(P 304) MANAGEMENT OF RECURRENT RETROPERITONEAL SARCOMAS: A RETROSPECTIVE STUDY FROM A TERTIARY CANCER CENTER.

Objective: Retroperitoneal sarcoma (RPS) is a rare and complex malignancy, requiring specialized multidisciplinary care. While significant progress has been made in managing primary RPS, limited literature exists on the outcomes of recurrent RPS (Rec RPS). This study audits the oncological outcomes of Rec RPS at a leading sarcoma referral center in India, addressing gaps in the existing literature

Methods: A retrospective analysis was performed on patients with Rec RPS who underwent surgery between January 2011 and December 2024. . Surgical procedures included compartmental resections, en bloc resections, vascular resections, and tumor excisions. Histopathological assessment, organ invasion analysis, and adjuvant therapy utilization were recorded. Kaplan-Meier estimates evaluated overall survival (OS) and disease-free survival (DFS), with statistical significance assessed via log-rank test and Cox regression analysis.

Results: The study analyzed 288 patients, with 188 undergoing primary surgery at an oncological center and 100 previously operated elsewhere. Recurrence rates were significantly higher (93.9%) in patients who had inadequate surgery at non-oncological centers compared to those initially treated at specialized centers (39.1%). Histological subtypes included dedifferentiated liposarcoma (DDLPS) (32.3%), well-differentiated liposarcoma (WDLPS) (23.9%), and leiomyosarcoma (LMS) (23.4%). Histopathologic organ invasion (HOI) was identified in 47% of recurrent cases, with colon, kidney, and small intestine being most affected. Median OS for primary RPS was 137.1 months, while Rec RPS had significantly reduced survival at 42.48 months (p=0.002). DFS was notably lower in recurrent cases, particularly in patients who had undergone prior inadequate surgery. Patterns of recurrence impacted survival outcomes, with distant recurrence and sarcomatosis associated with worse prognosis. On multivariate analysis, factors influencing recurrence included margin status, HOI, and receipt of adjuvant therapy.

Conclusion: Surgery for recurrent RPS remains a viable option, particularly in the early stages of recurrence. Inadequate initial resections lead to significantly higher recurrence rates and worse survival outcomes. The study underscores the importance of initial treatment at specialized centers, multidisciplinary management, and personalized surgical strategies in improving survival rates in Rec RPS