Medulloblastoma at the joint center for radiation therapy between 1968 and 1984.The influence of radiation dose on the patterns of failure and survival

Abstract

In order to assess the efficacy of high-dose irradiation to the posterior fossa and low-dose irradiation to the spinal axis, we reviewed the results of 60 patients with biopsy-proven medulloblastoma treated at the Joint Center for Radiation Therapy (JCRT) between 1968 and 1984. The 5- and 10-year actuarial survival rates for all patients were 68% and 44%, respectively. The median time to recurrence was 19 months. Extent of surgery, age, and radiation dose to the posterior fossa all were of prognostic value. Complete or subtotal gross resection appeared to be a favorable prognostic indicator compared with biopsy only (P less than 0.05), with a 69% versus 40% actuarial survival rate at 5 years, respectively. Infants 2 years of age or less had a diminished 5-year actuarial survival rate of 48% (P less than 0.05) compared with older age groups. The posterior fossa was the predominant site of recurrence and accounted for 78% of all failures. Local control in the posterior fossa was dose dependent. Seventy-nine percent of the tumors that received 5000 cGy or greater were controlled versus only 33% of the tumors that received less than 5000 cGy (P less than 0.02). There were no supratentorial failures, and there was only one isolated spinal cord failure. There were no solitary spinal failures in 24 patients who received a median dose of only 2400 cGy to the spinal axis. We concluded that low-dose irradiation to the spine and whole brain may be indicated with maintenance of a posterior fossa dose of greater than 5000 cGy.

Medulloblastoma: tumor biological and clinical perspectives

“…The need to irradiate the entire neuraxis is clear, as well as the failure of chemotherapy to compensate for volume reductions [67]. A dose response for the primary tumor highlighting the need for greater than 50 Gy to the posterior fossa has been noted in several series [68,69]. The need for a specific dose of [35][36][37][38][39][40][41][42][43][44][45] Gy to the neuraxis was, until recently, less clear.…”

The prognostic significance of postoperative residual contrast enhancement on CT scan in pediatric patients with medulloblastoma

“…During the last two decades the combination of surgical resection, craniospinal axis irradiation and perhaps adjuvant chemotherapy has significantly increased the survival rate of children with medulloblastoma, with recent studies indicating 5-year survival rates of approximately 60% [1][2][3][4][5][6][7][8][9]. Nonetheless, a proportion of patients continues to have tumor recurrence.…”

Surgical management of medulloblastoma

“…The presence of a desmoplastic component within a medulloblastoma has been related by some authors to a somewhat improved survival [58][59][60]. Others have associated this histological variant with a worse prognosis [10,61], and its significance remains uncertain.…”