How frequent is spontaneous remission of neuroblastomas? Implications for screening.

The 'true' incidence of spontaneous regression of neuroblastomas is uncertain. However, the frequency of spontaneous regression is important when the benefits of screening procedures are considered. In the population-based Danish neuroblastoma survey 1943-80, spontaneous regression was documented in less than 2% of cases. However, the 'true' incidence may be higher. The epidemiological findings of increased incidence and survival rates with an unchanged mortality rate may suggest the inclusion of borderline lesions among 'truly' malignant neuroblastomas in recent decades in Denmark. However, it is more likely to be a result of improved diagnosis, changes in the social composition of the population and possibly unidentified environmental agents. However, if some premalignant lesions in fact had been included, they are most likely to be stages I-II tumours of infancy. In this study we describe cases of spontaneous regression of neuroblastoma from the Danish population-based survey 1943-80.