Association between preoperative skeletal muscle mass depletion and poor relapse-free survival in patients with gastrointestinal stromal tumors after complete resection

Abstract

ObjectivesThe aim of this study was to investigate the predictive effects of skeletal muscle mass (SMM) depletion on relapse risk in patients who had undergone complete surgical resection for primary resectable gastrointestinal stromal tumors (GISTs). MethodsThis retrospective study comprised 445 enrolled patients with primary resectable GISTs who had undergone surgical treatment between January 2013 and January 2021. The lumbar skeletal muscle index (SMI) was assessed using abdominal computed tomography images taken within 7 d preoperatively. Univariate and multivariate Cox regression analyses were performed to identify independent risk factors for nomogram construction. Predictive accuracy and discriminative ability were measured using the concordance index (C-index). ResultsThree- and 5-y relapse-free survival (RFS) rates for patients in the low SMI group were significantly worse than those in the high SMI group (81.3 and 75.4% versus 92.3 and 91.6%, respectively; P < 0.001). In stratification analysis using modified National Institutes of Health criteria, high-risk patients with low SMI showed significantly shorter RFS (P = 0.001). Multivariate analysis indicated that tumor size, tumor location, mitotic rates, the platelet-to-lymphocyte ratio, the prognostic nutritional index, and SMM depletion were independent prognostic factors for RFS (P < 0.05). These six variables were selected for nomogram construction, which showed superior discrimination with a C-index of 0.82. ConclusionsThere was a significant association between preoperative SMM depletion and a high risk for relapse in patients who had undergone complete resection for primary resectable GISTs, especially in patients with high-risk GIST. Our simple, practical, novel nomogram intuitively predicted RFS in these patients.