Association Between Autologous Stem Cell Transplant and Survival Among Californians With Multiple Myeloma

Abstract

Background: Autologous hematopoietic stem cell transplant (aHSCT) is an efficacious treatment for newly diagnosed multiple myeloma patients. However, as rapid advances have resulted in other highly efficacious and less intensive therapies, the role of aHSCT has been questioned.

Methods: We utilized population-based data to identify 13 494 newly diagnosed patients younger than age 80 years between 1998 and 2012. Patient characteristics of aHSCT and non-aHSCT groups were balanced using inverse probability weighting of a propensity score predicting aHSCT use. Multivariable models adjusted for baseline comorbidities, demographics, and socioeconomic status estimated the adjusted hazard ratio (aHR) and 95% confidence intervals (CIs) of death.

Results: Twenty point eight percent (2807) of patients underwent aHSCT, and this rate increased over time from 15.4% in 1998-2002 to 23.9% in 2008-2012. aHSCT was utilized among 37.6% and 11.5% of patients younger than age 60 years and 60 to 79 years, respectively. The median time to aHSCT was 9.4 months, and 89% of all aHSCTs occurred within two years of diagnosis. The median overall survival from time of aHSCT was 72.9 months (95% confidence interval [CI] = 68 to 78). Autologous HSCT at any time was associated with improved survival (aHR = 0.83, 95% CI = 0.75 to 0.92). Among aHSCT recipients, transplant more than 12 months after diagnosis (vs ≤12 months) was associated with worse survival (aHR = 1.33, 95% CI = 1.16 to 1.51). The positive effect of aHSCT on overall survival was similar across study time periods and age groups.

Conclusion: In the era of highly efficacious induction therapies, aHSCT remained infrequently used but continued to be associated with improved survival for multiple myeloma patients and should be considered for newly diagnosed patients.

Figure 1.

Diagram of patient identification and selection. aHSCT = autologous hematopoietic stem cell transplant; CCR = California Cancer Registry; DX = diagnosis; RLNSEX = record linkage number; SES = neighborhood socioeconomic status.

Figure 2.

Overall survival from time of autologous hematopoietic stem cell transplant (aHSCT). Autologous hematopoietic stem cell transplant patients were matched to non-aHSCT patients in a ratio of up to 1:2 on age at diagnosis, sex, race/ethnicity, neighborhood socioeconomic status, and comorbidities. Survival times are estimated using the Kaplan-Meier method from the date of transplant among aHSCT patients. Each non-aHSCT patient had to be alive at the time of the matched transplant, and survival times were estimated from this point forward. Differences between the survival curves were tested using the two-sided log-rank test. aHSCT = autologous hematopoietic stem cell transplant.