Approximately 12,400 children and adolescents younger than 20 years are diagnosed with cancer each year in the United States,1 and childhood cancer remains the leading cause of disease-related mortality in children.2 Malignant solid tumors account for approximately 30% of childhood cancers.1 The predominant histologies of specific solid tumors vary significantly with age.3 The overall distribution of pediatric solid tumors by histologic subtype is shown in Figure 123.1.

Figure 123.1. Distribution by histologic types of the most common pediatric tumors and subtypes of solid tumors in patients under 20 years of age.

Surveillance, Epidemiology, and End Results 1986–1995. GCT, granulosa cell tumor.

The outcomes of patients with solid tumors has dramatically increased during the past 30 years, and this success can be attributed to several factors, including enrollment of patients into well-designed prospective clinical trials (Fig. 123.2),4,5 systematic collection of tissue to better define the biology of disease,6 availability of more effective chemotherapy agents, use of multimodal therapy, better supportive care, and more refined diagnostic imaging methods that accurately define the extent of disease at diagnosis.

Figure 123.2. Overall survival rates for childhood rhabdomyosarcoma according to treatment era.

IRSG, Intergroup Rhabdomyosarcoma Study Group.