Prognostic factors of primary resected retroperitoneal soft tissue sarcoma: Analysis from a single asian tertiary center and external validation of gronchi's nomogram

Background Surgery is the potentially curative treatment for retroperitoneal sarcoma (RS), but complete resectability is frequently a challenge. This study aimed to characterize the clinical features, prognostic factors and treatment outcomes. Methods A cohort of 144 patients with RS was surveyed retrospectively from January 1st, 2000 to July 30th, 2011. The prognostic influence of clinicopathological characteristics as well as treatments on local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and overall survival (OS), were examined by univariate and multivariate analyses. A histology-specific nomogram developed by Gronchi et al was used for validation. Results Liposarcoma, leiomyosarcoma, and malignant peripheral sheath tumor (MPNST) were the most common histologies (70%). Multivariate analysis revealed FNCLCC tumor grade was the most significant prognostic factor for OS (P = 0.001) and DMFS (P < 0.001) and complete resection was the only significant prognostic factor for LRFS (P = 0.043). Incomplete resection of grade 3 tumor was significantly associated with a worse OS. Despite some differences in characteristics between our patients and Gronchi's cohort, external validation of Gronchi's nomogram demonstrated excellent concordance in predicting survival. Conclusions Our study demonstrated tumor grade and surgical margins had significant prognostic influence and the Gronchi's nomogram has an excellent applicability in predicting survival of STS patients.