Pretreatment is the high-dose chemotherapy and/or radiation therapy given to a patient before transplantation to remove residual tumor cells and hematopoietic cells from the patient’s body, much like removing crops and weeds from the soil with “herbicides” before planting crops in a field to make room for the bone marrow for subsequent transplantation. The “seeding” is done in preparation for the subsequent transplant.
Different pretreatment protocols are used depending on the type of disease.
Commonly used high-dose chemotherapeutic agents include marilyn, cyclophosphamide, fludarabine, etoposide, marfalan, and cytarabine, which are administered into the patient through a PICC (peripherally placed central venous catheter) catheter or other deep vein catheter.
Some patients in pretreatment also require systemic radiation therapy, which is usually measured and positioned well by a radiation technologist or physician before radiation therapy. In whole-body radiotherapy, the patient receives radiotherapy in the radiotherapy room in different positions, such as sitting or lying down. Depending on the dose of radiotherapy, some patients are treated with 1 session of radiotherapy, while others require 3 to 5 sessions.
In addition to radiotherapy, patients receive adjuvant medications, such as vomiting prevention, gastric protection, liver protection, and fluid replacement. They also receive some antibacterial prophylaxis, graft-versus-host disease prophylaxis, and so on.