Nutrition care guidelines for men with prostate cancer undergoing androgen deprivation therapy: do we have enough evidence?

Background To review the evidence available to support clinical practice guidelines for dietary interventions aimed at mitigating the side effects of androgen deprivation therapy (ADT) in men with prostate cancer, and to identify future research priorities. Methods An analytical model was designed to select and interpret evidence for the effect of dietary interventions on ADT side effects. Key terms identified articles that investigated dietary interventions to mitigate ADT side effects among men treated for prostate cancer. Medline, Embase, Proquest, CINAHL, Cochrane databases, and PubMed were searched from inception through June, 2018. Clinical trial registries were also searched for up-to-date study protocols. Articles were not restricted on design. Methodological quality was assessed using the mixed methods appraisal tool. Results Sixteen articles met inclusion criteria, each with distinct dietary interventions. Twelve studies used interventions that combined diet with physical activity and/or medication and/or counselling. Four articles examined the effect of diet alone on ADT side effects. Of those, three articles measured changes to participants' dietary intake and influence on ADT side effects. One article showed daily caffeinated beverages improved cancer-related fatigue. Two articles showed no impact of isoflavone supplementation on hot flushes, quality of life, body mass index, or blood lipids. Dietary intake and compliance was poorly reported across all studies limiting knowledge of acceptability and feasibility for dietary interventions. Information on the nutrition care practices and views of clinicians treating men for prostate cancer is limited. No articles measured the impact of diet on long-term ADT side effects. Methodological quality of included papers ranged from weak to strong. Conclusions Current evidence for dietary interventions to mitigate ADT side effects is limited. Further investigations are warranted to explore the impact of changes in dietary intake on ADT side effects before practice guidelines can be considered.