The impact of weight loss on physical function and symptoms in overweight or obese breast cancer survivors: results from POWER-remote

Purpose: In pre-planned observational analysis of the POWER-remote trial, we examined the impact of weight loss on patient-reported outcomes (PROs). We hypothesized a priori that survivors with ≥ 5% weight loss would have improved physical function (PF) at 6 months vs. those who did not. Methods: Patients with stage 0-III breast cancer who completed local therapy and chemotherapy with BMI ≥ 25 kg/m² were randomized to POWER-remote (telephone coaching; diet/activity tracking) or self-directed weight loss (booklet). Participants completed PROs at baseline, 6, and 12 months: PROMIS PF, pain, fatigue, anxiety, depression, sleep; FACT-endocrine symptoms; MOS-sexual function. Changes in PROs among those with ≥ 5% weight loss vs. those with < 5% were tested with multivariable mixed effect models, across randomized groups. Results: Of 94 women who completed PROs, 84 and 69 participants were evaluable at 6 and 12 months, respectively. Regardless of intervention, PF improved in those with ≥ 5% weight loss vs. those with < 5% at 6 months (4.4 vs. 0.3 points; p = 0.02) and 12 months (3.6 vs. 0 points; p = 0.04). While endocrine symptoms, fatigue, and anxiety improved at 6 months in those who lost ≥ 5%, differences were not significant vs. those who lost < 5%. There was no significant change within or between groups in sexual function, depression, or sleep. Findings at 12 months were similar, except pain improved in those losing ≥ 5%. Conclusions: These results support the benefits of weight loss in overweight/obese breast cancer survivors. Implications for Cancer survivors: Weight management in breast cancer survivors may improve PF.