Prognostic Models and Signatures in Retroperitoneal Sarcoma

CINSARC (the Complexity Index in SARComas) is a transcriptomic profile that independently forecasts the risk of metastasis in soft tissue sarcoma patients. This study aimed to (1) deliver the first standalone validation of CINSARC in a group of patients with retroperitoneal sarcoma (RPS) and (2) investigate if integrating CINSARC could improve the predictive accuracy of the Sarculator model. The Istituto Nazionale Tumori (INT) group comprised patients with primary localized retroperitoneal sarcoma (RPS) who underwent curative surgery between 2011 and 2015, as part of the SARCOMICS study. Patients were divided into two categories based on their CINSARC status: low-risk (C1) and high-risk (C2). The main outcomes measured were overall survival (OS) and disease-free survival (DFS), with multivariable Cox models used for analysis. The accuracy of the Sarculator was evaluated based on its discriminatory power (using Harrell’s C-index) and calibration (assessed via calibration plots and the Brier score), both before and after incorporating CINSARC data. The study confirmed that CINSARC serves as a prognostic marker for OS and DFS in patients with primary RPS who received surgical treatment. However, adding CINSARC to the Sarculator did not enhance its discrimination or calibration, indicating that its integration may not offer additional clinical advantages.