269MO The effects of exercise on sexual health and breast cancer-specific symptom burden in women with metastatic breast cancer: Results of the multinational randomized PREFERABLE-EFFECT trial

Women with metastatic breast cancer (mBC) experience breast cancer- and treatment-related side effects that impair activities of daily living. Evidence for exercise effects on rarely addressed problems such as sexual health or body image is lacking to date, especially for patients with advanced disease. Thus, we investigated the effects of a structured exercise intervention in women with mBC on sexual health and breast cancer-specific symptoms. The multinational EFFECT study, including 355 women (and 2 men) with mBC from 5 European countries and Australia, randomly assigned participants to either usual care (UC) or a 9-month supervised exercise program (EX) combining aerobic, resistance, and balance exercises. All participants received general exercise advice and an activity tracker. Breast cancer-specific symptoms (EORTC QLQ-BR45) were assessed at baseline, 3, 6 (primary timepoint), and 9 months. Intervention effects were analyzed on an intent-to-treat basis with mixed models for repeated measures, adjusted for baseline values of the outcome variable and stratification factors (line of treatment and study center). Female participants had a mean ± SD age of 55.4 ± 11.1 years, mostly received 1st/second-line treatment at study enrollment (74.8%) and had bone metastases (67.5%). At baseline, sexual functioning (17.1±21.2) was low, associated with older age and depressive symptoms. Almost half of sexually active women reported little sexual enjoyment, 26% of all participants reported moderate-to-severe endocrine sexual symptoms and 24% a poor body image. Exercise improved sexual functioning (effect size (ES)=0.28, p=.0031) and endocrine sexual symptoms (ES=0.25, p=.0026) at 6-month. The exercise effect on sexual functioning was sustained at 9-month (ES=0.23, p=.020). Women with mBC are likely to experience sexual problems and may have an impaired body image. Exercise can help improve sexual health in these patients. Further research should determine the optimal role of exercise in addressing symptom burden, possibly in conjunction with additional support.