Retroperitoneal soft-tissue sarcomas: Radiotherapy experience from a tertiary cancer center and review of current evidence.

Abstract

Surgery remains to be the main therapeutic approach for retroperitoneal sarcomas (RPS) although evidence supports that complementary radiotherapy increases local-control and survival. We present a multidisciplinary management and experience of a tertiary cancer center in the treatment of RPS and analyze current evidence of radiotherapy efficacy. We retrospectively reviewed 19 patients with primary or relapsed RPS treated between November 2009 and October 2018. Multidisciplinary approach comprised complete resection in 15 patients (79%) achieving resection R0 in 11 patients (58%), R1 in 4 patients (21%) and R2 in 2 patients (10%). Seven patients (37%) underwent a preoperative radiation (PRORT), 10 patients (53%), post-operative radiation (PORT) and 2 patients (10%), received radiotherapy exclusively. Ten patients (53%) received adjuvant chemotherapy. With a median follow-up of 24 months (2-114 months), actuarial rates of loco-regional relapse free survival (LRFS) at 1, 2 and 3 years were 77%, 77% and 67%, respectively. Actuarial rates of distant-metastases-free survival (DMFS), disease-free survival (DFS) and overall survival (OS) at 1, 2 and 3 years were 100%, 100% and 80% for DMFS; 94%, 77% and 67% for DFS and 100%, 91% and 91% for OS, respectively. Only surgical margins (negative vs. positive) showed significance for 3y-LRFS: 100% vs. 34.3%, p=0.018. Treatment tolerance was acceptable with no acute or late toxicity higher than grade 2. Complementary radiotherapy appears to be useful and well tolerated for the multidisciplinary management of RPS. Presence of positive surgical margins seems to be the most relevant prognostic factor through the follow-up.