Muscle matters: Skeletal muscle index and body mass index impact on complications and survival in renal cancer.

Objective: The objective of this study is to independently assess skeletal muscle index (SMI) and body mass index (BMI) as prognostic determinants for renal cell carcinoma (RCC) and investigate their correlation with surgical outcomes. Patients and methods: A retrospective cohort study of 524 RCC patients diagnosed between August 2010 and July 2018 was conducted using data from the Zealand University Hospital Renal Cancer Database in Denmark. Patient information was extracted from electronic patient records and the National Cancer Registry and encompassed demographics, clinical factors, tumour characteristics and surgical details. SMI was calculated from a single third lumbar vertebra (L3) axial computed tomography (CT) image via CoreSlicer software and classified into high using gender-specific thresholds. Primary outcomes focused on complications within 90 days as well as survival outcomes, and their relation with both SMI and BMI. Multivariable analysis assessed SMI's independent prognostic significance in RCC. Results: Among 524 patients, 18.5% experienced complications, with high SMI correlating significantly ( Conclusions: Higher SMI increases the risk of postoperative complications, yet it significantly improves overall survival rates. Different BMI categories lack RCC prognostic significance. The increasing incidence in RCC calls for the use of CT scan to assess SMI and aid treatment planning in patients who might benefit from preoperative interventions.