Body composition in patients with metastatic renal cell carcinoma receiving ipilimumab plus nivolumab.

e16517 Background: Body composition (comp) is an increasingly recognized prognostic indicator in patients with cancer, but there are limited data regarding body comp measurements in patients with metastatic renal cell carcinoma (mRCC) treated with immune checkpoint inhibitors. The goal of this study was to assess baseline body comp measurements and rates of sarcopenia in patients with mRCC receiving ipilimumab + nivolumab (ipi/nivo) as first-line systemic therapy and examine potential associations with overall survival (OS). Methods: We conducted a retrospective analysis of all patients with mRCC treated with first line ipi/nivo at Duke Cancer Center prior to June 1, 2021, who had a CT scan within 6 weeks of ipi/nivo initiation. CT images were segmented and measured with Automatic Body composition Analyser using Computed tomography image Segmentation (ABACS) software (Voronoi Health Analytics). Areas of skeletal muscle (SM), subcutaneous fat (SF), and visceral fat (VF) at the level of the 3rd lumbar vertebra were measured and converted to indices by dividing by height (m 2 ) (Area SMI, SFI, VFI). Volumes of SM, SF, and VF between the 1st and 5th lumbar vertebrae were measured and converted to indices by dividing by the height of the measured slab (Volume SMI, SFI, VFI). Sarcopenia was defined as SMI < 55cm 2 /m 2 in men and < 39cm 2 /m 2 in women based on prior studies. Medical records were retrospectively reviewed to identify demographic and oncologic details. Effects of body comp measures on overall survival were assessed using Cox proportional hazard models, which were adjusted for IMDC risk, age, and sex. Results: 104 patients met study criteria and had an analyzable baseline CT scan. Median age was 62 (range 37 – 81). 71% of patients were male. Median body mass index (BMI) was 27.2 (range 17.8 – 43.6). IMDC risk score was 12% favorable, 63% intermediate, 20% poor, and 5% unknown. Median follow up time was 19.98 months. Median survival was 39.79 months (95% CI 27.01, NA). 1-year survival rate was 0.81 [95% CI 0.73, 0.89] and 2-year survival rate was 0.68 [95% CI 0.59, 0.79]. 77 of 104 patients (74%) met the definition of sarcopenia prior to treatment. No body comp measurements were associated with OS. Effects of body comp measurements on overall survival are shown in table 1. Conclusions: Baseline body comp measures were not associated with OS in a population of patients with mRCC receiving ipi/nivo as first-line systemic therapy. Changes in body comp over time may instead be of interest as potential biomarkers for OS in patients with mRCC receiving ipi/nivo. [Table: see text]