Weight gain in hormone receptor-positive (HR+) early-stage breast cancer: is it menopausal status or something else?

This study investigates weight trajectories in pre- versus postmenopausal breast cancer (BC) survivors diagnosed with hormone receptor-positive tumors, with a specific focus on discerning menopausal status and type of endocrine treatment (ET) as risk factors for weight gain during ET. We conducted a retrospective review of electronic medical records. Descriptive statistics and Chi-squared and t tests were used to compare pre- and postmenopausal women. Chi-squared tests and ANOVA were used for within-group associations between patient characteristics and weight trajectories. Log-binomial regression models were used to estimate relative risk for weight gain. The final sample was 32% premenopausal (n = 140) and 68% postmenopausal (n = 298). Relative risk (RR) for weight gain during ET was highest in women who were premenopausal (RR = 1.29, 1.03–1.52) and had Stage 3 BC (RR = 2.12, 1.59–2.82), mastectomy (RR = 1.49, 1.19–1.88), axillary node dissection (RR = 1.39, 1.11–1.73), and chemotherapy (RR = 1.80, 1.37–2.36). For each kg of weight gained between BC diagnosis and start of ET, and for each additional year of age, RR of gaining weight during ET decreased (RR = 0.98, 0.97–0.99, and RR = 0.99, 0.98–0.99, respectively). Menopausal status and type of ET were not significant predictors of weight gain. In multivariable analysis, only weight loss between BC diagnosis and start of ET was significant. The association of weight loss prior to ET and subsequent substantial weight gain during ET warrants further investigation.