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.