Prognostic significance of response to preoperative radiotherapy, lymph node metastasis, and CEA level in patients undergoing total mesorectal excision of rectal cancer.

PURPOSE: The aim of this study was to investigate the prognostic significance of the response of primary rectal lesions to preoperative radiotherapy, pathological nodal status, and carcinoembryonic antigen (CEA) levels before and after radiotherapy in rectal cancer patients treated with a total mesorectal excision.
METHODS: We investigated the prognostic significance of the clinical and pathological factors in 97 patients treated with preoperative radiotherapy (50-50.4 Gy over 5-6 weeks) followed by curative resections.
RESULTS: A high CEA level (>5 ng/mL) after radiotherapy (hazard ratio, 2.849; 95% confidence interval, 1.061-7.651; p = 0.0377) and pathological lymph node metastasis (hazard ratio, 0.350; 95% confidence interval, 0.154-0.797; p = 0.0124) were independently associated with postoperative recurrence. Although the CEA level before radiotherapy was associated with disease-free survival in a univariate analysis, it lost its statistical significance in a multivariate analysis. The response of the primary rectal lesions, evaluated pathologically by T stage and the degree of regression, was not associated with disease-free survival. In patients without lymph node metastasis, the 5-year disease-free survival of those with a high CEA level after radiotherapy was significantly worse than those with low CEA after radiotherapy (61.6% vs. 89.0%, respectively, p = 0.0234).
CONCLUSIONS: Pathological lymph node metastasis and a high CEA level after radiotherapy were independent predictors of a poor outcome in rectal cancer patients treated with preoperative radiotherapy. The CEA level after radiotherapy was capable of discriminating patients with a high risk of recurrence among pathologically node-negative patients.