Men's health supplement use and outcomes in men receiving definitive intensity-modulated radiation therapy for localized prostate cancer

Background: Approximately 50% of newly diagnosed cancer patients start taking dietary supplements. Men's health supplements (MHSs), which we define as supplements that are specifically marketed with the terms men's health and prostate health (or similar permutations), are often mislabeled as having potential anticancer benefits. Objective: We evaluated the effects of MHSs on patient outcomes and toxicities in patients who were undergoing definitive intensity modulated radiation therapy (IMRT) for localized prostate cancer. Design: This retrospective analysis included patients who were being treated at a National Cancer Institute designated comprehensive cancer center and consented to have information stored in a prospective database. MHSs were queried online. Outcome measures were freedom from biochemical failure (FFBF) (biochemical failure was defined with the use of the prostate-specific antigen nadir + 2-ng/mL definition), freedom from distant metastasis (FFDM), cancer-specific survival (CSS), and overall survival (OS) as well as toxicities. Kaplan-Meier analysis, log-rank tests, Fine and Gray competing-risk regression (to adjust for patient and lifestyle factors), and Cox models were used. Results: From 2001 to 2012, 2207 patients were treated with IMRT with a median dose of 78 Gy, and a median follow-up of 46 mo. Of these patients, 43% were low risk, 37% were intermediate risk, and 20% were high risk; 10% used MHSs. MHSs contained a median of 3 identifiable ingredients (range: 0-78 ingredients). Patients who were taking an MHS compared with those who were not had improved 5-y OS (97% compared with 92%, respectively; P = 0.01), but there were no differences in the FFBF (94% compared with 89%, respectively; P = 0.12), FFDM (96% compared with 97%, respectively; P = 0.32), or CSS (100% compared with 99%, respectively; P = 0.22). The unadjusted association between MHS use and improved OS was attenuated after adjustment for patient lifestyle factors and comorbidities. There was no difference in toxicities between the 2 groups (late-grade 3-4 genitourinary <3%; gastrointestinal <4%). Conclusion: The use of MHSs is not associated with outcomes or toxicities.