Can serum dynamics of carcinoembryonic antigen level during neoadjuvant chemoradiotherapy in rectal cancer predict tumor response and recurrence? A multi-institutional retrospective study.

Abstract

We evaluate whether the change of carcinoembryonic antigen (CEA) level before and after preoperative chemoradiotherapy (CRT) in rectal cancer affects tumor response and recurrence or not. We retrospectively analyzed 1447 rectal cancer patients who underwent preoperative CRT followed by curative surgery. All patients received preoperative radiotherapy of 50.4Gy in 28 fractions with 5-fluorouracil or capecitabine. Total mesorectal excision was performed 4 to 8weeks after preoperative CRT. CEA levels were checked before and after CRT. Clinical and pathologic factors were analyzed for tumor response and recurrence. Post-CRT CEA level (cutoff value, 2.5ng/mL) was not a significant factor for tumor response on the multivariate analysis (p=0.095). Patients were categorized according to the pre- and post-CRT CEA level (group A: pre-CRT CEA ≤5ng/mL; group B: pre-CRT CEA >5ng/mL and post-CRT CEA ≤2.5ng/mL; group C: pre-CRT CEA >5ng/mL and post-CRT CEA >2.5ng/mL). The relapse-free survival (RFS) at 5years was significantly higher in group A than in groups B and C (82.6 vs. 73.7% vs. 72.2%, p<0.001). The overall survival (OS) at 5years was significantly higher in group A than in groups B and C (90.1 vs. 84.4% vs. 83.4%, p<0.001). However, there is no significant difference for RFS and OS between groups B and C (all, p>0.05). Decline of elevated CEA level (>5ng/mL) during preoperative chemoradiotherapy has no significant effect on tumor response and recurrence in rectal cancer.