Low computed tomography (CT)-determined muscle mass, commonly determined with height-adjusted muscle indexes (MIs), predicts worse survival in several cancers and has been suggested as a prognostic assessment tool. Although several MIs measured at the level of the 3rd lumbar vertebra (L3) are commonly used, it remains unestablished how different L3-determined MIs perform in survival prognostication compared to each other. The objective of this study was to investigate the performance of different MIs for survival prognostication in renal cell carcinoma (RCC).
We retrospectively enrolled 214 consecutive patients with RCC. We determined three L3-MIs (psoas muscle index (PMI), psoas muscle index and erector spinae index (PMI+ESI), and whole skeletal muscle index (SMI)) from preoperative CT scans. Categorization of those with low and normal muscle mass was based on the Youden Index sex-specific MI cut-offs. We determined sensitivity, specificity, and accuracy metrics for predicting 1-year, 5-year, and overall survival (OS) using Cox regression models.
Low PMI, PMI+ESI, and SMI significantly predicted decreased 1-year, 5-year, and OS in uni- and multivariate models. PMI+ESI and SMI were more accurate than PMI in males, and PMI and PMI+ESI were more accurate than SMI in females in the prediction of 1-year survival. However, there were no differences in accuracies between MIs in 5-year and OS prediction.
PMI+ESI performed well overall in short-term prognostication, but there were no differences between the MIs in long-term prognostication. We recommend the use of PMI+ESI for muscle evaluation, particularly when SMI cannot be evaluated.
Acta oncologica (Stockholm, Sweden). 2024 May 14*** epublish ***
Oona Janhunen, Otto Jokelainen, Robin Peltoniemi, Timo K Nykopp, Otso Arponen
Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland., Clinical Pathology and Forensic Medicine, Institute of Clinical Medicine, School of Medicine, University of Eastern Finland, Kuopio, Finland; Department of Clinical Pathology, Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland., Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland; Department of Radiology, Tampere University Hospital, Tampere, Finland., Surgery, Institute of Clinical Medicine, School of Medicine, University of Eastern Finland, Kuopio, Finland; Department of Urology, Division of Surgery, Kuopio University Hospital, Kuopio, Finland., Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland and Department of Oncology, Tays Cancer Centre, Tampere University Hospital, Tampere, Finland. .