Introduction
Neuroblastoma is approximately 9% of all childhood cancers, occurring once out of 8,000 infants and that’s approximately 1 in 105 children less than 15 years of age world-wide. The median age at diagnosis is approximately 22 months with over one-third diagnosed at less than 1 year of age and over 88% diagnosed by the age of 5.
Some studies indicate a bimodal age distribution with one peak at approximately
1 year and the second between 2 and 4 years.
In children under 5 years of age, neuroblastoma usually presents in the abdominalregion involving the sympathetic ganglia of the paraspinalregion or the adrenal gland. In infants under a year of age there is a higher incidence of tumors in the thoracic region. In Stage 1 and 2 neuroblastoma where tumoris confined to the originating organ or surrounding tissue, the prognosis is quite favorable. However in Stage 3 and 4 where tumor extends beyond the midline, is metastatic or involves bony lesions the prognosis for patients is poor. It is possible that early stage disease is a distinct entity from late stage disease because their response rate to therapy and their molecular genetics and biologic characteristics are distinct.
Of all human tumors Neuroblastomas have one of the highest rates of spontaneous tumor regression. This is primarily due to an unusual presentation of neuroblastoma called Stage IVS that occurs in infants under a year of age who present with widely disseminated disease that typically resolves with minimal therapy. Stage IVS tumors have intrigued scientists studying neuroblastoma who feel that an understanding of this disease entity will provide clues to the more devastating presentations of neuroblastoma.
A report of familial NB which affected 4 of 5 siblings lead Knudson and
Meadows to formulate a "Mutation Modelfor Neuroblastoma" in 1976. This model proposed