Risk of nonocular cancer among retinoblastoma patients and their parents. A population-based study in Denmark, 1943-1984.

The risk of nonocular cancer among survivors of retinoblastoma has been investigated in a population-based study in Denmark, 1943 to 1984. None of the survivors had been treated with chemotherapeutic drugs. Forty-eight patients were treated with x-rays, and 102 patients were treated primarily with surgical removal of the eye(s). The overall relative risk (RR) for a new primary cancer was 4.2 (95% confidence limits, 1.1-11.5). In the subgroup of genetic retinoblastoma the risk was 15.4 (95% confidence limits, 2.6-50.8) and in the group of nonhereditary cancer the risk was 1.7 (95% confidence limits, 0.1-8.5). For all retinoblastoma patients the RR of bone cancer was 100 (95% confidence limits, 17-330). Parents not having retinoblastoma themselves were not at increased risk for nonocular cancer.