A stem cell transplant (also known as a bone marrow transplant) lets doctors give higher doses of chemotherapy, sometimes along with radiation therapy.
The doses of chemotherapy drugs are normally limited by the side effects these drugs can cause. Higher doses can’t be used, even if they might kill more cancer cells, because they would severely damage the bone marrow, where new blood cells are made.
But with a stem cell transplant, doctors can give high doses of chemo because the patient receives a transplant of blood-forming stem cells to restore the bone marrow afterwards.
Stem cell transplants are sometimes used to treat lymphoma patients who are in remission or who have a relapse during or after treatment. Although only a small number of people with lymphoma are treated with this therapy, this number is growing.
Types of stem cell transplants
There are 2 main types of stem cell transplants (SCTs) based on where the stem cells come from.
- In an autologous stem cell transplant, the patient’s own stem cells are used. They are collected several times in the weeks before treatment. The cells are frozen and stored while the person gets treatment (high-dose chemo and/or radiation) and then are given back into the patient’s blood by an IV (catheter in the vein).
- In an allogeneic stem cell transplant, the stem cells come from someone else (a donor). Usually this is a brother or sister, although the source may be an unrelated donor or umbilical cord blood. The donor’s tissue type (also known as the HLA type) needs to match the patient’s tissue type as closely as possible to help prevent the risk of major problems with the transplant. Regardless of the source, the stem cells are frozen and stored until they are needed for the transplant.
Autologous SCTs are used more often than allogeneic SCTs to treat lymphoma. Still, using the patient’s own cells may not be an option if the lymphoma has spread to the bone marrow or blood. If that happens, it may be hard to get a stem cell sample that is free of lymphoma cells.
Allogeneic transplants are used less often for lymphoma because they can have severe side effects that make them hard to tolerate, especially for patients who are older or who have other medical problems. It can also be hard to find a matched donor.
A stem cell transplant is a complex treatment that can cause life-threatening side effects. If the doctors think a person might benefit from a transplant, it should be done at a cancer center where the staff has experience with the procedure and with managing the recovery phase.