Body composition is associated with risk of toxicity-induced modifications of treatment in women with stage I-IIIB breast cancer receiving chemotherapy.

PURPOSE: Initial dose of chemotherapy is planned based on body surface area, which does not take body composition into account. We studied the association between fat mass (kg and relative to total body weight) as well as lean mass (kg and relative to total body weight) and toxicity-induced modifications of treatment in breast cancer patients receiving chemotherapy. METHODS: In an observational study among 172 breast cancer patients (stage I-IIIB) in the Netherlands, we assessed body composition using dual-energy X-ray scans. Information on toxicity-induced modifications of treatment, defined as dose reductions, cycle delays, regimen switches, or premature termination of chemotherapy, was abstracted from medical records. Adjusted hazard ratios and 95% confidence intervals (95% CI) were calculated to assess associations between body composition and the risk of toxicity-induced modifications of treatment. RESULTS: In total, 95 out of 172 (55%) patients experienced toxicity-induced modifications of treatment. Higher absolute and relative fat mass were associated with higher risk of these modifications (HR 1.14 per 5 kg; 95% CI 1.04-1.25 and HR 1.21 per 5%; 95% CI 1.05-1.38, respectively). A higher relative lean mass was associated with a lower risk of modifications (HR 0.83 per 5%; 95% CI 0.72-0.96). There was no association between absolute lean mass and risk of toxicity-induced modifications of treatment. CONCLUSIONS: A higher absolute and a higher relative fat mass was associated with an increased risk of toxicity-induced modifications of treatment. Absolute lean mass was not associated with risk of these treatment modifications, while higher relative lean mass associated with lower risk of modifications. These data suggest that total fat mass importantly determines the risk of toxicities during chemotherapy in breast cancer patients.

Changes in Circulating Levels of 25-hydroxyvitamin D3 in Breast Cancer Patients Receiving Chemotherapy.

Cancer treatments, toxicities and their effects on lifestyle, may impact levels of vitamin D. The aim of this study was to determine serum 25-hydroxyvitamin D3 (25(OH)D3) levels before, directly after and 6 months after chemotherapy in breast cancer patients (n = 95), and a comparison group of women (n = 52) not diagnosed with cancer. Changes in 25(OH)D3 levels over time were compared using linear mixed models adjusted for age and season of blood sampling. Before start of chemotherapy, 25(OH)D3 levels were lower in patients (estimated marginal mean 55.8 nmol/L, 95% confidence interval (95%CI) 51.2-60.4) compared to the comparison group (67.2 nmol/L, 95%CI 61.1-73.3, P = 0.003). Directly after chemotherapy, 25(OH)D3 levels were slightly decreased (-5.1 nmol/L, 95%CI -10.7-0.5, P = 0.082), but ended up higher 6 months after chemotherapy (10.9 nmol/L, 95%CI 5.5-16.4, P < 0.001) compared to pre-chemotherapy values. In women without cancer, 25(OH)D3 levels remained stable throughout the study. Use of dietary supplements did not explain recovery of 25(OH)D3 levels after chemotherapy. We reported lower 25(OH)D3 levels in breast cancer patients, which decreased during chemotherapy, but recovered to levels observed in women without cancer within 6 months after chemotherapy. Suboptimal 25(OH)D3 levels in the majority of the participants highlight the relevance of monitoring in this vulnerable population.

Associations of Abdominal Skeletal Muscle Mass, Fat Mass, and Mortality among Men and Women with Stage I-III Colorectal Cancer.

BACKGROUND: The associations of abdominal skeletal muscle mass index (SMI), visceral and subcutaneous adipose tissue (VAT and SAT, respectively), and mortality among patients with stage I-III colorectal cancer may differ for men and women, but only few studies stratified their data into men and women. We investigated associations of abdominal SMI, VAT, and SAT with overall mortality among men and among women with stage I-III colorectal cancer. METHODS: SMI, VAT, and SAT were assessed from abdominal CT images for 1,998 patients with stage I-III colorectal cancer diagnosed between 2006 and 2015. Restricted cubic splines (RCS) were used to investigate associations of SMI, VAT, and SAT with overall mortality. RESULTS: Average age of the participants was 67.9 ± 10.6 years and 58% were men. During a median follow-up of 4.3 years, 546 (27%) patients died. Among men, the association of SMI and mortality was statistically significant in a nonlinear way in the RCS analyses, with lower SMI levels associated with higher mortality. SMI was not associated with mortality among women. SAT was associated with mortality in a nonlinear way for men and for women, with lower SAT levels being associated with higher mortality. VAT was not significantly associated with mortality in men or women. CONCLUSION: Associations of abdominal skeletal muscle mass with mortality among patients with colorectal cancer were not the same for men and for women. IMPACT: This study stresses the importance for more attention on sex-related differences in body composition and cancer outcomes.