Prognostic Significance of Serum Carcinoembryonic Antigen Normalization on Survival in Rectal Cancer Treated with Preoperative Chemoradiation

PURPOSE: The purpose of this retrospective study was to identify factors predictive of survival in rectal cancer patients who received surgery with curative intent after preoperative chemoradiotherapy (CRT). MATERIALS AND METHODS: Between July 1996 and June 2010, 104 patients underwent surgery for rectal cancer after preoperative CRT. The median dose of radiotherapy was 50.4 Gy (range, 43.2 to 54.4 Gy) for 6 weeks. Chemotherapy was a bolus injection of 5-fluorouracil and leucovorin for the first and last week of radiotherapy (n=84, 77.1%) or capecitabine administered daily during radiotherapy (n=17, 16.3%). Low anterior resection (n=86, 82.7%) or abdominoperineal resection (n=18, 17.3%) was performed at a median 47 days from the end of radiotherapy, and four cycles of adjuvant chemotherapy was administered. The serum carcinoembryonic antigen (CEA) level was checked at initial diagnosis and just before surgery. RESULTS: After a median follow-up of 48 months (range, 9 to 174 months), 5-year disease free survival (DFS) was 74.5% and 5-year overall survival (OS) was 86.4%. Down staging of T diagnoses occurred in 32 patients (30.8%) and of N diagnoses in 40 patients (38.5%). The CEA change from initial diagnosis to pre-surgery (high-high vs. high-normal vs. normal-normal) was a statistically significant prognostic factor for DFS (p=0.012), OS (p=0.002), and distant metastasis free survival (p=0.018) in a multivariate analysis. CONCLUSION: Patients who achieve normal CEA level by the time of surgery have a more favorable outcome than those who retain a high CEA level after preoperative CRT. The normalization of CEA levels can provide important information about the prognosis in rectal cancer treatment.