Outcome of Outpatient Autologous Hematopoietic Stem Cell Transplantation in Patients with Multiple Myeloma and Relapsed and Refractory Hodgkin Lymphoma. The Experience of King Fahad Specialist Hospital in Dammam, Saudi Arabia

Background: Autologous hematopoietic stem cell transplants (HSCT) is the standard of care for transplant-eligible patients with newly diagnosed multiple myeloma (MM) and patients with relapsed and refractory Hodgkin lymphoma (R/R-HL) who achieve chemosensitivity after salvage therapy. Although autologous HSCT is routinely performed in an inpatient setting, the procedure can safely be performed in an outpatient setting. Methods and materials: A retrospective study of patients with MM and R/R- HL who received outpatient autologous HSCT at King Fahad Specialist Hospital (KFSH) in Dammam, Saudi Arabia between the first of April 2017 and the 31st of January 2022 was performed. Results: Over the study period of 4 years and 10 months, a total of 90 outpatient autologous HSCTs were performed for 79 patients (54 patients with MM; 4 of them received planned tandem autografts and 7 other myeloma patients received second autologous HSCTs for relapsed or progressive disease; and 25 patients with R/R-HL) at our institution. The median ages of patients with MM and those with R/R-HL at HSCT were 50.4 years and 27.8 years respectively. At the presentation of their MM, the following high-risk (HR) features were encountered: stage II and III diseases according to the revised international scoring system (RISS) in 53.7%; adverse cytogenetics in 42.6% and extensive bone involvement in 53.7% of patients. In patients with HL at presentation, 48% of patients had stage IV disease according to Ann Arbor staging classification and 84% of patients had B symptoms. Survival for 100 days post-HSCT for all patients with MM and HL who received outpatient autologous transplants was 100%. For patients with MM, the overall survival (OS) rates at 3 years and 4 years post-HSCT were 80% and 67%, while the progression-free survival (PFS) rates over 3 years and 4 years were 58% and 38% respectively. For patients with HL, the OS at 6 years post-HSCT was 95% while the PFS rates at 3 years and 6 years post-HSCT were 84% and 62% respectively. Conclusion: Outpatient autologous HSCT for patients with MM and HL is safe, and feasible and can lead to short-term as well as long-term outcomes that are comparable to autologous transplantation performed in an inpatient setting. Additional benefits of outpatient autologous include saving beds and reducing hospital costs.