Does up-front definitive surgical resection with delayed chemotherapy in patients with stage IV rectal cancer compromise overall survival?

Abstract

586 Background: Definitive resection of the primary is frequently part of the management of patients (pts) with stage IV rectal cancer with good performance status and low volume of systemic metastases. It is unclear whether delaying systemic therapy for up front surgical management of the primary compromises overall survival (OS). Methods: Pts with metastatic rectal adenocarcinoma who received definitive surgical resection between 1998-2011 were identified in an IRB approved registry. The sequencing of CT and surgery, and the use of perioperative radiation therapy (RT), was at the discretion of treating physicians. Preoperative chemotherapy (Pre-CT) regimens included 5-fluorouracil (5-FU) +/- leukovorin (LV), capecitabine, 5-FU/LV/oxaliplatin +/- avastin, or 5-FU/LV/irinocetan. RT dose was typically 50.4 Gy. OS was measured from the date of diagnosis. Baseline variables were compared using the Chi-square and unpaired t-tests. OS was calculated using the Kaplan Meier method. Univariate (UVA) and multivariate analysis (MVA) were performed using Cox proportional hazards regression to identify variables associated with OS. Results: In this study of 115 pts, 75 (65%) were treated with pre-CT, while 40 (35%) were treated with up front surgery. Of the pts who received surgery up front, 3 (8%) received RT and of the pts who received pre-CT, 62 (83%) received RT. The cohort was predominantly male (70%) with a median age of 57, median KPS of 80, and median follow-up of 24.1 months. 94% of pts had T3/T4 tumors, 80% had N+ disease, and 33% had poorly differentiated tumors. Liver directed therapy (LDT) was performed in 61% of pts. There was no significant difference in OS (32.3 vs. 32 months; p = 0.24) between pts treated with pre-CT and those who received surgery up front, respectively. UVA demonstrated that pre-CT was not associated with OS (HR 1.26; p = 0.544). MVA demonstrated that pts with poorly differentiated tumors (HR 2.04; p = 0.007) and those that did not undergo LDT (HR 2.45; p = 0.001) had inferior survival. Conclusions: Delaying systemic chemotherapy in order to achieve local control with surgical resection up front does not appear to impact OS in pts with stage IV rectal cancer.