The miniscule benefit of serial carcinoembryonic antigen monitoring after effective curative treatment for primary colorectal cancer.

BACKGROUND: Serial carcinoembryonic antigen (CEA) levels have been recommended to detect asymptomatic recurrent colorectal cancer and to facilitate curative additional therapy. This study was designed to investigate the outcome of additional treatment for recurrent cancer in patients undergoing primary colorectal cancer treatment in a specialty center and subsequent relapsing with an elevation in serum CEA. STUDY
DESIGN: Patients treated for their primary cancers at our institution whose followup included CEA monitoring and whose cancers subsequently recurred, were analyzed from a prospective database of almost 1,900 patients. CEA levels of > or = 5 ng/mL were considered elevated for purposes of treatment results. One hundred sixty-three patients were suitable for analysis. Median followup before and after recurrence was 14 months and 16 months, respectively.
RESULTS: Fifty patients were able to undergo complete resection of their recurrence, and 26 of these patients are without evidence of recurrence at last followup. Two-thirds of recurrences were associated with an elevation of CEA; this elevation at recurrence was associated with decreased survival (p < 0.05, Kaplan Meier). Of the 109 patients with an elevation of CEA at recurrence, complete re-resection was accomplished in 26 patients. Of these, half remain cancer free. Of those with a normal CEA at recurrence, complete re-resection was feasible in 24 patients.
CONCLUSIONS: Only 17% of patients with recurrent colorectal cancer undergoing potentially curative reresection have an elevated CEA. If we use the denominator of our patient population using an estimated relapse rate of 25-50%, the overall likelihood of CEA-directed curative re-resection confirms early estimates of less than a 5% survival advantage.