RISK OF CANCER AMONG OFFSPRING OF CHILDHOOD-CANCER SURVIVORS

Background Increasing numbers of children with cancer survive and reac h reproductive age. However, the risk of cancer (other than retinoblas toma) in the offspring of survivors of childhood and adolescent cancer is uncertain. Methods Using data from national cancer and birth regis tries, we assessed the risk of cancer among 5847 offspring of 14,652 s urvivors of cancer in childhood or adolescence diagnosed since the 194 0s and 1950s in Denmark, Finland, Iceland, Norway, and Sweden. The off spring were followed up for a diagnosis of cancer for 86,780 person-ye ars, and standardized incidence ratios were calculated.Results Among t he 5847 offspring, 44 malignant neoplasms were diagnosed (standardized incidence ratio, 2.6; 95 percent confidence interval, 1.9 to 3.5). Th ere were 17 retinoblastomas, yielding a standardized incidence ratio o f 37. There were 27 neoplasms other than retinoblastoma (standardized incidence ratio, 1.6; 95 percent confidence interval, 1.1 to 2.4). The second most common primary site of cancer among the offspring was the brain and nervous system, in which eight tumors were observed (standa rdized incidence ratio, 2.0; 95 percent confidence interval, 0.9 to 3. 9). There were between zero and four apparently sporadic cases of canc er in other primary sites among the offspring. Excluding 4 likely case s of hereditary cancer and 2 subsequent cancers among the offspring wi th hereditary retinoblastoma, there were 22 sporadic cancers, for a st andardized incidence ratio of 1.3 (95 percent confidence interval, 0.8 to 2.0). Conclusions There is no evidence of a significantly increase d risk of nonhereditary cancer among the offspring of survivors of can cer in childhood. (C)1998, Massachusetts Medical Society.