A Systematic Literature Review of the Long-term Risk of Haematological Malignancy in Unrelated Peripheral Blood Stem Cell Donors.

Please note: this is a retrospective registration of a systematic review. Allogeneic Haematopoietic Stem Cell Transplantation (HSCT) is an effective and curative therapy for a wide range of haematological diseases. Peripheral blood stem cells (PBSCs), mobilised using granulocyte-colony stimulating factor (G-CSF), are the most commonly used stem cell source for allogeneic transplantation, including donations from matched unrelated donors. Concerns have previously been raised regarding the long-term safety of G-CSF administration in healthy donors, particularly regarding the potential risk of haematological malignancy. Although existing evidence suggests that the incidence of such malignancies in PBSC donors is low, limitations of earlier studies include relatively short follow-up durations, loss to follow-up, and the inclusion of related donors who may share underlying genetic risk with recipients. Since the completion of earlier reviews, additional long-term follow-up data from donor registries and donation centres have been published. This systematic review re-evaluated the long-term risk of haematological malignancy in unrelated peripheral blood stem cell donors who received G-CSF mobilisation, synthesising evidence from observational cohort and registry-based studies. The aim was to inform donor selection practices, support accurate risk communication, and contribute to the ongoing evaluation of donor safety. The review was conducted as part of an MSc research project, with initial searches completed in August 2024. The protocol is being registered retrospectively on the Open Science Framework prior to journal submission, and updated searches will be conducted to capture newly published evidence.