Second malignant neoplasms in survivors of childhood cancer.

As the treatment of childhood cancer continues to improve, the number of survivors at risk for late effects rises. One such late effect is the risk of second malignant neoplasms. Large multicenter registries have been established to accumulate data on the incidence of second cancers. Relative risks and cumulative risks can now be calculated for retinoblastoma, Wilm's tumor and Hodgkin's disease. Early data are now available for leukemia, sarcomas and central nervous system tumors. Genetic cancer syndromes, radiation therapy and treatment with chemotherapeutic agents are known risk factors for second malignant neoplasms in survivors of childhood cancer.