Carcinoembryonic antigen (CEA) in ovarian cancer: factors influencing its incidence and changes which occur in response to cytotoxic drugs.

We report the serum levels of carcinoembryonic antigen (CEA) in 109 patients with ovarian cancer. Histology, degree of differentiation, and clinical stage influenced the incidence of positive CEA. Although CEA was significantly raised in patients with a variety of tumours, the highest incidence (77 per cent) was found in those with serious cystadenocarcinoma. Nearly all (94 per cent) of the poorly differentiated tumours were associated with a positive CEA result. Serial CEA levels provided a useful guide to management during cytotoxic chemotherapy, rapidly falling levels indicating a favourable tumour response which was reflected clinically. However, only two-thirds of tumours were associated with detectable CEA levels in serum, day-to-day variations in individual serum levels occurred, and CEA levels tended to fall paradoxically during terminal illness. The significance of persistently low levels in the apparent absence of disease was uncertain.