Second malignancies after treatment of Hodgkin's disease: the influence of treatment, follow-up time, and age.

Abstract

PURPOSE In the period 1968 through 1988, The Norwegian Radium Hospital (NRH) treated an unselected population of 1,152 patients with Hodgkin's disease (HD) that comprised more older patients (mean age, 43 years) than most other institutions. We considered it important to evaluate these patients for development of second cancers (SCs). PATIENTS AND METHODS The Norwegian Cancer Registry identified previously untreated patients with HD treated at NRH who had developed a SC more than 1 year after diagnosis of HD. The relative risk ratio (RR) (observed/expected cases) and the cumulative risk were calculated. RESULTS Sixty-eight patients had developed a SC, including nine acute nonlymphocytic leukemias (ANLLs), eight non-Hodgkin's lymphomas (NHLs), and 51 solid tumors, including 11 lung cancers. The RR of SC and leukemia was 1.86 (95% confidence interval [CI], 1.4 to 2.4) and 24.3 (95% CI, 11.1 to 46.2), respectively. The RR of SC was highest in younger patients (< 41 years, RR = 3.8). No significant association between splenectomy and development of ANLL was found. The influence of treatment and follow-up time on the development of SC agrees with data from other large cancer institutions. CONCLUSION (1) The low RR of developing a SC in this study is probably due to the number of older patients included, who have a lower RR of developing a SC due to less aggressive treatment, shorter follow-up time, and higher incidence of cancer in the expected background population. (2) The low RR and cumulative risk of developing ANLL may be due to the limited use of extensive chemotherapy (CT) in our hospital in the earlier years.