Preoperative elevation of carcinoembryonic antigen predicts poor tumor response and frequent distant recurrence for patients with rectal cancer who receive preoperative chemoradiotherapy and total mesorectal excision: a multi-institutional analysis in an Asian population.

Purpose: This study was conducted to evaluate the significance of carcinoembryonic antigen (CEA) level as a predictor for tumor response to chemoradiotherapy (CRT) and a prognosticator for survival in Asian patients with advanced rectal cancer.

Materials And Methods: We enrolled 345 patients with primary rectal cancer who had undergone preoperative CRT and total mesorectal excision. We analyzed clinicopathological factors that could be associated with pathologically complete response (ypCR) and disease-free survival (DFS).

Results: A cutoff level of 5 ng/mL (p = 0.002) for CEA was found to be significant for prediction of ypCR. Increased CEA level (p = 0.025) was a significant negative predictor of ypCR after CRT in patients with rectal cancer. The 5-year DFS rate was significantly higher in the CEA ≤5-ng/mL group than in the CEA >5-ng/mL group (73.2 vs. 60.9 %, p = 0.002). This is mainly due to the higher chance of distant recurrence (p = 0.013), not locoregional recurrence (p = 0.732), in the CEA >5-ng/mL group.

Conclusions: Elevated CEA (>5 ng/mL) is a negative predictor of ypCR and has a negative impact on DFS in Asian rectal cancer patients who underwent preoperative CRT and surgery due to an increased chance of distant recurrences.