The role of carcinoembryonic antigen in the postmastectomy follow-up of primary breast cancer and in the prognostic evaluation of disseminated breast cancer.

: Serum levels of carcinoembryonic antigen (CEA) were evaluated in 145 patients with breast cancer. There were 107 patients with "indolent" disease: 8 had previous metastases in complete posttherapeutic remission and were CEA-negative; CEA became positive in 2 of 3 of these cases who subsequently relapsed. The other 99 patients were without clinical evidence of disease after mastectomy. Of these, 82 were disease-free and CEA-negative, 2 relapsed and simultaneously became CEA-positive, 4 had recurrences but remained CEA-negative, 4 became CEA-positive but without clinical signs of metastases, and 7 became CEA positive before the clinical-instrumental diagnosis of metastasis. CEA was positive in 23 of 38 patients (60.5%) with "active" disease. Response to medical therapy occurred in 6.6% of CEA-negative patients compared to 55.0% of CEA-positive patients. Among CEA-positive patients, there was a similar percentage of response to medical therapy in patients with small (50.0%) or large (56.5%) tumor burden. A response to medical therapy was observed in all patients with a disease-free interval equal to or greater than 24 months and CEA-positive.