Second malignant neoplasms in children: an update from the Late Effects Study Group.

This paper presents an update from the Late Effects Study Group on 292 cases of second malignant neoplasms (SMN) occurring in individuals who were diagnosed with their first neoplasm in childhood. Data are presented regarding the types of first and second neoplasm, the therapy administered, and the predisposing factors. Of the 292 cases (308 SMN), the most common primary was retinoblastoma followed by Hodgkin's disease, soft-tissue sarcomas, and Wilms' tumor. This is not similar to the relative frequency of these cancers in children but rather reflects specific risk factors. Bone sarcomas were the most common SMN among the 208 SMN developing in previously irradiated sites while acute leukemia was the most common SMN unassociated with radiation. Known predisposing conditions to cancer were present in 73 cases; retinoblastoma was the most common of these, followed by neurofibromatosis. There were ten patients with three and three patients with four malignant neoplasms. In 14 patients, the cause of SMN was not suggested by known risk factors as these patients had negative family histories and received no radiation or chemotherapy. We note, therefore, that although most cases of SMN in survivors of childhood cancer can be attributed to radiation, genetic disease, chemotherapy, or combinations of these, unrecognized predisposition or chance may also play a role.