Brain metastases in malignant teratoma: a review of four years' experience and an assessment of the role of tumour markers.

Between 1973 and 1977, 247 patients with malignant teratoma have been treated in two units in London. Seventeen have developed brain metastases, an overall incidence of 6.2%. The median survival from diagnosis of cerebral metastases is 6 weeks and all patients except one have died. The survivor is disease-free 12 months after completing treatment, which included extensive use of chemotherapy, surgery and radiotherapy. Serum gonadotrophin (HCG) and alpha-foetoprotein (AFP) estimations have been performed in 264 patients as a means of monitoring the effects of therapy. In 42 patients (37 of whom had Stage IV disease) the peak HCG level was greater than 10(4) iu/l, and the incidence of brain metastases in this group was 26%, significantly higher than in the group with HCG levels below 10(4) iu/l, for which the incidence of cerebral deposits was 1.8% (P less than 0.0001). No significant correlation was seen between peak AFP levels and the incidence of brain metastasis. With the aim of improving results by earlier diagnosis, cerebrospinal fluid (CSF) specimens have been examined for HCG and AFP levels in 56 subjects, 9 of whom had brain metastases. A serum: CSF HCG ratio less than 40 is an accurate indication of the presence of brain metastases, and may have considerable predictive value. However, false-negative serum: CSF HCG rations (greater than 40) frequently occur in patients with proven brain deposits. Estimation of AFP in spinal fluid has not contributed to the early diagnosis of brain metastases in malignant teratoma.