A longitudinal mixed methods study on changes in body weight, body composition, and lifestyle in breast cancer patients during chemotherapy and in a comparison group of women without cancer: study protocol.

BACKGROUND: More than 60% of women diagnosed with early stage breast cancer receive (neo)adjuvant chemotherapy. Breast cancer patients receiving chemotherapy often experience symptoms such as nausea, vomiting and loss of appetite that potentially affect body weight and body composition. Changes in body weight and body composition may detrimentally affect their quality of life, and could potentially increase the risk of disease recurrence, cardiovascular disease and diabetes. To date, from existing single method (quantitative or qualitative) studies is not clear whether changes in body weight and body composition in breast cancer patients are treatment related because previous studies have not included a control group of women without breast cancer. METHODS: We therefore developed the COBRA-study (Change Of Body composition in BReast cancer: All-in Assessment-study) to assess changes in body weight, body composition and related lifestyle factors such as changes in physical activity, dietary intake and other behaviours. Important and unique features of the COBRA-study is that it used I) a "Mixed Methods Design", in order to quantitatively assess changes in body weight, body composition and lifestyle factors and, to qualitatively assess how perceptions of women may have influenced these measured changes pre-, during and post-chemotherapy, and II) a control group of non-cancer women for comparison. Descriptive statistics on individual quantitative data were combined with results from a thematic analysis on the interviews- and focus group data to understand patients' experiences before, during and after chemotherapy. DISCUSSION: The findings of our mixed methods study, on chemotherapy treated cancer patients and a comparison group, can enable healthcare researchers and professionals to develop tailored intervention schemes to help breast cancer patients prevent or handle the physical and mental changes they experience as a result of their chemotherapy. This will ultimately improve their quality of life and could potentially reduce their risk for other co-morbidity health issues such as cardiovascular disease and diabetes.