Purpose: Changes in cancer therapy, in addition to changes in obesity prevalence, suggest the need for a current assessment of weight gain patterns following breast cancer diagnosis. The aim of this study was to evaluate factors associated with weight gain among breast cancer survivors prior to enrolling into a behavioral weight loss intervention. Methods: Anthropometric measures and data on weight-related factors were collected at baseline on 665 breast cancer survivors. Postdiagnosis weight gain was determined between entry into the trial and previous diagnosis up to 5 years. Multivariate logistic regression analyses were used to evaluate the association between weight gain and influencing factors. Results: The mean weight gain was 4.5 % body weight (standard deviation = 10.6); 44 % of women experienced ≥5 % body weight gain. The risk of weight gain was inversely associated with age (adjusted odds ratio (ORadj) = 0.97, 95 % confidence interval (95 % CI) 0.95-0.99), Hispanic ethnicity (ORadj = 0.30, 95 % CI 0.13-0.68), and overweight (ORadj = 0.11, 95 % CI 0.05-0.23) or obese (ORadj = 0.03, 95 % CI 0.02-0.07) status at diagnosis and positively associated with time elapsed since diagnosis (ORadj = 1.19/year, 95 % CI 1.04-1.36). Women prescribed aromatase inhibitors were 46 % less likely to gain weight compared to women prescribed selective estrogen-receptor modulators (ORadj = 0.54, 95 % CI 0.31-0.93). The risk of weight gain was positively associated with smoking at diagnosis (ORadj = 2.69, 95 % CI 1.12-6.49) although this was attributable to women who subsequently quit smoking. Conclusions: Postdiagnosis weight gain is common and complex and influenced by age, ethnicity, weight, smoking status, time elapsed since diagnosis, and endocrine-modulating therapy. Implications for cancer survivors: Weight gain continues to be a concern following a diagnosis of breast cancer. Factors influencing this weight gain include age, ethnicity, weight, smoking status, time elapsed since diagnosis, and endocrine-modulating therapy. Effective weight management strategies are needed for this population of women. © 2014 Springer Science+Business Media New York.

Obesity is a poor prognostic factor and is negatively related to quality of life (QOL) in breast cancer survivors. Exercise and Nutrition to Enhance Recovery and Good Health for You is the largest weight loss trial completed among cancer survivors. Percent losses in body weight with an intensive group-based intervention versus an attention control were 6.0 versus 1.5 % (p < 0.0001) and 3.7 versus 1.3 % (p < 0.0001) at 12 and 24 months, respectively. ENERGY also was designed to answer the research question: Does weight loss significantly improve vitality and physical function (key components of QOL)? 692 breast cancer survivors (BMI: 25–45 kg/m2) at 4 US sites were randomized to a year-long intensive intervention of 52 group sessions and telephone counseling contacts versus a non-intensive (control) of two in-person counseling sessions. Weight, self-reported QOL, and symptoms were measured semi-annually for two years. Significant decreases in physical function and increases in symptoms were observed among controls from baseline to 6 months, but not in the intervention arm, −3.45 (95 % Confidence Interval [CI] −6.10, −0.79, p = 0.0109) and 0.10 (95 %CI 0.04, 0.16, p = 0.0021), respectively. Improvements in vitality were seen in both arms but trended toward greater improvement in the intervention arm −2.72 (95 % CI −5.45, 0.01, p = 0.0508). These differences diminished over time; however, depressive symptoms increased in the intervention versus control arms and became significant at 24 months, −1.64 (95 % CI −3.13, −0.15, p = 0.0308). Increased QOL has been reported in shorter term diet and exercise trials among cancer survivors. These longer term data suggest that diet and exercise interventions improve some aspects of QOL, but these benefits may diminish over time.