The Role of Carcinoembryonic Antigen After Neoadjuvant Chemoradiotherapy in Patients With Rectal Cancer

Abstract

The purpose of this study was to evaluate the role of CEA after neoadjuvant chemoradiotherapy in patients with rectal cancer. This study involved 109 patients with rectal cancer who were treated with preoperative chemoradiotherapy and curative resection. Preoperative serum CEA levels were measured twice, before chemoradiotherapy administration and 4 weeks after chemoradiotherapy. Surgery was performed 6 to 9 weeks after neoadjuvant chemoradiotherapy. The 3-year disease-free survival rate was 85.0%. On univariate analysis, prechemoradiotherapy CEA level, postchemoradiotherapy CEA level, tumor regression grade, ypT, ypN, circumferential resection margin, lymphatic invasion, venous invasion, and perineural invasion were associated with disease-free survival. Based on univariate analysis (group 1: prechemoradiotherapy CEA ≤ 3.5; group 2: prechemoradiotherapy CEA > 3.5, postchemoradiotherapy CEA ≤ 2.7; group 3: prechemoradiotherapy CEA >3.5, postchemoradiotherapy CEA > 2.7), we categorized patients into 3 groups according to their pre- and postchemoradiotherapy CEA levels (ng/mL). The 3-year disease-free survival rate was significantly better in groups 1 and 2 (94.7% and 88.0%) than in group 3 (52.6%, P < .001). On multivariate analysis, tumor regression grade (P = .036), ypN (P = .036), and CEA groups (P = .022) were identified as independent prognostic factors for disease-free survival. Furthermore, postchemoradiotherapy CEA ≤ 2.7 ng/mL was an independent predictor of good tumor regression (P = .001), ypT0 to 2 (P = .002), and ypN0 (P = .001). Combined pre- and postchemoradiotherapy CEA levels could be useful as a prognostic factor for disease-free survival in patients with rectal cancer who undergo treatment with neoadjuvant chemoradiotherapy and curative resection. Postchemoradiotherapy CEA may be helpful in a selection of patients who want more conservative surgery after chemoradiotherapy.