Improvements in the radiotherapy of medulloblastoma, 1946–1975

Abstract

The prognosis in medulloblastoma has often been reported to be gloomy, and five-year survival rates of approximately 25% are often reported. In recent years, however, some centers have published results that indicate a possible cure rate of 60% or even more. During the years 1946-1975, 50 children received radiotherapy for medulloblastoma at the University Hospital, Lund, Sweden. During this period the target volume had been defined in three different ways, whereas the target-absorbed dose had not differed. When only the demonstrated tumor was treated, the ten-year survival rate was 5%. If the spinal subdural space also was included, it rose to 25%, and when the whole subdural space was treated in addition to the demonstrated tumor, the projected ten-year survival rate was 53%. It is apparent that the target volume in the radiotherapy of medulloblastoma should include not only the demonstrated tumor but also the whole subdural space from the tip of the frontal lobes down to and including the second sacral segment. The size of the target-absorbed dose to be aimed at is not settled, but should consider not only the cure rate but also the performance status of the survivors. It seems from the present series that an absorbed dose of 45 Gy in not more than 30 fractions over six weeks to the demonstrated tumor and 30 Gy in 20 fractions over four weeks to the subdural space resulted in a fair frequency of tumor healing and minimal side effects. The delivery of this complicated treatment demands a high degree of precision in the technique. In this material the performance status of the children was not affected by the radiation treatment.

PI3K pathway regulates survival of cancer stem cells residing in the perivascular niche following radiation in medulloblastoma in vivo

“…Standard therapy for medulloblastoma patients includes surgery and irradiation followed by chemotherapy, leading to 50%-80% 5-yr survival. These tumors are radiosensitive; however, long-term side effects of radiation therapy have led to attempts to decrease the amount of craniospinal and local tumor site irradiation, with resultant disease relapse (Landberg et al 1980;Hershatter et al 1986;Deutsch et al 1996). The doses of radiation delivered at the primary site and neuroaxis in children with medulloblastoma have been chosen empirically and not optimized by randomized studies.…”

Preradiation chemotherapy of children and young adults with malignant brain tumors: Results of the german pilot trial HIT'88/'89.

“…Achallenging issue of our pilot trial was the actual delay of the radiation therapy for a median time of 23 weeks. A failure rate of about 30% would have been the consequence of ineffective treatment (23). The overall risk of disease progression during preradiation chemotherapy of the POG trial was 23% in 30 high risk patients with medulloblastoma (24).…”

Advances in Radiation Therapy in Pediatric Neuro-oncology

“…In most cases, the greatest overall survival benefit was achieved with craniospinal irradiation. 14 Highlighting the importance of comprehensive radiation to this region, there are anecdotal studies suggesting that underdosing of the anterior cranial fossa is associated with subfrontal recurrences. 15-16 In parallel, numerous laboratory-based studies demonstrated that medulloblastoma tumor cells are intrinsically radiosensitive.…”