DECLINE IN INCIDENCE OF MEDULLOBLASTOMA IN CHILDREN

Background. Medulloblastoma is one of the most common intracranial tum ors in children. The perception that the incidence of this tumor has d eclined is reinforced by a decline in enrollment to international tria ls for the disease. Methods. A retrospective population-based study of children younger than 15 years whose brain tumors were reviewed histo pathologically was performed in the county of Avon, in the southwest r egion of England from 1976 to 1991. Then, the incidence of medulloblas toma was studied in the noncontiguous southwest and northern regions o f England, with a combined childhood population base of 20.0 million c hild years for the period 1976-1991. Results. In Avon, 16 children wit h medulloblastoma presented in the period 1976-1984 and 2 in the perio d 1985-1991, representing a decrease in incidence from 9.6 per million per year to 1.7 per million per year. The incidence of medulloblastom a in the combined southwest and northern regions showed a significant (P = 0.006) decline from 5.5 per million per year in the period 1976-1 984 to 2.8 in the period 1985-1991. Considered individually, the decli ne in the southwest (from 6.2 per million per year to 2.8 per million per year) was significant but that in the Northern region (from 4.7 to 2.7) was not. Conclusions. In this report, a decline in the incidence of medulloblastoma was shown. In a recent case control study, a prote ctive effect of maternal folate, iron, and multivitamin supplementatio n against primitive neuroectodermal tumors, including medulloblastoma was found. The introduction of periconceptional multivitamin supplemen tation in the 1980s may have caused this significant decline in the in cidence of medulloblastoma.