Global Epidemiology of Post-Transplant Lymphoproliferative Disorder (PTLD) in Hematopoietic Stem Cell Transplantation (HSCT): A Systematic Review and Meta-Analysis of Incidence, Subtypes, Risk Factors, and Beyond

Background: Hematopoietic stem cell transplantation (HSCT) is a procedure used in different malignant and non-malignant diseases. Although post-transplant lymphoproliferative disorder (PTLD) is infrequently observed in patients with HSCT, no study on the overall global incidence rate is available to date. Methodology: In this study, we selected 39 studies from 941 studies from three databases (i.e., PubMed, ScienceDirect, and Google Scholar) to identify the global incidence rate of PTLD in HSCT. Results: The pooled incidence was determined to be 5.6% (95% CI: 5.0 to 6.3) and rose further to 12.4% (95% CI: 10.2 to 14.7) after excluding outlier studies. The quality of the studies was high as well. PTLD was prevalent the most in allogenic HSCT (i.e., 5.6% (95% CI: 4.9 to 6.3)) and within the European region (i.e., 27.1% (95% CI: 21.4 to 32.8)). Among risk factors, human leukocyte antigen (HLA) mismatch was reported in most of the studies. Conclusions: This study assessed and discussed the overall global incidence of PTLD in HSCT patients, continent-based incidence, and risk factors that can be helpful in finding the possible prevention mechanism of PTLD and implementing individualized treatment approaches based on the treatment availability during HSCT.