Abstract
Background
Low skeletal muscle mass has been increasingly recognized as a negative prognostic factor in oncology. According to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2), sarcopenia is defined as a progressive and generalized skeletal muscle disorder characterized by the loss of muscle strength and muscle mass, which can lead to impaired physical performance. This study aimed to investigate whether baseline low muscle mass and dynamic changes in muscle mass during immunotherapy could predict treatment response and survival in patients with metastatic renal cell carcinoma (mRCC) treated with Nivolumab.
Patients and methods
This retrospective cohort study included 50 mRCC patients (35 men, 15 women; mean age 59.1 ± 10.2 years) who received Nivolumab between 2019 and 2022 and underwent abdominal computed tomography (CT) before and during treatment. Muscle mass was assessed by calculating the skeletal muscle index (SMI) at the third lumbar vertebra using standard Hounsfield unit thresholds (-29 to +150 HU). Treatment response was evaluated according to immune Response Evaluation Criteria in Solid Tumors (iRECIST). Overall survival (OS) and progression-free survival (PFS) were analyzed using Kaplan–Meier curves and Cox regression models.
Results
Low muscle mass was identified in 60% of patients and was significantly associated with multiple organ metastases (p = 0.003). Patients with baseline low muscle mass or a negative change in SMI during treatment demonstrated poorer treatment response (p = 0.027 and p = 0.021, respectively). Both OS and PFS were significantly shorter in patients with low muscle mass and those with declining muscle mass during treatment.
Conclusions
Pre-treatment low muscle mass and muscle mass decline during immunotherapy were independently associated with inferior survival and treatment response in mRCC patients receiving Nivolumab. CT-based muscle mass assessment may serve as an imaging-based prognostic biomarker in this population.