Exercise effects on lean body mass, muscle strength and functional performance in patients with metastatic breast cancer: the randomized controlled PREFERABLE-EFFECT study

Abstract

Background: Low skeletal muscle mass and strength are common in patients with metastatic breast cancer (mBC) and have been associated with treatment toxicities and poor prognosis. The PREFERABLE-EFFECT study (NCT04120298) investigated exercise effects on body composition, muscle strength, and functional performance (secondary outcomes) in patients with mBC. Methods: Patients with mBC (n = 357) were randomized to a 9-month supervised aerobic, resistance and balance exercise program (EX) or control. Body composition (subset n = 66), lower body strength (subset n = 126), handgrip strength and functional performance were assessed at baseline, 3 and 6 months. Changes between groups were compared using linear mixed models for repeated measures. Results: EX significantly increased whole body lean mass at 3 months (between-group difference = 0.79 kg, 95%CI [0.14; 1.44], effect size = 0.14), appendicular skeletal muscle mass at 3 months (0.60 kg, [0.22; 0.97], ES = 0.19) and 6 months (0.48kg, [0.09; 0.87], ES = 0.15), and lower body strength at 3 months (18.32 kg, [7.58; 29.06], ES = 0.44) and 6 months (34.22 kg, [23.0; 45.45], ES = 0.83) compared to control. EX also improved functional performance, including balance, compared to control. Conclusions: The results support the promotion of supervised exercise for patients with mBC, with beneficial effects on skeletal muscle mass, muscle strength and physical performance. Trial registration: The PREFERABLE-EFFECT study was registered on ClinicalTrials.gov on October 9, 2019 (NCT04120298).