Characteristics and risk factors of oral mucositis after allogeneic stem cell transplantation with FLU/MEL conditioning regimen in context with BU/CY2

The fludarabine (FLU)/melphalan (MEL) conditioning regimen containing FLU and high-dose MEL was analyzed in comparison with the BU/CY2 regimen to characterize oral mucositis (OM) and risk factors. OM incidence significantly varied between BU/CY2 and FLU/MEL (100 vs 78%, P=0.004), but the incidence of severe OM grades 3–4 WHO and kinetics of OM were fully comparable. Patients with OM persisting on day +21 had more acute GVHD (68 vs 32%, P=0.005), which tended to occur earlier than among those without such prolonged OM. Multivariate analysis showed significant dependency of acute GVHD on severity and prolonged duration of OM and significant correlation between OM severity and its prolonged duration. Body surface area-based dosing in the FLU/MEL regimen led to a wide range of MEL doses administered per kilogram body weight (2.5–5.2 mg/kg, median 3.5). In multivariate analysis, MEL dose per kilogram of body weight was found to be a significant predictor of OM incidence and severity. Female gender and lower body mass index were less important variables than the fact that the actual dose of MEL administered per kilogram of body weight was relatively high when the dosage was calculated on the basis of body surface area.