Radioimmunoassay of hCG as an early diagnosis of cerebral metastases in choriocarcinoma patients.

To determine the early cerebral involvement of choriocarcinoma, the following studies were employed. By comparing hCG titers in measurements of serum and cerebrospinal fluid (CSF) hCG-beta through radioimmunoassay (RIA), serum/CSF ratios of titers were calculated in patients with normal pregnancies and in those with trophoblastic neoplasia. In normal pregnancies, the mean ratio of serum/CSF hCG was more than 45.5 +/- 6.0 (mean +/- SEM):1. In neoplasia without metastases to the brain, the ratio was more than 41.0:1. However, 2 patients with cerebral choriocarcinoma showed low ratios of 23.0:1 and 20.9:1, respectively. This suggests that determination of the beta-hCG concentration ratio of serum to CSF using RIA might give a more reliable evaluation for the early detection of choriocarcinoma metastasized to the brain.