RESUMO
Studies were made on the appearance of second malignant tumors (SMT) in children followed in a pediatric hospital at metropolitan Santiago, Chile, between years 1968 and 1987. A retrospective analysis identified SMT in 7 of 430 patients who survived a childhood cancer (incidence 1.62%). An 8th patient was added, whose first neoplasm was treated in another hospital. The initial diagnosis in the affected children were medulloblastoma, neuroblastoma, Wilm's tumor retinoblastoma, Ewing's sarcoma, Hodgkin's disease and, in two cases, acute lymphocytic leukemias. The age range was 6 months to 11 years. Treatment was done by surgery in 5/8, chemotherapy in 7/8 and radiotherapy in all patients. The latent period between the diagnosis of the first cancer and the diagnosis of the SMT was 3.5 to 12 years (median 8.5 years). Osteosarcomas were the most frequent SMT (5/8). The other SMT were a rhabdomyosarcoma, a non Hodgkin lymphoma and an astrocytoma. The majority of SMT were located in the area of prior radiotherapy (6/8). In the other two cases, one had an osteosarcoma, after a bilateral retinoblastoma, which grew outside the previously treated area, and the last one consisted of a lymphoma which was identified 9 years after an acute lymphocytic leukemia. Only 3/8 SMT patients are alive after 14.21 and 34 months follow up. The other children died between 11 and 20 months after diagnosis of SMT. Notwithstanding these kinds of outcome, benefits of therapy for patients with primary tumors greatly outweight the later risk of cancer induction in a small proportion of them.