Population-based study of medulloblastoma: outcomes in Alberta from 1975 to 1996.

BACKGROUND The purpose of this study was to determine incidence, survival rate, and prognostic factors as well as the frequency of Collins' Law Violators (CLVs) in an unselected population of medulloblastoma patients. Collins' Law dictates that 'cure' of a child with a tumor occurs after a period that includes the child's age at diagnosis plus 9 months. METHODS Using the Alberta Cancer Registry a population-based review identified 49 patients with medulloblastoma (19 adults, 30 children) diagnosed from 1975-96. Pathology was reviewed in all cases. All patients had surgical resection, followed by radiotherapy in 47 patients and chemotherapy in 17. RESULTS The overall 5-year survival was 50%. There was a trend for the extent of resection to be associated with a longer survival (Long rank test, p < 0.06) but this was not significant. Tumor recurrence occurred a median of 22.4 months (range, 6.4-192.3) after diagnosis and median survival after recurrence was 9.3 months (range, 0.4-64.9). The survival curve did not appear to plateau but was affected by tumor-related deaths in 3 (21.4%) of the 21 long-term survivors diagnosed in childhood. These three patients had recurrences a mean of 11.7 years after diagnosis and are designated as CLVs. CONCLUSIONS The survival rate in an unselected population of patients with medulloblastoma is poor. Aggressive resection of the tumors prolongs survival. The Collins' Law Violators were relatively common and we suggest this concept be abandoned in medulloblastoma.