A cell kinetic study on medulloblastomas.

The cell kinetics of medulloblastoma were studied to define characteristic proliferation for comparison with other neuroectodermal tumors. Four patients with cerebellar medulloblastoma received 3H-thymidine intravenously 1 to 2 days before surgery. Biopsy specimens from each tumor were processed for autoradiography. The respective average labeling indices were 14.4%, 14.1%, and 11.2% in the three mid-cerebellar medulloblastomas and 8.0% in the cerebellar hemispheric medulloblastoma. The mean survival time with various treatments including radiation therapy before or after the study in these four patients was 6 years (range, 3-9 years). In contrast, patients with malignant gliomas that had a labeling index greater than 5% died within 1 year. This difference in survival was attributed to the greater sensitivity of medulloblastoma to radiation therapy.