Do all patients with primary retroperitoneal sarcoma benefit from resection?

Abstract

e23549 Background: We aimed to determine the impact of early recurrence on the prognosis of patients who have undergone resection of primary retroperitoneal sarcoma (RPS) and to discover which preoperative patient/tumor features predict early recurrence. Methods: Consecutive patients with primary non-metastatic RPS who were managed at two high volume RPS referral centers between 03/2012 and 10/2019 were identified from prospectively maintained institutional databases. The primary study endpoint was Overall Survival (OS), defined as the time from diagnosis to death from any cause, estimated by the KM method. Patients were grouped by Disease-Free Interval following resection (DFI = 0-6, 7-12, 13-18, 19-24, > 24 mos). Univariate and multivariable analyses (UVA, MVA) were performed. The Sarculator risk calculator and the Inflammatory Biomarkers Prognostic Index (IBPI) were assessed as potential predictors of early recurrence, defined as DFI 0-6 mos. Results: 651 patients (median age = 62.7yrs, IQR = 51.9-71.3; F:M = 301:350) met inclusion criteria and form the study cohort. Median follow-up time was 75.9 mos (IQR 58.6-99.5). 566 of the 651 (87%) patients underwent resection of their primary RPS, while 85 (13%) did not, most commonly due to suboptimal PS. Of the 566 patients who underwent resection, 259 (46%) had developed a recurrence by the time of last follow-up, while 307 patients (54%) had not recurred. In the 259 patients whose tumor recurred, 49 (19%) recurred within 6 mos of primary RPS resection, 42 (16%) between 7 and 12 mos, 35 (14%) between 13 and 18 mos, 31 (12%) between 19 and 24 mos, and 102 (39%) after 24 mos. Patients who developed recurrence within 6 mos of resection had similar OS from the time of diagnosis to the 85 patients who did not have a resection (1-year estimates: 77.3% [95% CI: 66.4-90.1] vs 65.7% [56.1-76.8], respectively; 2-year estimates: 51.6% [39.1-68.0] vs 42.7% [33.1-55.1], p = 0.32), while patients who relapsed more than 6 mos after resection had longer OS than either of these groups (p < 0.001). Upon MVA, the HR for death in patients who recurred within 6 mos vs. that of patients who were not resected was 0.96 (95% CI: 0.60-1.53). No standard clinico-pathologic variable available preoperatively could be identified that predicted recurrence within 6 mos of primary resection. Neither composite score (Sarculator, IBPI) was able to reliably predict recurrence within 6 mos. Conclusions: DFI from primary RPS resection to first recurrence was less than 6 mos in ≈20% of patients. DFI directly correlated with OS from time of diagnosis. Patients who recurred within 6 mos of resection had an equivalent OS to patients who didn’t undergo resection, raising the question of whether resection was of any benefit. Current efforts focus on discovery of genomic characteristics that reflect adverse biology/host response and are discoverable preoperatively, in order to improve patient selection for surgery and for neoadjuvant therapy.