Hematopoietic Stem Cell Transplantation - Comorbidity Index in Patients with Multiple Myeloma for Autologous Transplantation: A Valuable Tool for Predicting Overall Survival

Abstract

Introduction: The scoring system of the hematopoietic cell transplantation comorbidity index (HCT-CI) was used in patients with Multiple Myeloma (MM) undergoing ASCT, and it could predict progress-free survival and overall survival.

The primary endpoint of our study is to determine the ideal cut-off value for the HCT-CI score, which can be effective in showing overall survival in patients with MM undergoing ASCT.

Methods: The X-tile model was used to determine the cut-off values of the HCT-CI score. Survival probabilities were calculated by using the Kaplan-Meier estimator. Univariate and multivariate analysis was performed using Cox proportional hazard regression model.

Findings: By using the X-tile model according to the HCT-CI score, patients were divided into 2 categories according to OS: HCT-CI Score ≤6 as low-risk (n:93, 81.6%), HCT-CI score >6 as high-risk (n:21, 18.4%).

The median duration of survival could not be reached for the low-risk group and the entire cohort, but it was 22 months for high-risk patients. One-year and 2-year OS rates were 96.7% and 86.9% in the low-risk group; 69.9% and 40.3% in the high-risk group (p<0.001), respectively. In multivariate regression analysis, only being >70 years old and HCT-CI >6 were found to be significant with an HR 3.718 and 5.543, respectively.

Discussion: HCT-CI score >6 can aid physicians to decide ASCT in MM patients and predict the overall survival of patients. Since similar survival times can be achieved with current combination therapies (monoclonal antibodies, etc.) in these patients, ASCT may not be considered.