A Prospective Study of Weight Gain in Women Diagnosed with Early-Stage Invasive Breast Cancer, Ductal Carcinoma In Situ, and Women Without Breast Cancer.

Background: Weight gain after breast cancer has been associated with recurrence and mortality. We therefore examined factors associated with ≥5% weight gain over 2-year follow-up of a cohort of newly diagnosed early-stage invasive breast cancer (EIBC) and ductal carcinoma in situ (DCIS) patients and age-matched controls without a breast cancer history. Materials and Methods: We interviewed participants 4-6 weeks after definitive surgical treatment (patients) or a negative/benign screening mammogram (controls). Multivariable logistic regression models were used to identify socioeconomic, psychosocial, and treatment factors associated with ≥5% weight gain over 2-year follow-up. Results: Overall, 88 (24%) of 362 EIBC patients, 31 (17%) of 178 DCIS patients, and 82 (15%) of 541 controls had ≥5% weight gain during follow-up. EIBC patients were more likely to experience ≥5% weight gain than DCIS patients (Odds ratio [OR] = 2.16; 95% confidence interval [95% CI] = 1.19-3.95) and controls (OR = 1.76; 95% CI = 1.23-2.51). Among EIBC patients, older patients (OR = 0.96; 95% CI = 0.93-0.99), patients who underwent endocrine therapy (OR = 0.43; 95% CI = 0.19-0.95), smokers (OR = 0.35; 95% CI = 0.14-0.86), and African Americans (OR = 0.23; 95% CI = 0.09-0.58) were less likely to have ≥5% weight gain than their respective counterparts. Among DCIS patients, older patients (OR = 0.94; 95% CI = 0.89-0.99) were less likely to have ≥5% weight gain. Among controls, smokers were more likely to have ≥5% weight gain (OR = 3.03; 95% CI = 1.49-6.17). Conclusions: EIBC patients were more likely than DCIS patients and controls to experience ≥5% weight gain over follow-up. Studies are necessary to elucidate mechanisms of weight gain in early-stage breast cancer survivors.