Research Grants Awarded
Determinants of Weight Gain in Women with Early Stage Breast Cancer
RISK and Prevention, Epidemiology
Background. Weight gain after breast cancer diagnosis is common, occurring in 50-95% of early stage patients undergoing adjuvant chemotherapy, and has been associated with poorer outcome. Women who gain approximately 15 lbs are 1.5 times more likely to relapse and die compared to those who maintain their weight. Important contributors to this weight gain may include treatment-related declines in ovarian function and increases in cortisol due to physical and psychological stress. Hypothesis. Since sex hormones and glucocorticoids regulate body weight, we hypothesize that they play a role in treatment-induced weight gain, and that complex interactions exist with genetic susceptibility, lifestyle, and psychosocial factors. We hypothesize greater gains in patients with 1) greater declines in sex hormones and/or increases in cortisol; 2) genetic polymorphisms associated with reduced sex hormone production; 3) positive energy balance; and 4) greater levels of psychosocial stress. Aims . We will examine post-diagnostic weight change and: 1) changes in sex hormone and cortisol levels; 2) genetic polymorphisms in sex hormone pathways; 3) energy intake, physical activity, and psychosocial factors; and 4) characteristics of the cancer and treatments received. As an exploratory aim, we will examine weight change and potential interactions between hormonal changes, genetic polymorphisms, and the factors noted in Aims 3 and 4. Design. We will conduct a prospective study of weight gain in 290 patients, aged 35 to 75, with non-metastatic disease (Stage I to IIIA). With consent, we will collect serial biospecimens and survey data, to determine hormone levels and genetic polymorphisms, and to assess menopausal status, anthropometry, diet, physical activity, and psychosocial factors at baseline, 6, and 12 months. These factors will be evaluated in relation to weight change. The long-term aim will be to follow these women prospectively to examine cancer recurrence and mortality. Benefits. This study will be the first to comprehensively examine predictors and modulators of post-diagnostic weight gain in women with breast cancer using a multidisciplinary approach encompassing hormonal changes, genetic polymorphisms, and psychosocial factors. The outcome of this research will shed light on why so many women suffer weight gain after breast cancer, and will help guide the development of interventions targeted at preventing weight gain.
Weight gain after breast cancer is common, occurring in up to 95% of patients whose cancer is detected early and who receive chemotherapy during treatment. A gain of approximately 15 lbs has been associated with a 50% greater likelihood of having the cancer recur and a 60% increased likelihood of dying compared to women who maintain their weight. Reasons for this weight gain are poorly understood and have not been carefully studied. One reason for the weight gain may be that chemotherapy shuts down the ovaries, thereby reducing sex hormone production. While this is expected to lower breast cancer recurrence, it is also associated with weight gain and increased body fat, which is in turn, associated with higher levels of sex hormone production. In addition, the physical and psychological stress of having breast cancer can increase cortisol levels, a stress hormone, which can further turn off the ovaries, and has itself been associated with increased dietary intake and weight gain. Since sex hormones and cortisol influence overall body weight, we believe that changes in sex hormone and/or cortisol levels may affect how much weight is gained after breast cancer. We think that this relationship may be affected by a woman’s genetic makeup, her diet and level of physical activity, and her psychological and social well-being. The primary goal of this study will be to examine weight change after breast cancer in relation to changes in sex hormone and cortisol levels. The study will involve 290 women aged 35 to 75 years who are diagnosed with early breast cancer. These women will be followed for 1 year. The long-term aim will be to determine if weight gain and the factors that cause it are related to breast cancer recurrence and overall survival. We think that patients with greater declines in sex hormones and/or increases in cortisol will gain the most weight. The study also plans to examine other factors that can contribute to weight gain, including fatigue, characteristics of the cancer, and treatments received. This study will be the first to comprehensively examine hormonal changes, genetic makeup, diet, physical activity, and psychological and social well-being as reasons for weight gain in women with breast cancer. The outcome of this research will shed light on why so many women suffer weight gain after breast cancer, and help identify those who are most susceptible so that they can be targeted for interventions to prevent weight gain .