Weight change in breast cancer survivors compared to cancer-free women: A prospective study in women at familial risk of breast cancer

Background: This study prospectively examines weight gain in breast cancer survivors compared with cancer-free women from a familial risk cohort. Methods: Absolute and percent weight change over 4 years was compared among 303 breast cancer survivors and 307 cancer-free women matched on age and menopausal status, from the same familial risk cohort. Linear and logistic regression was used to estimate the association between survivor status and weight gain. Results: Overall, breast cancer survivors gained significantly more weight [β = 3.06 pounds; 95% confidence intervals (CI), 0.94-5.17] than cancer-free women. Significant weight gain was observed in survivors diagnosed less than 5 years prior to baseline (β = 3.81 pounds; 95% CI, 1.22-6.29) and women with estrogen receptor (ER)-negative tumors (β = 7.26 pounds; 95% CI, 2.23- 12.30). Furthermore, survivors treated with chemotherapy were 2.1 times more likely to gain at least 11 pounds during follow-up compared with cancer-freewomen(OR, 2.10;95%CI, 1.21-3.63). Weight gain was even greater among survivors who took statins while undergoing chemotherapy treatment (P_interaction = 0.01). Conclusion: This is the first study to demonstrate that weight gain is an important issue in breast cancer survivors with a familial risk. In the first five years posttreatment, breast cancer survivors gain weight at a faster rate than cancer-free women, particularly after chemotherapy and statin use but not after hormone therapy alone. Impact: Our findings provide support for the development of weight gain interventions for young breast cancer survivors with a familial risk.