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

PURPOSE: The purpose of this study was to evaluate the role of CEA after neoadjuvant chemoradiotherapy in patients with rectal cancer. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.