Extramedullary relapse after allogeneic bone marrow transplantation for haematological malignancy

Area of Science:

• Hematology
• Oncology
• Transplantation Immunology

Background:

• Extramedullary (EM) relapse is a significant complication following allogeneic bone marrow transplantation (alloBMT).
• Understanding risk factors and treatment outcomes for EM relapse is crucial for improving patient prognosis.
• Previous studies have not fully elucidated the specific characteristics and survival associated with EM relapse compared to marrow-only relapse.

Purpose of the Study:

• To identify risk factors associated with extramedullary relapse after alloBMT.
• To describe the natural history and treatment response of EM relapse.
• To compare the prognosis of EM relapse with marrow-only relapse in patients with hematological malignancies.

Main Methods:

• Retrospective analysis of 183 patients undergoing alloBMT for hematological malignancies.
• Evaluation of relapse patterns, including extramedullary and marrow-only relapse.
• Statistical analysis to determine independent risk factors and survival outcomes.

Main Results:

• Fifteen out of 51 relapsed patients experienced EM relapse (alone or with marrow involvement).
• Chronic graft-versus-host disease (GVHD) and a longer interval between transplant and relapse were linked to increased EM relapse risk.
• EM relapse was associated with longer post-relapse survival and responsiveness to cytotoxic therapy, but not donor lymphocyte infusion (DLI).

Conclusions:

• Extramedullary relapse after alloBMT may be more frequent than previously recognized.
• Chronic GVHD is a risk factor for delayed EM relapse, despite a lower overall relapse risk.
• EM relapse appears to have a more favorable prognosis compared to marrow-only relapse, with distinct treatment responses.