Effects of Exercise or Diet or Combined Interventions on Treatment Efficacy of Chemotherapy for Cancer: A Systematic Review.

[PURPOSE OF REVIEW] While exercise and dietary interventions in patients with cancer undergoing chemotherapy have been demonstrated to be safe and feasible and improve patient-reported outcomes, the effects on treatment efficacy have not been widely examined and remain unclear. This review aimed to examine the effects of exercise, dietary, and combined interventions on tumour response and time-to-event outcomes in patients with cancer undergoing chemotherapy.

[RECENT FINDINGS] A systematic review of intervention studies was conducted based on PRISMA guidelines Databases searched were PubMed, Medline, CINAHL, Embase, and Web of Science. Methodological quality and risk of bias were assessed using the RoB2 and ROBINS-I tools. A total of 21 studies, involving 1,384 cancer patients, were included. Exercise interventions were studied in 13 studies, nine of which were controlled. Two studies reported improvements in tumour response, although none demonstrated a significant impact on survival outcomes. Dietary interventions were investigated in seven studies, all of which used either ketogenic diets or fasting-mimicking diets; three of these studies were controlled and recruited patients with breast cancer. Among all studies, three showed significant increases in tumour response and survival outcomes. Finally, only one study evaluated the combined effects of exercise and diet, reporting a significant increase in pathological complete response rates in the intervention group. Exercise and dietary interventions, particularly ketogenic and fasting-mimicking diets, may enhance tumour response and survival during chemotherapy in some cases. However, the current evidence is limited and inconsistent. Well-designed randomized controlled trials are needed to better establish the efficacy of these interventions as adjuncts to chemotherapy.