Incidence of acute nonlymphocytic leukemia, preleukemia, and acute myeloproliferative syndrome up to 10 years after treatment of Hodgkin's disease.

During the period from 1970 to 1981, 391 nonselected patients with Hodgkin's disease were staged and treated with chemotherapy or radiotherapy or both at the Finsen Institute, Copenhagen. Secondary acute nonlymphocytic leukemia or its earlier stages--preleukemia or an acute myeloproliferative syndrome with cytopenia and specific cytogenetic abnormalities of the bone marrow--were observed in 17 patients. A Kaplan-Meier estimate of the cumulative probability of leukemic complications was 3.9 +/- 1.3 per cent (mean +/- S.E.M.) five years after the start of treatment, and 9.9 +/- 2.9 per cent at nine years. All 17 cases of leukemic complications occurred among the 312 patients treated with chemotherapy or combined-modality therapy, whereas no case was observed among 79 patients treated exclusively with radiotherapy (P = 0.003). A significantly increased risk of leukemic complications was observed in chemotherapy-treated patients 40 years old or older (P = 0.001). Despite the observed relatively high risk of secondary leukemia, the rate of death from progressive Hodgkin's disease, nonleukemic complications, and unrelated causes still far exceeds the rate of leukemia-related deaths in these patients.