conditioning regimen
A preparative treatment protocol administered before stem cell transplantation to eliminate malignant cells and suppress the immune system.
Full Definition
A conditioning regimen consists of high-dose chemotherapy, radiation therapy, or both, administered prior to hematopoietic stem cell transplantation to achieve multiple objectives: eradication of malignant cells, immunosuppression to prevent graft rejection, and creation of marrow space for donor stem cell engraftment. Regimens are classified as myeloablative (completely destroys bone marrow), reduced-intensity (less toxic but still immunosuppressive), or non-myeloablative (minimal direct anti-tumor effect). Selection depends on patient factors including age, comorbidities, disease status, and transplant type. Common agents include cyclophosphamide, busulfan, fludarabine, and total body irradiation.
Usage
Usage note: Should not be confused with induction therapy, which is initial treatment to achieve remission, or maintenance therapy given post-remission.
In Context
- "The patient tolerated the myeloablative conditioning regimen with manageable toxicities." — Transplant summary
- "A reduced-intensity conditioning regimen was selected due to the patient's advanced age." — Treatment planning