RISK OF SUBSEQUENT MALIGNANT NEOPLASMS AMONG 1,641 HODGKINS-DISEASE PATIENTS DIAGNOSED IN CHILDHOOD AND ADOLESCENCE - A POPULATION-BASED COHORT STUDY IN THE 5 NORDIC COUNTRIES

Purpose: To assess the risk of subsequent malignant neoplasms among Ho dgkin's disease patients diagnosed before 20 years of age in the five Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden). Pati ents and Methods: There were 1,641 Hodgkin's disease patients identifi ed through the national cancer registries since the 1940s or 1950s. Th e patients were monitored for 17,000 person-years until the end of 199 1. Expected figures were derived from the age-specific incidence rates in each country and standardized incidence ratios (SIR) were calculat ed. Results: A total of 62 subsequent neoplasms were diagnosed (SIR, 7 .7; 95% confidence interval [Cf], 5.9 to 9.9). The overall cumulative risk of subsequent neoplasms was 1.9% at the 10-year follow-up point, 6.9% at 20 years, and 18% at 30 years. There were 26 subsequent neopla sms among males (SIR, 6.5; 95% CI, 4.3 to 9.6) and 36 among females (S IR, 8.9; 95% CI, 6.2 to 12), of which 16 were breast cancers (SIR, 17; 95% CI, 9.9 to 28). High risks were seen for thyroid cancer (SIR, 33; 95% CI, 15 to 62), for secondary leukemia (SIR, 17; 95% CI, 6.9 to 35 ), and for non-Hodgkin's lymphoma (SIR, 15; 95% CI, 4.9 to 35). The re lative risk increased from 3.3 (95% CI, 1.2 to 7.1) for Hodgkin's dise ase patients diagnosed in the 1940s and 1950s to 15 (95X CI, 7.4 to 27 ) in the 1980s. The highest risk of secondary leukemia (SIR, 68; 95% C I, 18 to 174) was seen among those diagnosed with Hodgkin's disease in the 1980s. Conclusion: Patients who survive Hodgkin's disease at a yo ung age are at very high relative risk of subsequent malignant neoplas ms throughout their lives, In particular, the high relative risk of br east cancer following Hodgkin's disease in the teenage years calls for enhanced activity for early diagnosis. (C) 1996 by American Society o f Clinical Oncology.