Increased Risk of Skin Cancer in 1,851 Long-Term Retinoblastoma Survivors

Patients with hereditary retinoblastoma are at risk for developing cutaneous melanoma, but little is known about the role of sun exposure or other factors, and the incidence of nonmelanoma skin cancer (NMSC) is poorly understood. We investigated the incidence of melanoma and NMSC in a cohort of 1,851 White, long-term retinoblastoma survivors (1,020 hereditary and 831 nonhereditary) diagnosed during 1914‒2006. During follow-up through 2016, 33 hereditary and 7 nonhereditary survivors developed melanoma, and 26 hereditary and 9 nonhereditary survivors developed NMSC. Most NMSCs were on the head/neck, whereas melanomas were more broadly distributed with patterns similar to melanoma-prone families. For both outcomes, the median age at diagnosis was ~20 years younger among hereditary survivors than among nonhereditary survivors. At 50 years after retinoblastoma diagnosis, the cumulative incidence in hereditary survivors was 4.5% for melanoma and 3.7% for NMSC; for nonhereditary survivors, it was 0.7% and 1.5%, respectively. Sun sensitivity and phenotypic characteristics generally did not vary by skin cancer status. Hereditary retinoblastoma survivors have an increased risk for melanoma and NMSC that occurred earlier than that observed among nonhereditary survivors, likely reflecting genetic factors. These findings among White retinoblastoma survivors support consensus-based recommendations for skin cancer screening and sun protection starting at young ages and continuing long term.