Childhood medulloblastoma in Denmark 1960-1984 - A population-based retrospective study

Medulloblastoma is a common paediatric brain tumour, located in the cerebel lum and in the IV ventricle, surpassed in frequency only by astrocytomas. 1 80 children below the age of 15 with a medulloblastoma of the posterior fos sa were treated in Denmark in the 25-year period from 1960 to 1984 and foll owed up until the end of 1996, or until death. During the 25 years they acc ounted for 20% of all intracranial tumours in children in Denmark. All tumo urs were histologically verified. The mean annual incidence was 6.4x10(-6), decreasing slightly with a factor of 0.12x10(-6) per year. The male/female ratio was 2.1 - twice that of the background population of children (1.05) . The 5-year survival rate following diagnosis, surgery and radiotherapy wa s 23%, and the 25-year survival rate was 16%. The 5-year survival rate was 8% in the first 5-year period of 1960-1964, increasing to 36% in the last p eriod 1980-1984. Presumably the increase in survival depends on many factor s, e.g. improved diagnostic methods and neuroanaesthesia, better operative technique (microscope), improvements in radiotherapy and the introduction o f chemotherapy. The best predictive factors of a good prognosis were preope rative CSF shunting, radical tumour removal and complete radiotherapy, i.e. irradiation of the brain, tumour bed and spinal cord. The survival rate in the last five-year period was seven times higher than the survival rate fo und in a comparable Danish study from the years 1935-1959. Most of the chil dren followed Collins law of risk index. The results of treatment in childr en with medulloblastoma remain unsatisfactory. Accordingly, participation i n international prospective studies of multimodal treatment should be encou raged, possibly using chemotherapy prior to surgery.