Study Finds Breast Cancer Survivors Gain More Weight Than Cancer-Free Women
A prospective study examining weight gain in breast cancer survivors compared with cancer-free women from a familial risk cohort has found that, overall, breast cancer survivors gained significantly more weight than cancer-free women of the same age and menopausal status. According to the study findings, in the first 5 years post treatment, survivors gain weight at a faster rate than cancer-free women, particularly after chemotherapy and statin use but not after hormone therapy alone. The findings provide support for the development of weight gain interventions for young breast cancer survivors with a familial risk, said the study authors. The study by Gross et al is published in Cancer Epidemiology, Biomarkers & Prevention.
Study Methodology
The researchers recruited 303 breast cancer survivors and 307 age- and menopausal status–matched cancer-free women from the Breast and Ovarian Surveillance Service (BOSS) cohort study—an ongoing prospective study consisting of women and men with a familial risk for breast and/or ovarian cancer, including BRCA1/2-mutation carriers— recruited between 2005 and 2013. Women enrolled in the cohort who had completed a baseline questionnaire and at least one follow-up questionnaire (administered every 3 or 4 years) were included in the study.
In addition, women had to have either a family history of breast or ovarian cancer, a documented deleterious BRCA1/2 mutation, or a diagnosis of breast cancer at age ≥ 40 years and have provided height and weight on baseline questionnaire (n = 911). Survivors were eligible if they had a personal history of breast cancer (ductal carcinoma in situ or stage I to III breast cancer) treated with surgery at any time prior to baseline (n = 303). Eligible cancer-free women based on the study inclusion criteria were frequency matched to survivors on age and menopausal status (n = 307), to ensure a similar distribution of these strong confounding factors between the two groups.
Of the 303 breast cancer survivors, 179 had received treatment within 5 years of completing the questionnaire, and 123 had received treatment more than 5 years before completing the questionnaire. About 50% reported receiving chemotherapy, and about two-thirds reported receiving hormonal therapy. Sixty-eight percent of the breast cancer survivors and 72% of the cancer-free women had reported baseline physical activity that met the American Heart Association recommendations.
Study Results
Overall, breast cancer survivors gained significantly more weight (ß = 3.06 pounds; 95% confidence interval [CI] = 0.94–5.17) than cancer-free women. Significant weight gain was observed in survivors diagnosed less than 5 years prior to baseline (ß = 3.81 pounds; 95% CI = 1.22–6.29) and women with estrogen receptor–negative tumors (ß = 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-free women (odds ratio = 2.10; 95% CI = 1.21–3.63).
Weight gain was even greater among survivors who took statins while undergoing chemotherapy treatment (P = .01).
“Our study showed that women diagnosed with breast cancer and those who received chemotherapy to treat their breast cancer gained more weight within the first 5 years of diagnosis and treatment than cancer-free women,” said Kala Visvanathan, MD, MHS, a coauthor of the study and Associate Professor of Epidemiology at the Johns Hopkins Bloomberg School of Public Health and Director of the Clinical Cancer Genetics and Prevention Service at the Sidney Kimmel Comprehensive Cancer Center, in a statement. “This study highlights the need for physicians and their patients, including those with a family history of the disease, to pay closer attention to weight gain during and after treatment. Longer follow-up is needed to confirm the persistence of weight gain in breast cancer survivors and understand the metabolic changes that may be occurring.”
Dr. Visvanathan is the corresponding author of this study.
Funding for this study was provided by the Breast Cancer Research Foundation and the National Institutes of Health. The study authors reported no potential conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
