Downstaging after preoperative chemoradiation as a prognostic marker for recurrence after curative surgery in locally advanced rectal cancer.

Abstract

e14650 Background: 5-fluorouracil (5-FU) based preoperative concurrent chemoradiation (CCRT) with surgery is the standard treatment for resectable rectal cancer. Chemotherapy after surgery improves local control, but there are some debates for the role in 5-FU based adjuvant chemotherapy. This study was aimed to analyze the tumor recurrence pattern in locally advanced rectal cancer, and the relationship between clinicopathologic factors with tumor recurrence. Methods: One hundred forty-nine patients with locally advanced rectal cancer, receiving preoperative 5-FU based CCRT (radiation dose: 5040 cGy) with total mesorectal excision (TME), followed by adjuvant 5-FU based chemotherapy were enrolled. Sex ratio was 95:54. Median age was 61 (range 37~83). Medical records were reviewed retrospectively. Clinicopathologic factors, oncologic outcomes (tumor recurrence, disease free survival (DFS)) were assessed. Results: Median follow-up duration was 25.3 months (range 5.2~66.2). Median DFS was 19.3 months (range 0~63.4). Thirty-five (23%) patients showed recurrence after surgery. Among tumor recurrence, 86% of patients were presented with distant metastases. Absence of T or N downstaging after 5-FU CCRT was significantly correlated with tumor recurrence (P=0.032 and P=0.011 by Fisher’s exact test, respectively) and longer DFS (P=0.003 and P<.001 by Kaplan-Meier survival curve, respectively). Lymphatic invasion, neural invasion after 5-FU CCRT showed correlation with recurrence (HR=6.37, 95% CI; 2.74-14.84, P<.001; HR=4.9, 95% CI; 1.85-12.97, P=0.002, respectively). In contrast, vascular invasion was not associated with tumor relapse after 5-FU CCRT followed by surgery. Conclusions: The absence of T or N downstaging, the presence of lymphatic or perineural invasion in pathology was associated with tumor recurrence. In spite of 5-FU based adjuvant chemotherapy, distant metastases were more prevalent. In patients with the possibility of distant metastases, more aggressive adjuvant chemotherapy-including platinum agents-should be considered.