The value of serial plasma levels of carcinoembryonic antigen and gross cyst disease fluid protein in patients with breast carcinoma and osseous metastases.

Serial plasma levels of the glucoprotein tumor markers carcinoembryonic antigen (CEA) and gross cyst disease fluid protein (GCDFP) were evaluated in 83 patients undergoing treatment for predominant osseous metastases from breast carcinoma. Abnormal plasma levels of CEA (greater than 10 ng/ml) and/or GCDFP (greater than 150 ng/ml) were observed in 53 (63.8%) subjects. Fifty-six courses of hormonal and chemical therapy were evaluated. Clinical response to therapy correlated positively with alterations in serial plasma levels of CEA and/or GCDFP. Increasing plasma levels of tumor markers were associated with clinical disease progression whereas decreasing plasma levels were associated with and generally preceded clinical disease remission. Of patients with metastatic carcinoma of the breast, responses to therapy are most difficult to evaluate in those with bone metastases. Serial determinations of plasma levels of CEA and/or GCDFP provide an objective indication of disease progression and regression and appear to be useful with skeletal x-rays and bone scans in evaluating patients with carcinoma of the breast.