Clinical significance of pre- to post-chemoradiotherapy s-CEA reduction ratio in rectal cancer patients treated with preoperative chemoradiotherapy and curative resection.

Abstract

To evaluate the clinical significance of a reduction in serum carcinoembryonic antigen (s-CEA) concentration ratio from before to after preoperative chemoradiotherapy (CRT) in terms of recurrence and prognostic factors in rectal cancer patients. We retrospectively evaluated 333 rectal cancer patients who received preoperative CRT followed by surgery with curative intent between January 2000 and December 2006. Patients were divided into three groups: those with pre-CRT s-CEA≤6 ng/mL (group 1), those with pre-CRT s-CEA>6 mg/mL and post-CRT s-CEA≥70% lower than pre-CRT s-CEA (group 2), and those with pre-CRT s-CEA>6 mg/mL and post-CRT s-CEA<70% lower or higher than pre-CRT s-CEA (group 3). The 5-year disease-free survival rate was similar in group 1 (76.0%) and group 2 (66.0%), but significantly lower in group 3 (39.5%) (p<0.001). Multivariate analysis showed that CEA group 3, ypT stage, ypN stage, and type of surgery were independent prognostic factors for disease-free survival. The reduction ratio of pre- to post-CRT s-CEA concentration may be an independent prognostic factor for disease-free survival following preoperative CRT and surgery in rectal cancer patients with initial s-CEA>6 ng/mL.