Changes in body composition as a result of chemotherapy : Comparing women with and without breast cancer

Because of the improved survival rate, both short term and long term adverse effects of breast cancer treatment have become increasingly important. Body weight and body composition before, during, and after chemotherapy may influence side effects during treatment and survival. The aims of this thesis were to assess among stage I-IIIB breast cancer patients: 1) the association between pre-treatment body composition and dose-limiting toxicities during chemotherapy, 2) potential changes in body weight and body composition during and after chemotherapy compared to changes in age-matched women without cancer in the same time period, and 3) dietary intake during chemotherapy compared to age-matched women without cancer in the same time period. Chapter 2 describes the association between pre-treatment body composition and dose-limiting toxicities during chemotherapy. Data from 172 breast cancer patients who participated in the COBRA-study were analysed. Body composition was measured using a total body Dual Energy X-ray Absorption (DEXA) scan. Information regarding dose-limiting toxicities was abstracted from medical records. A higher BMI (kg/m2) and a higher fat mass (kg and percentage) were associated with an increased risk of dose-limiting toxicity, while lean body mass (kg) was not associated with risk of toxicities. Chapter 3 presents the findings of a meta-analysis on changes in body weight during chemotherapy in breast cancer patients. The meta-analysis showed an overall gain in body weight of 2.7 kg (95% CI: 2.0-3.3) during chemotherapy, with a high degree of heterogeneity (I2= 94.2%). Weight gain in breast cancer patients was more pronounced in papers published before 2000 and studies including cyclophosphamide, methotrexate and 5-fluorouracil as chemotherapy regime. Chapter 4 describes changes in body weight and body composition during and after chemotherapy. Data from 145 patients and 121 women of an age-matched comparison group, participating in the COBRA-study were analysed. Body composition was measured using DEXA-scan at three time points during the study period. For the patient group, these tie points were: before start of chemotherapy, shortly after chemotherapy, and 6 months after chemotherapy. For the comparison group these measurements were conducted over a similar time frame: baseline, 6 months after baseline, and 12 months after baseline. In addition, we identified determinants of changes in body weight and body composition. Shortly after chemotherapy, patients had a significantly higher body weight, BMI, and lean body mass than women in the comparison group, while fat mass was similar. Six months after chemotherapy no differences in body weight or body composition were observed between the patient and comparison group. A younger age, better appetite during chemotherapy, and an ER-receptor negative tumour were associated with greater changes in body weight over time. A younger age and better appetite during chemotherapy were associated with greater changes in fat mass over time, while the only determinant associated with greater changes in lean body mass over time was a better appetite during chemotherapy. Chapter 5 describes the dietary intake and food groups before and during chemotherapy of breast cancer patients compared with women without cancer. In addition we assessed the association between symptoms and energy intake. Data from 117 breast cancer patients and 88 women without breast cancer who participated in the COBRA-study were used. Habitual dietary intake before chemotherapy was assessed using a food frequency questionnaire. Two 24-hr dietary recalls were used to assess actual dietary intake during chemotherapy for patients and within 6 months for the comparison group. Shortly after the 24-hr dietary recall, participants filled out questionnaires about symptoms. Before chemotherapy, dietary intake was similar for both groups. During chemotherapy, breast cancer patients reported significantly lower total energy, total fat, total protein, and alcohol intake than women without cancer, which could be explained by a lower intake of specific food groups. Overall results from this thesis suggest that pre-treatment fat mass is associated with dose-limiting toxicities during chemotherapy. Weight gain during chemotherapy appeared to be more modest than we expected based on literature and changes in body composition during chemotherapy consist mainly of an increase in lean body mass, which is only temporary and returned to baseline within 6 months after chemotherapy. A higher appetite during chemotherapy was associated with changes in body weight and body composition. A younger age at diagnosis was associated with greater changes in body weight and fat mass, but not with changes in lean body mass. In addition, an ER-receptor negative tumour was associated with greater changes in body weight, but not with changes in fat mass or lean body mass. During chemotherapy women with breast cancer have a lower intake of energy, fat, protein and alcohol compared to age-matched women without cancer, which was expressed in a lower intake of specific food groups. The results of this thesis do not suggest that dietary intake is associated with weight gain during chemotherapy.