Serum carcinoembryonic antigen in the diagnosis and prognosis of women with breast cancer.

Serum carcinoembryonic antigen (CEA) has been measured in 628 patients before and 577 patients after treatment for breast cancer. These came from an unselected sequence of 730 women, subsequently diagnosed as having stage I or II breast cancer, referred to Guy's Hospital over a period of nearly 5 yr. CEA was also measured in serum from 238 ostensibly healthy volunteers and 65 women with benign breast disease. CEA measurements were of no diagnostic value. There were more patients with breast cancer with values in excess of 10 ng/ml measured preoperatively (7%) or after mastectomy (5%) than in controls (3%), but the difference is of marginal significance. High levels of CEA were not consistently associated with pathological stage or histological grade. Mastectomy was not associated with any significant change in the distribution of CEA levels. Patients with stage II disease and pre-operative CEA levels over 10 ng/ml has a faster recurrence rate than those with levels of less than 2.5 ng/ml. High levels were also associated with reduced survival. However, such patients comprised about 5% of women presenting with early breast cancer, so that the use of CEA measurements for prognosis is of limited value.