Second malignant neoplasms after primary central nervous system malignancies of childhood and adolescence.

The standardized incidence ratios (SIR) and cumulative incidence rates were determined for developing second malignant neoplasms (SMNs) after primary central nervous system (CNS) malignancies occurring during childhood using registry data. A total of 4553 cases of primary CNS malignancies were identified. Forty-six cases developed SMNs, 19 occurring in a previously radiated field. The SIRs of developing second malignant neoplasms were 6.3 and 3.1 for those cases receiving and not receiving radiation therapy, respectively. The 20-year cumulative incidences for developing SMNs were 3.3 and 1.2% for cases receiving and not receiving radiation therapy, respectively. Children surviving CNS malignancies have an increased susceptibility for SMNs.