Second malignancies complicating Hodgkin's disease: a Southwest Oncology Group 10-year followup.

Thirty-two second malignancies (21 acute leukemias and 11 solid tumors) were identified among 659 patients with all stages of Hodgkin's disease treated by members of the Southwest Oncology Group. There were no leukemias and one solid tumor among 95 patients treated with radiotherapy alone. The actuarial risk of developing acute leukemia at 7 years was 6.2% for chemotherapy alone, 6.4% for combined modality, and 7.7% for salvage chemotherapy. The incidence of acute leukemia was higher (P = 0.002) among those whose treatment began at greater than or equal to 40 years of age. The actuarial risk of leukemia in that group was 20.7% at 7 years. These data are compatible with the hypothesis that chemotherapy alone, combined modality, and salvage chemotherapy have an equivalent oncogenic potential and that patients greater than or equal to 40 years of age have an enhanced susceptibility to these oncogenic stimuli.