The effect of smoking on allogeneic transplant outcomes

Using the Center for International Blood and Marrow Transplant Research (CIBMTR) data, we compared the transplant outcomes of patients with chronic myelogenous leukemia (CML) who were nonsmokers (NS) and past or current smokers (PCS). There were 2193 NS and 625 PCS who received matched sibling and unrelated donor allografts for CML in first chronic phase. We looked for dose effects and identified low and high dose smoking groups (>10 pack years, >1 pack per day). Outcomes were adjusted for known prognostic variables including the European Group for Blood and Marrow Transplant (EBMT) risk score. In multivariate analyses of sibling allograft recipients, relapse risk (RR) was higher (RR=1.67, P=.003) in smokers than NS, but the dose effects were not consistent. High-dose smokers experienced a 50% treatment-related mortality (TRM) versus 28% in the NS group at 5 years on univariate analysis, and the RR was 1.57 (P=.005) on multivariate analysis. Overall survival (OS) at 5 years was 68% in NS versus 62% in the low-dose smoking group versus 50% in the high-dose smoking group (P < .001). Smoking did not significantly affect outcomes in unrelated donor recipients, but numbers were smaller. High-dose smoking is associated with a reduction in OS in patients having sibling allografts for CML. A prospective study with detailed demographic, pulmonary function, and quality-of-life data would improve our understanding of this issue.