CACHEXIO: Evaluation of body composition changes and immunotherapy in patients with metastatic cancer.

Abstract

209 Background: Given body composition predicts toxicity for patients receiving cytotoxic chemotherapy, we explored changes in body composition and biomarkers as predictors of immune-related adverse events (irAEs) and health care utilization. Methods: We conducted a longitudinal study of patients with metastatic solid tumor receiving immunotherapy (07/2014-10/2017). Eligible patients had a computed tomography (CT) scan prior to first-line immunotherapy with at least two additional CT scans at three, six or nine months after immunotherapy initiation. We analyzed body composition using cross-sectional CT scans at the third lumbar vertebra. We utilized mixed effect linear regression models to assess longitudinal changes in body composition (weight, skeletal muscle, total adipose). We examined associations of baseline body composition and biomarkers (albumin, neutrophil-lymphocyte ratio (NLR)) with the incidence of irAEs and healthcare utilization (hospitalizations/ED visits) using logistic regression. Results: Of 140 patients treated with immunotherapy, 61 met inclusion criteria. The majority (80%) received prior chemotherapy and the most common malignancies included lung (26%), head and neck (20%), and melanoma (20%). We found that one-third (n=19) experienced an irAE and colitis (53%) was the most common irAE. Patients experienced substantial weight loss over time (B= -1.88, p<0.001) with a decrease both in skeletal muscle (B= -3.08, p=0.001) and total adipose tissue (B =-50.44, p<0.001). We found greater skeletal muscle at baseline was associated with lower risk of health care utilization (OR 0.98, 95% CI: 0.965-0.998, p=0.03). We observed no association with biomarkers and/or body composition variables with irAEs or health care utilization. Conclusions: Patients with metastatic cancer receiving immunotherapy lose weight including skeletal muscle and adipose tissue. Aside from higher baseline skeletal muscle predicting less health care utilization, we did not observe any other associations between body composition changes and irAEs or health care utilization.