Review of 676 second primary tumors in patients with retinoblastoma: Association between age at onset and tumor type

Objective: To obtain a more accurate understanding of second primary tumors (SPTs) by analyzing a large number of SPTs from the published literature. Methods: A literature search was performed to identify published cases of SPTs in patients with retinoblastoma. Patient age, radiation field, tumor location, and tumor type were analyzed for statistical association. Results: The study included 676 SPTs in 602 patients. Median age at diagnosis of SPT was 13.0 years (range, 0.3-60.4 years) for all SPTs, 2.7 years for midline intracranial primitive neuroectodermal tumors, 13.0 years for sarcomas, 27.0 years for melanomas, and 29.0 years for carcinomas. The median age at which SPTs occurred inside the radiation field was younger than that for SPTs occurring outside the radiation field or in patients who did not undergo irradiation (P<.001). Sarcomas occurred more commonly inside the radiation field (P<.001). Melanomas, lipomas, leukemias, and lymphomas occurred more commonly outside the radiation field or in patients who did not undergo irradiation (P<.001). Conclusions: Retinoblastoma patients pass through multiple windows of susceptibility to specific SPTs. This information will aid health care providers in monitoring this high-risk group, and it provides new insights for studying the underlying genetic predisposition to SPTs.