Poor survival of treatment-related acute nonlymphocytic leukemia

Population-based data on more than 1 million patients registered in the Surveillance, Epidemiology, and End-Results Program of the National Cancer Institute, 1973 to 1984, were analyzed to determine the survival of patients with de novo acute nonlymphocytic leukemia (ANLL) and following a first primary tumor treated (with chemotherapy and/or radiation therapy) or untreated. Cases that occurred within 12 months of the first malignant neoplasm were excluded. Survival was estimated using Cox proportional-hazards modeling, with age, sex, and specific type of ANLL as covariates. The 6271 patients with de novo ANLL had an estimated 12-month survival of 30%, while the 107 patients with treatment-related ANLL (radiation therapy, 60; chemotherapy, 29; both, 18) had an estimated 12-month survival of 10%. This is not due to lingering effects of the first tumor since ANLL following solid tumors not treated with chemotherapy or radiation therapy (118 cases) has similar survival (estimated 12-month survival, 36%) as de novo ANLL. We conclude that ANLL that occurs after chemotherapy or radiation therapy is biologically more aggressive and/or resistant to therapy than spontaneous ANLL. This provides a rationale for current studies on treatment-induced cellular changes and on more aggressive therapy for these patients.