Medulloblastoma in children – the Ottawa experience

Abstract 

A retrospective review of 36 children diagnosed with medulloblastoma in the Ottawa area between 1974 and 1997 was completed (mean age 7.8±4.2 years, range 1.2–15.3 years). Via a suboccipital approach, complete tumor resection was achieved in 75% and subtotal resection (>90%) in 25%, without any operative mortality. The tumor was located in the vermis in 39% and in the cerebellar hemisphere in 11%; it occupied both locations in 50%. In 47% of the children a ventriculoperitoneal shunt was required. Postoperatively, craniospinal radiation at 3600 cGy with a boost to the posterior fossa was administered. Chemotherapy was used in 56%. The 1-year survival rate was 92%, and survival plateaued at 54% at 5 years. Children less than 3 years of age fared worse than those over 3 years old. While the male-to-female ratio was 1.6:1, there was no gender difference in survival. Chang’s classification was used to grade the tumors. T stage did not have an impact on survival, but M stage did. No statistically significant difference in survival was found between the patients who had a total resection and those who had a subtotal resection. There was no difference in survival in terms of tumor location, hydrocephalus or ventriculoperitoneal shunt. Chemotherapy showed no survival benefit. The recurrence rate was 26%, and its timing followed Collin’s law. Recurrence led to death within 1–9 months. GH deficiency was diagnosed in 5 patients and hypothyroidism in 4 patients. The mean follow-up time was 4.4±3.7 years, with a range of 2.5 months to 16.5 years. Fourteen patients died, 5 were lost to follow-up, and 7 were transferred to adult care without persistent disease. Ten children are presently being followed up by the Neuro-oncology Clinic. Four children continue to be followed through psychology services. Our results are comparable to those in larger series, and are similar to those of the Montreal Children’s Hospital.