Cigarette smoking, blast crisis, and survival in chronic myeloid leukemia

We reviewed the records of all patients with chronic myeloid leukemia (CML) seen in the CML Clinic of the University of Colorado Health Sciences Center between 1968 and 1987 for a history of cigarette smoking. Patients who smoked for five or more pack/years within the ten years preceding, or after the diagnosis of CML, were defined as smokers. Adequate smoking histories were obtained on 122 patients. Eighty-seven of these were non-smokers and 35 were smokers by the above criteria. The smoking group had a higher predominance of males, an older median age, and were diagnosed earlier in the course of the 20 year study. Seventy-two patients had died at the time of analysis. All but one, a non-smoker, died from the development of blast crisis. The overall median actuarial survival was significantly reduced for smokers (35 months) as compared to non-smokers (47 months). This was particularly striking for patients who had succumbed to the disease, with a median survival of 30 months in smokers versus 46 months in non-smokers. Although various explanations could explain the differences noted, we conclude that cigarette smoking has an adverse effect on the development of blast crisis and survival in chronic myeloid leukemia.