Postoperative borderline elevated CEA predicts for earlier relapse in patients with rectal cancer receiving adjuvant postoperative therapy.

PURPOSE

The purpose of this study was to determine the impact of a borderline elevated postoperative carcinoembryonic antigen (CEA) on the duration of disease-free survival in patients with rectal cancer treated with postoperative adjuvant radiotherapy and chemotherapy.

PATIENTS AND METHODS

A retrospective review was undertaken of 145 patients undergoing curative surgery for rectal adenocarcinoma (American Joint Committee on Cancer stages II and III) and treated with postoperative radiotherapy and chemotherapy from January 1994 to February 1997. Patients with known metastatic disease, with gross residual disease after surgery, or without an available postoperative CEA level before adjuvant therapy were not included. All patients were monitored for a minimum of 1 year or until death. The rates of relapse, disease-free survival and overall survival were estimated according to the Kaplan-Meier method. Univariate analyses for the endpoint time to relapse was carried out for the following potential prognostic factors: age, gender, American Joint Committee on Cancer stage, number of lymph nodes, perineural invasion, capillary-like space invasion, margin status, and postoperative CEA level (< or = 4.0 microg/L vs > 4.0 microg/L). A mulitvariate regression analyses was conducted with the Cox proportional hazards model.

RESULTS

With a median follow-up of 45 months, the disease-free and overall survival rates at 2 years were 78% and 90% respectively. Eight patients were identified who expressed an elevated postoperative CEA (4.1-10.2 microg/L). Two patients had T3N0 tumors; one tumor was T4N0, four tumors were T3N1, and one was T4N1. The median time to first relapse in these eight patients was 26 months, compared with 69 months for the 137 patients with a postoperative CEA in the normal range (0-4.0 microg/L), (log-rank Chi-squared test = 4.92). As determined by a proportional hazards model, an elevated CEA remained an independent predictor (along with number of positive nodes) for early relapse.

DISCUSSION

Postoperative CEA in patients undergoing curative surgery for rectal cancer provides additional prognostic information in those patients embarking on adjuvant postoperative therapy. An elevated CEA predicts for early relapse and may help define a high-risk subset of patients in whom more aggressive adjuvant therapies should be considered.