Elevated CEA levels and low distance of the tumor from the anal verge are predictors of incomplete response to chemoradiation in patients with rectal cancer.

ABSTRACT

BACKGROUND: The objective of this study was to evaluate pretreatment clinical parameters as predictive factors for complete pathological response after long-term chemoradiotherapy (RCT) for rectal cancer. Tumor downstaging after RCT for rectal cancer can be obtained in half of cases, whereas a complete pathological response (CPR) is reported to range between 15 and 30%. It is not possible to foresee before therapies who will respond. METHODS: Patients with stage II-III rectal cancer that had undergone RCT and rectal resection between January 1995 and October 2010 were considered. Patients were divided in those who achieved a CPR, "CR" group, and those who did not achieve a CPR, "NCR" group. Univariate and multivariate analyses between groups were performed considering the clinical parameters gender, age, ASA score, preoperative hematic CEA, tumor grading; distance of the tumor from the anal verge, maximum tumor diameter, TNM stage, and neoadjuvant treatment details. RESULTS: Among 260 patients, 43 (16.5%) achieved a CPR. The two groups resulted homogeneous for age, sex, pretreatment status, and tumor stage. A CEA <5 ng/dl and distance from anal verge >5 cm were correlated with CPR at multivariate analysis. Patients with both these conditions presented a significantly higher CPR rate (30.6%) as well as improved 5-year survival. CPR was also correlated with improved survival. CONCLUSIONS: Very low tumors with a high serum CEA are very unlikely to reach a CPR. The predictive value of these easily available clinical factors should not be underestimated, and better therapeutic strategies for these tumors are needed.