The treatment of blood diseases and cancers, including allogeneic stem cell transplants, is now highly specialized. The "conditioning regimen" is the chemotherapy treatment for the recipient of the donated stem cells to prepare the body to most effectively receive the donated cells.
You will read about the intensity of the conditioning referred to as "Myeloablative" regimens and "Reduced Intensity" or "Non-myeloablative" regimens. The standard approach for decades was to completely destroy all the cells in the patient's bone marrow (called "myeloablation"). Radiation is included for some patients. Not only does the chemotherapy kill the bad cells, a lot of damage can occur to healthy cells, including bodily organs.
Newer chemotherapy combinations are studied and used to maximize the effectiveness of the transplant while minimizing the risk and harm to the patient. These are called "reduced intensity conditioning" (RIC) regimens, and are usually given to older patients (over 60 years of age).
There are many studies underway to determine optimal treatments for overall survival and minimal Graft vs. Host Disease across patient age, gender, and cytogenetic risks.
Some factors transplant physicians consider when determining each patient's conditioning regimen:
1. Patient's age
2. Underlying cancer & cytogenetic risk factors
3. Other co-morbidities (health issues)
4. Patient's mobility, fitness before transplant
5. Response to treatment
There is still much to be learned. Each option has its potential risks and benefits. Physicians are continually balancing multiple risks throughout a patient's transplant journey.
As a patient, I came to believe that SCT decisions are a combination of science, physician experience, and art. The decisions are well beyond what a patient can contemplate. Ask questions, but don't expect to fully understand all the implications. Trust in your doctors and focus on taking care of your body, mind, and spirit as you embark on the biggest ride of your life. You can do it!