Background: Tumor marker-producing germ cell tumors of the central nervous system are malignant and require radiation and/or chemotherapy. Although serum beta-human chorionic gonadotropin (hCG) has been used to monitor the course of treatment, the levels of beta-hCG in the cerebrospinal fluid (CSF) have not been measured routinely in the clinic. To determine whether they can be used to evaluate parameters of tumor status, such as progression or response to therapy, levels of beta-hCG in the serum and CSF of patients with germ cell tumors were studied.
Methods: Fifty-four paired samples of CSF and serum were taken from seven patients with germ cell tumor and their beta-hCG levels were measured. Beta-hCG was negative in both serum and CSF in 11 instances and the levels in the other 43 paired samples were analyzed for any correlation or relationship to therapy. They were also compared with the clinical courses.
Results: The mean CSF beta-hCG level was 11.5 mIU/ml, which was significantly higher than the level in serum (3.5, p = 0.002). In all the paired samples except for one time point, the level in CSF was higher than that in serum. Out of 43 instances where the beta-hCG level in CSF was elevated, the level in serum was elevated in only 16 (37.2%). Among cases of recurrent malignant germ cell tumor, there were nine instances of recurrence or progression despite therapy. In all five instances where beta-hCG CSF levels were measured, the levels were elevated prior to any increase or detectability of the serum values.
Conclusion: It seems likely that the level of beta-hCG in CSF is a good marker for monitoring tumor recurrence or evaluation of treatment results.