A re-evaluation of carcinoembryonic antigen (CEA) as a serum marker for breast cancer: a prospective longitudinal study.

Purpose: Carcinoembryonic antigen (CEA) is still a widely used test for monitoring breast cancer, although recent reports discourage its routine use because of low sensitivity. This is a prospective study evaluating the efficacy of CEA and CA 15.3 in monitoring breast cancer.

Experimental Design: Serum CEA and CA 15.3 were measured in 2191 patients with either benign (n = 738) or malignant (n = 1453) breast diseases. Five hundred and forty-nine patients were monitored during postsurgical follow-up for either a minimum of 5 years or until time of recurrence. Fifty-three patients with metastases were also monitored during chemotherapy.

Results: Elevated CEA and CA 15.3 levels were found in 16.7% and 33.0% of patients, respectively. CEA sensitivity rose to 41.3% and CA 15.3 sensitivity rose to 80.8% in metastatic patients. The adjunct of CEA increased the CA 15.3 sensitivity by 6% in the overall population and by only 2.1% for patients with metastases. During postsurgical follow-up, CEA was elevated in 38.0% and CA 15.3 in 70.2% of patients with recurrence. The combination of CEA and CA 15.3 increased the overall sensitivity by only 1.4%. Longitudinal monitoring of 53 metastatic patients undergoing chemotherapy demonstrated that, when positive, both CEA and CA 15.3 paralleled response to treatment, although CA 15.3 was a significantly more powerful marker for determining response to treatment. The cost effectiveness ratio of CEA was clearly less favorable than that of CA 15.3.

Conclusions: CEA monitoring should be considered an expensive and inefficient method of follow-up evaluation for breast cancer patients, and it provides no additional value when used in combination with CA 15.3.