Long-Term Survival after Autologous Stem Cell Transplantation in a Colombian Population

Introduction: Autologous hematopoietic stem cell transplantation (auto-HSCT) is a complex medical process that has evolved throughout the years, becoming a potentially curative therapy for many hematologic neoplasms and non-malignant marrow disorders, as well as a clinical option for some autoimmune diseases. During the past decades, HSCT has had important advances in technology and technique, patient supportive care, and conditioning protocols, making it a safer procedure. As a result, patient survival rates continue improving. Nonetheless, it is unclear if these improvements are also seen in developing countries. The aim of the present study is to assess survival rate for patients who underwent auto-HSCT in a Colombian population. Methods: A retrospective cohort study was conducted at a tertiary referral center in Colombia, South America, on patients who underwent auto-HSCT between November 2009 and December 2017. Descriptive statistics were used to analyze patient's demographic characteristics. The Kaplan-Meier method was used to assess overall survival (OS) and relapse-free survival (RFS) rates at 100 days, one year, and five years following auto-HSCT. Results: One hundred and fifty-seven patients were included, with a mean age of 49.54 years (range 14-71). Seventy-nine (50.31%) were men. Classifying patients by age group, 68.7% of the patients (n=108) were in the 20-60 years old group and 28% (n=44) were older than 60 years. The most common indication for auto-HSCT was multiple myeloma (42.7%), followed by non-Hodgkin lymphoma (35%) and Hodgkin lymphoma (13%). Peripheral blood stem cells were the graft source in all patients (100%). High-dose melphalan (MEL 200) was the conditioning regimen administered to patients with diagnosis of multiple myeloma, and BEAM (carmustine, etoposide, cytarabine, and melphalan) to patients with lymphoma. OS was 91.7% (CI95% 86.2-95.1) at 100 days, 81% (CI95% 73.9-86.4) at one year, and 60.9% (CI95% 51.3-69.1) at five years. RFS was 94.9% (CI95% 90-97.4) at 100 days, 86.3% (CI95% 79.7-90.8) at one year, and 70.5% (CI95% 66.6-80.7) at five years. Classifying patients by pre-transplantation disease stage as defined by the EBMT study group, OS for early disease was 85.5% (CI95% 75.6-91.8) at one year and 58.2% (CI95% 43.7-70.2) at 5 years, 88.1% (CI95% 76.5-94.1) at one year and 51.8% (CI95% 33.9-66.9) at 5 years for intermediate stage, and 100% at one year and 42.3% (CI95% 7.3-75.4) at 5 years for advanced disease. The mos