Use of investigational drugs as initial therapy for childhood solid tumors.

Solid tumors are relatively rare in children, but comprise about two-thirds of all malignancies that affect this age group. Most of these tumors respond well to initial treatment, and some (Wilms’ tumor, low-stage Hodgkin’s disease, low-stage rhabdomyosarcoma, and low-stage neuroblastoma) are readily cured with modern therapy. Still, many tumors that respond initially acquire clinical drug resistance, respond poorly to rechallenge with known active agents, and demonstrate a low level of responsiveness to experimental agents. This creates a major therapeutic dilemma for the pediatric oncologist. Although a critical need exists to identify new active agents for many solid tumors in childhood, current primary therapy is frequently quite active even in tumors which have a very high rate of relapse.