Improved monitoring of gestational trophoblastic neoplasia using a highly sensitive assay for urinary human chorionic...

A radioimmunoassay for urinary human chorionic gonadotropin (hCG) which used antiserum to the hCG beta carboxy-terminal peptide was employed to detect hCG production in women with gestational trophoblastic disease. The urinary hCG assay was considerably more effective in detecting increased hCG production, and, hence, persistent tumor burden, than the commonly used serum hCG beta subunit radioimmunoassay. In two women treated for choriocarcinoma, urinary hCG levels remained distinctly elevated for 2 to 6 weeks, even though the serum hCG level was undetectable; in both cases, the urinary hCG radioimmunoassay reliably predicted the eventual reappearance of hCG in the serum. In six women whose disease remitted, the urinary hCG level declined to the normal range during chemotherapy, and remained there afterward. In eight patients who had been in remission for periods of from 1 to 14 years, urinary hCG levels were in the normal range. We conclude that this highly sensitive and reliable method for the detection of hCG production improves the ability to diagnose persistent trophoblastic disease.