Intrathecal cytostatic therapy of meningeal carcinomatosis. Autoradiographic investigations of the CSF cells.

Autoradiographic investigations with 3H-thymidine were performed on cerebrospinal fluid (CSF) cells from a case of meningeal carcinomatosis following carcinoma of the breast. The cells were found to be anaplastic histologically. Within a period of 12 days 3 X 25 mg methotrexate were injected into the subarachnoid space by lumbar (2 X) or cisternal (1 X) puncture. The CSF cells were reduced from 283/3 to 19/3, while the proportion of tumour cells fell from 90 to 2%. The labelling index before onset of therapy was 33%; it increased to 70% after the first intrathecal administration of cytostatic and finally fell to 23%. The mitotic index, which was generally less reliable, behaved in a parallel way; the initial value of 1.5% increased to 3% and then declined to values less than 0.5%. Despite detailed histological investigation, carcinomatous cells could not be found anywhere on the surfaces of the central nervous system or meninges. Clinically, the patient had never shown significant neuropathological or psychopathological findings. However, the headache which had been very severe during the meningeal carcinomatosis vanished completely after the second application of methotrexate.