Transient elevation in serum carcinoembryonic antigen while on adjuvant chemotherapy for colon cancer: Is this of prognostic importance?

Abstract

Aims: Serum carcinoembryonic antigen (CEA) is used to detect relapses from colon cancer following initial surgical or adjuvant treatment. There are little data on transient elevations of CEA while receiving chemotherapy in the adjuvant setting. We aimed to review patterns of change in CEA levels while receiving adjuvant chemotherapy and investigate associations between transient rises and patient survival. Methods: A retrospective review of patients in Auckland with a new diagnosis of colon cancer in 2001 or 2005 was performed and CEA values were collected. Three patient groups were defined: no increase in CEA; transient elevation in CEA; and persistent elevation in CEA. Kaplan–Meier methods were used to estimate 5-year survival; Cox regression and log-rank P-values were used to compare survival. Results: Sixty-one patients with stage II or III disease who had received adjuvant chemotherapy had sufficient CEA data to be included in the analysis. Patients were followed up for a minimum of 7.4 years (or death). The 5-year overall survival was higher in the transient elevation in CEA group 95.0% and the no increase in CEA group 85.2% compared with the persistent elevation in CEA group 42.9%. There was no statistically significant difference in overall survival between the transient elevation group and the no increase group (P = 0.2). Conclusions: The group with a transient elevation in CEA during adjuvant chemotherapy did not have a poorer prognosis compared with the group that had no increase in CEA. This will be further examined in a population-based New Zealand-wide study of colorectal cancer diagnosis, treatment and outcome.