Cancer among 1,348 offspring of survivors of childhood cancer.

The occurrence of cancer among the 1,348 offspring of 2,441 survivors of childhood cancer, treated before 1978, was investigated. Information was obtained through a questionnaire sent to the general practitioners of these survivors. Twenty-three of 52 offspring born to survivors of heritable retinoblastoma developed retinoblastoma; the heritable form of retinoblastoma is known to be transmitted to offspring as an autosomal dominant. None of the 94 offspring born to the 54 survivors of unilateral retinoblastoma with no family history of the disease have developed the disease. This implies that it is unlikely that more than 9% of survivors of unilateral retinoblastoma with no family history have the germ-cell mutation; consequently it is unlikely that more than 4% of their offspring will be affected. Among the 1,199 offspring born to 629 survivors of other childhood malignant disease, who produced children, one acute monocytic leukaemia and one acute lymphoblastic leukaemia were observed. This is more than expected on the basis of the general population (one-tailed p = 0.04). However, the types of cancer observed in these 2 offspring and their parents conform to a previously described familial aggregation of cancers. Only a small number of children were born to survivors who received therapy that was potentially germ-cell mutagenic, and thus it is not possible to make any accurate estimation of their risk of malignant disease.