A Practical Guide to Competing Risk Analysis for Transplant and Cell Therapy Research

Competing risks are common in hematopoietic cell transplantation (HCT) and immune effector cell (IEC) therapy research. Competing risks refer to events that cannot co-occur and complicate time-to-event analyses. The typical example of competing risk in the context of HCT and IEC research is treatment-related mortality, which competes with disease relapse. In this primer, we first aim to introduce - in a clinician-friendly fashion - the core concepts underlying the statistical modelling of competing risks. Next, we propose a practical, step-by-step guide to analyze time-to-event outcomes in the context of competing risks using the open access R environment. Relevant R packages are introduced, enabling the generation of publication-ready tables and figures. We hope our manuscript will encourage more robust analyses in the fields of HCT and IEC therapy when competing risks are at play.