Factors associated with weight gain in pre- and post-menopausal women receiving adjuvant endocrine therapy for breast cancer

Purpose Weight gain after breast cancer poses health risks. We aimed to identify factors associated with weight gain during adjuvant endocrine therapy (AET). Methods Women initiating AET enrolled in a prospective cohort. Participants completed FACT-ES plus PROMIS pain interference, depression, anxiety, fatigue, sleep disturbance and physical function measures at baseline, 3, 6, 12, 24, 36, 48 and 60 months. Treatment-emergent symptoms were defined as changes in scores in the direction indicative of worsening symptoms that exceeded the minimal important difference at 3 and/or 6 months compared to baseline. We used logistic regression to evaluate associations of clinicodemographic features and treatment-emergent symptoms with clinically significant weight gain over 60 months (defined as ≥ 5% compared to baseline) in pre- and post-menopausal participants. Results Of 309 participants, 99 (32%) were pre-menopausal. The 60 months cumulative incidence of clinically significant weight gain was greater in pre- than post-menopausal participants (67% vs 43%, p < 0.001). Among pre-menopausal participants, treatment-emergent pain interference (OR 2.49), aromatase inhibitor receipt (OR 2.8), mastectomy, (OR 2.06) and White race (OR 7.13) were associated with weight gain. Among post-menopausal participants, treatment-emergent endocrine symptoms (OR 2.86), higher stage (OR 2.25) and White race (OR 2.29) were associated with weight gain while treatment-emergent physical function decline (OR 0.30) was associated with lower likelihood of weight gain. Conclusions Weight gain during AET is common, especially for pre-menopausal women. Clinicodemographic features and early treatment-emergent symptoms may identify at risk individuals. Implications for cancer survivors Patients at risk for weight gain can be identified early during AET. Clinical trials.gov identifier NCT01937052, registered September 3, 2013.