Chemotherapy-induced carcinoembryonic antigen surge in patients with metastatic colorectal cancer.

OBJECTIVES

To investigate the incidence of carcinoembryonic antigen (CEA) surge in patients with metastatic colorectal cancer (MCRC) and its implications on clinical outcome.

METHODS

A retrospective chart review of patients with MCRC treated with chemotherapy at Roswell Park Cancer Institute from January 2000 to May 2004 was conducted. A CEA surge was defined as an increase of >20% from baseline followed by a >20% drop in one or more subsequent CEA levels compared to baseline. The incidence of CEA surge and its association with clinical outcome was investigated.

RESULTS

Eighty-nine patients were evaluable for CEA surge. A CEA surge was documented in 10 patients. The CEA surge lasted <4 months in all 10 patients and was associated with a clinical benefit. No significant correlation was noted between CEA surge and site of primary tumor, site of metastatic disease, or tumor differentiation.

CONCLUSIONS

CEA surges can be observed in patients receiving chemotherapy for MCRC and are often associated with a clinical benefit. None of the CEA surges satisfied the American Society of Clinical Oncology definition of CEA progression. A rise in CEA after initiation of chemotherapy, unless lasting >4 months, cannot be used as an indicator of progressive disease.