HYPERFRACTIONATED CRANIOSPINAL RADIATION IN MEDULLOBLASTOMA

From 1986 to 1991, 13 patients at Northwestern Memorial Hospital were entered onto a pilot study designed to test the feasibility of treatin g children with medulloblastoma (11 patients) or primitive neuroectode rmal tumors of the cerebral hemispheres (2 patients) with hyperfractio nated craniospinal radiotherapy (HFxRT). Follow-up times ranged from 1 0 to 96 months with a median of 53 months. The patients were prospecti vely divided among three treatment arms depending on prior treatment h istory, if any, and degree of surgical resection. The 3 patients in gr oup I had undergone gross total resection of the primary site, receivi ng 64.8 Gy to the primary site and 31.2 Gy directed to the craniospina l axis (CSA). Of these 3 patients, patient 1 had residual disease in t he thoracic spine at T-10. The 8 patients in group II, who had gross r esidual disease remaining at the primary site, received 72 Gy to the p rimary site and 34 Gy to the CSA. Five of these eight patients in grou p II also received 8-in-1 chemotherapy. The 2 patients in group III ha d already failed chemotherapy and were then treated with 60 Gy to the primary site and 26 Gy to the CSA. Of the 11 patients in groups I and II, 7 of the 11 (64%) have never recurred. Two of the three group-I pa tients have not recurred, and 5 of the 7 group-II patients have not re curred. In addition, patient 7 (group II) remains alive after salvage with bone marrow transplant, following a local failure bordering the t entorium. Unfortunately, neither of the group-III patients could be sa lvaged with HFxRT. Acute/subacute toxicities included 7 cases of exter nal auditory canal or skin desquamation, 2 cases of postradiation somn olence, and 1 case each of poor wound healing and neutropenia. Chronic toxicities included hypothyroidism in 2 patients and growth problems in 2 patients. Neuropsychologic complications affected only the 3 youn gest patients in the study. Three patients developed neurologic sequel ae attributed to radiation, including 1 with progressive urinary incon tinence, 1 who developed a transient ischemic attack, and 1 who became progressively ataxic. Our research, although based on a small number of patients, suggests that hyperfractionated radiation therapy to cran iospinal access is feasible and that the survival results are favorabl e. This treatment strategy should be further explored in a phase-III r andomized trial.