Comparison of prognostic reliability of TNM staging systems version 7/8 and SARCULATOR in primary localized liposarcomas of the extremity or trunk wall.

Abstract

e23529 Background: The oncological staging system should provide meaningful information regarding the patients’ prognosis. For soft tissue sarcomas, available staging systems include AJCC version 8, AJCC version 7, and nomogram-based approaches such as SARCULATOR (which additionally includes age and subtype). This work compares these systems using a group of extremity/trunk wall cases of liposarcoma (LPS). Methods: We have included all (N = 147) consecutive, newly diagnosed LPS patients treated in our institution between 2010 and 2021. We have excluded atypical lipomatous tumors. Patients’ and tumor characteristics were collected, and AJCC staging and SARCULATOR risk assessment were performed. Appropriate Cox proportional hazard models were fitted. The results were compared using the concordance index, Akaike information criterion (AIC), and partial likelihood ratio (PLR) test for non-nested Cox models. Results: In this group, 81 (55.1%) patients were male; the mean age in the group was 54 years (SD:16). Most tumors (83%) were localized on the lower extremity, with 8.8% on the upper extremity and 8.2% on the trunk. 66% of cases were myxoid LPS, 17.7% - dedifferentiated and 16.3% - pleomorphic. The median tumor size was 12 cm (IQR 9 – 18). Patients’ prognostic groups are summarized in Table. The median follow-up was 43 months (95%CI:38-51). The median overall survival (OS) was not reached. The 5-year survival rate was 68% (95%CI:62-75). The concordance for AJCC version 7, AJCC version 8, and SARCULATOR were respectively 0.625, 0.705, and 0.778. The AIC in the same order were: 311, 301, 274. The PLR test showed that AJCC version 8 fits better than AJCC version 7 (p for superiority = 0.036) while SARCULATOR fits better than AJCC version 8 (p for superiority = 0.028). Conclusions: New staging systems improve in better predicting patients outcome. In rare diseases such as sarcomas, it is crucial to have access to more personalized nomograms such as SARCULATOR.[Table: see text]