Risk Factors of Treatment Related Mortality during Autologous Stem Cell Transplant in Patients with Light Chain Associated Amyloidosis (AL).

Background: High dose melphalan followed by autologous stem cell transplant (ASCT) is an effective treatment of immunoglobulin light chain amyloidosis (AL). However, the high treatment related mortality (TRM, death before day 100) remains a serious concern and is the major drawback of this therapy. A better understanding the risk factors contributing to TRM could help physicians choose the most appropriate therapy for these patients. We performed a retrospective study to identify risk factors that contribute to TRM after ASCT in AL patients.

Methods: All patients who underwent ASCT for AL at our institution from 7/96 to 12/04 were studied. Data were collected on age, sex, septal thickness, glomerular filtration rate (GFR), B2M, CRP, proteinuria, albumin, cardiac troponin T (cTnT) and alkaline phosphate.

Results: A total of 218 patients underwent ASCT for AL during this time period. One patient refused consent for this study. Pretransplant cTnT was available on 161 (73.9%) patients. The overall TRM rate for the 217 patients was 12.4%. By univariate analysis, septal thickness, GFR, albumin, alkaline phosphatase and cTnT were found to be associated with TRM. In the multivariate analysis, only albumin, alkaline phosphatase and cTnT remained independent predictors of TRM. Cutoffs were identified using receiver-operator characteristic (ROC) curve. The cutoff for albumin was 2.85 g/dL, 249 U/L for alkaline phosphatase and 0.02 ng/mL for cTnT. The percentage of patients with low albumin, elevated cTnT and alkaline phosphatase were 51.1%, 20.5% and 12.4% respectively. The TRM rate of patients with low albumin was 18.0%, 27.3% for elevated cTnT and 29.6% for high alkaline phosphatase. Risk of TRM increased significantly with each additional risk factor (Table).

Discussion: In our AL population, low serum albumin, elevated alkaline phosphatase and cTnT were independent risk factors of TRM after ASCT. Patients with 2 or more risk factors are at significant risk of TRM during ASCT. In these high risk patients, alternative therapy should be considered in order to avoid excessively high incidence of TRM.