Objective: To assess the accuracy of cerebrospinal fluid (CSF)/serum ratio of beta-subunit of human chorionic gonadotropin (beta-hCG) in detecting brain metastasis of gestational trophoblastic tumor (GTT).
Study design: The subjects were ten patients with GTT and brain metastases. Spinal puncture and veni-puncture were performed for measurement of beta-hCG titer in CSF and serum to determine the CSF/serum ratio before starting multiagent chemotherapy and/or brain irradiation.
Results: Five patients manifested a CSF/serum beta-hCG ratio > 1/60, and five manifested a ratio < 1/60.
Conclusion: The CSF/serum beta-hCG ratio is not accurate enough to be routinely considered in the workup, management, and/or surveillance of GTT with brain metastases. Hence, it is perhaps not necessary to perform spinal puncture if the only purpose is to determine the CSF/serum ratio.