The role of body composition in neurological and hematologic toxicity in breast cancer patients undergoing neoadjuvant chemotherapy. The COMBOTOX study

Abstract Purpose: Neoadjuvant chemotherapy (NAC) has a well estabilished role in locally advanced or chemoresponsive breast cancers (BC). Chemotherapic regimens are effective when patients receive the optimal doses. Toxicities are common in overweight/obese patients but may occur also in normal weight counterparts. This lead to delays, reductions or discontinuation of treatment, with impact on outcomes. Current dosing is based on body weight and predicted Body Surface Area (BSA). These parameters do not take into consideration the individual variations of fat mass (FM) and fat-free mass (FFM) that affect pharmacokinetics. Assessment of body composition (BoCo), rather than Body Mass Index (BMI), could help to better plan chemotherapy and reduce drug-related toxicities. Our aim was to analyze the correlations between body weight, anthropometric measures, BoCO and toxicities related to NAC in non metastatic BC patients. Methods: This is a retrospective observational cohort study that includes 120 consecutive BC patients undergoing NAC, enrolled between May 2018 and December 2020. All patients received an evaluation of anthropometric parameters (height, weight, waist and hip circumference, BMI) and an assessment of BoCo using Segmental Multi Frequency-Bioelectrical Impedance Analysis. Results: A logistic regression models confirmed that a higher FM was associated with a higher rate of neurological and hematological toxicities in protocols containing Platinum. Moreover, patients with a low FFM% have a higher risk for hematologic toxicity in protocols containing Platinum. Conclusion: A routinary assessment of BoCo, in addition to evaluation of anthropometric measures and BMI, could allow to personalize chemotherapy doses, in order to reduce chemotherapy-related toxicities.