Weight gain among women with breast cancer after initiating endocrine therapy is a common occurrence and is associated with greater likelihood of worse outcomes as well as have an increased risk of dying from any cause. However, the risk factors for weight gain during adjuvant endocrine therapy have not been identified.
Researchers evaluated 321 women with a breast cancer diagnosis at stage 0-III starting endocrine therapy to determine if there is an association between weight gain during endocrine therapy, menopausal status, demographic factors, and emerging symptoms. The primary end point was weight gain. Any symptom (pain interference, depression, anxiety, fatigue, sleep disturbance, and physical function) that worsened at 3 and/or 6 months compared with baseline measures were considered emergent. Symptoms were assessed at baseline, 3, 6, 12, 24, 36, 48, and 60 months.
The 309 participants with baseline and ≥1 follow-up measurements for weight were included in the analysis. Median follow-up length was 56 months. Most of the women were diagnosed with stage I-II (85%), premenopausal (31%), and white (84%). Before starting endocrine therapy, some women had already completed other surgeries or treatments, including mastectomy (45%), radiation (66%), and chemotherapy (28%). The majority (82%) of postmenopausal patients had begun aromatase inhibitor therapy, while a greater proportion (96%) of premenopausal patients were on tamoxifen.
More black (66%) than white (61%) participants were overweight/obese at baseline. Considering menopausal status, 51% of premenopausal and 34% of postmenopausal participants gained ≥5% of body weight over baseline (P <.001). For each symptom assessed, >20% of participants exhibited emergent symptoms. Scores for pain interference and worse physical function scores at 3 months and/or 6 months were associated with weight gain depending on menopausal status (P ≤.05). Factors associated with weight gain among premenopausal participants were type of endocrine therapy (aromatase inhibitor vs tamoxifen; P = .08), prior mastectomy (P = .09), emergent pain interference (P = .05), and race (white vs other; P = .02).
Premenopausal women with breast cancer are more likely to gain weight after initiation of and during endocrine therapy. Consequently, these women are at greater risk of worse outcomes compared with postmenopausal women. Therefore, it is important to identify which premenopausal women are more likely to gain weight. Results from the current study indicate increasing pain within a few months after beginning endocrine therapy, treatment with aromatase inhibitor, mastectomy, and race are risk factors that may distinguish those premenopausal women at risk for weight gain, allowing for the development of appropriate treatment plans.
Source: Uhelski A-CR, Lim D, Blackford AL, et al. Factors associated with weight gain during endocrine therapy for breast cancer. American Society of Clinical Oncology Virtual Meeting; June 4-8, 2021. Abstract 12076.