The value of a sensitive assay of carcino-placental alkaline phosphatase (CPAP) in the follow-up of gynecological cancers.

Using a sensitive enzyme immunoassay, carcinoplacental alkaline phosphatase (CPAP) was determined in sera of 1266 patients with gyneocological cancers. All these patients were referred after initial surgical treatment elsewhere. There were 95 patients with evidence of disease at the time of the study and 1171 without evidence of disease. Of the 95 patients with active disease, 47 were treated for ovarian carcinoma, 36 for carcinoma of the cervix and 12 for endometrial carcinoma. Raised levels of CPAP were seen in 40% of patients with ovarian carcinoma, in 22% with carcinoma of the cervix and in 41% in the small group with endometrial carcinoma. In patients without evidence of disease, raised levels of CPAP were seen in 12% of patients with carcinoma of the cervix, in 6% of endometrial carcinoma and only in 2% of patients with carcinoma of the ovary. Therefore it was considered that in the latter group CPAP studies would prove of some value. In the group of patients with carcinoma of the ovary and evidence of disease, raised levels of CPAP were seen almost exclusively in patients with epithelial tumors. It is considered that CPAP may be of value as a tumor marker in this group of patients. When compared with CEA, CPAP tends to give fewer false positives and correlates better with the presence of disease.