostate cancer risk in the Prostate Testing for Cancer and Treatment (ProtecT) trial.
We conducted a nested case-control study of 1,806 screen-detected prostate cancer cases and 12,005 controls. We developed a prostate cancer dietary index by incorporating three dietary factors most strongly associated with prostate cancer. Scores were computed to quantify adherence to the WCRF/AICR recommendations and the prostate cancer dietary index separately. Associations between the scores and prostate cancer risk were estimated by conditional and multinomial logistic regression models. Analyses were additionally conducted investigating grade and stage of prostate cancer.
The prostate cancer dietary index score was associated with decreased risk of prostate cancer (OR per 1 score increment: 0.91, 95% CI: 0.84, 0.99; p-trend=0.04) but the WCRF/AICR index score was not (OR: 0.99, 95% CI: 0.94, 1.05; p-trend=0.82). There was no heterogeneity in association by prostate cancer stage (p=0.46) or grade (p=0.86). Greater adherence to recommendations to increase plant foods (OR per 0.25 index score increment: 0.94; 95% CI: 0.89, 0.99; p-trend=0.02) and tomato products (OR adherence vs. non-adherence: 0.82; 95% CI: 0.70, 0.97; p=0.02) were inversely associated with overall prostate cancer risk.
Adherence to the prostate cancer-specific dietary recommendations was associated with decreased risk of prostate cancer. High intake of plant foods and tomato products in particular may help protect against prostate cancer.