Age at diagnosis
The effect of age at diagnosis on 5-year survival is profound. According to the 1975 to 2006 U.S. Surveillance, Epidemiology, and End Results (SEER) statistics, the 5-year survival stratified by age is as follows:
- Age younger than 1 year – 90%.
- Age 1 to 4 years – 68%.
- Age 5 to 9 years – 52%.
- Age 10 to 14 years – 66%.
Children of any age with localized neuroblastoma and infants aged 18 months and younger with advanced disease and favorable disease characteristics have a high likelihood of long-term, disease-free survival. The prognosis of fetal and neonatal neuroblastoma are similar to that of older infants with neuroblastoma and similar biological features. Older children with advanced-stage disease, however, have a significantly decreased chance for cure, despite intensive therapy.
Survival of patients with International Neuroblastoma Staging System (INSS) stage 4 disease is strongly dependent on age. Children younger than 18 months at diagnosis have a good chance of long-term survival (i.e., a 5-year disease-free survival rate of 50%–80%),[55,56] with outcome particularly dependent on MYCN amplification and tumor cell ploidy. Hyperdiploidy confers a favorable prognosis while diploidy predicts early treatment failure.[57,58] Infants aged 18 months and younger at diagnosis with INSS stage 4 neuroblastoma who do not have MYCN gene amplification are categorized as intermediate risk and have a 3-year event-free survival (EFS) of 81% and OS of 93%.[7,59,60,61,62]
Adolescents and young adults
Neuroblastoma has a worse long-term prognosis in an adolescent older than 12 years or in an adult compared with a child, regardless of stage or site and, in many cases, a more prolonged course when treated with standard doses of chemotherapy. Aggressive chemotherapy and surgery have been shown to achieve a minimal disease state in more than 50% of these patients.[32,63,64] Other modalities, such as local radiation therapy and the use of agents with confirmed activity, may improve the poor prognosis for adolescents and adults.[63,64]
Site of primary tumor
Site of primary tumor is not an independent prognostic factor. Multifocal (multiple primaries) neuroblastoma occurs rarely, usually in infants, and generally has a good prognosis. Familial neuroblastoma and germline ALK gene mutation should be considered in patients with multiple primary neuroblastomas.