Utilization of Stem Cell Transplantation in Newly Diagnosed Multiple Myeloma Patients Lacking Geographic Proximity to a Transplant Center

Introduction:

Autologous stem cell transplant (ASCT) is considered standard of care in young and fit patients with newly diagnosed multiple myeloma. ASCT has shown to improve depth of response, progression free survival and overall survival compared to systemic therapy alone in myeloma patients (Harousseau et al. New England Journal of Medicine). Proximity to a stem cell transplant center may influence the utilization of this therapeutic option in transplant eligible multiple myeloma patients. Our cancer center did not have a stem cell transplant program in the 100-mile driving radius. The goal of this study was to assess the referral patterns and utilization of ASCT in newly diagnosed, young (age <65 years) multiple myeloma patients in a setting where patients are lacking proximity to a transplant center.

Methods:

The study was an IRB-approved retrospective cohort study. Patients between 18 and 65 years of age at the time of diagnosis who were diagnosed with multiple myeloma between January 1, 2014, and December 31, 2020, were included. Data including age at diagnosis, sex, race, zip code, treatment regimen, clinical data-including referral to a transplant center, stem cell collection and transplant-were collected and analyzed. Staging was calculated using lab values at the time of diagnosis or within 2 weeks of starting treatment. Date of diagnosis was defined as the date of bone marrow biopsy confirming systemic disease. All frequency and descriptive analyses were performed using SPSS Version 26 (Armonk, NY: IBM Corp.)

Results:

There were n = 62 patients that met the study inclusion criteria. Patients were mainly white (86%) and male (58%) with an average age at diagnosis of 55.9 (SD = 6.83) years. All patients (n = 62, 100%) lived at zip codes that were more than 100 miles from the closest transplant center. ISS staging showed 37% (n = 23, 95% CI 25% - 50%), 29% (n = 18, 95% CI 18% - 42%), and 18% (n = 11, 95% CI 9% - 30%) to have stage I, II, and III disease respectively. Twelve patients (n = 12, 19.4%, 95% CI 10.4% - 31.4%) had insufficient data for staging. The most common first line regimens were bortezomib, lenalidomide, and dexamethasone (n = 39, 62.9%, 95% CI 49.7% - 74.8%) and bortezomib, cyclophosphamide, and dexamethasone (n = 13, 21%, 95% CI 11.7% - 33.2%). Most patients (n = 48, 77.4%, 95% CI 65% - 87.1%) achieved a very good partial response or better. Eight (n = 8, 13%, 95% CI 5.7% - 23.9%) patients had refractory disease to first line therapy. Forty-six (n = 46, 74%, 95% CI 62% - 85%) patients were referred for HSCT evaluation, n = 16 (26%, 95% CI 15.5% - 38.5%) patients were not. Of the forty-six (n = 46) patients that were referred, n = 44 (96%, 95% CI 85% - 99.5%) patients had a clinical consultation with the transplant team. Of the entire cohort, n = 36 (58%, 95% CI 44.9% - 70.5%) patients underwent stem cell collection and n = 34 (55%, 95% CI 42% - 68%) patients underwent an ASCT after induction therapy.

Conclusions:

Our study found that more than one third of young patients with newly diagnosed multiple myeloma did not undergo stem cell collection or stem cell transplant. Lack of geographic access to a transplant center may be a contributing factor to the under utilization of this highly effective therapeutic strategy. Further investigation into interventions to improve ASCT referral and completion rates is imperative for improving outcomes for patients in such geographic locations.