Stem Cell Transplants
A stem cell transplant, in combination with high-dose chemotherapy, is a treatment option that offers a chance for durable remission for people with multiple myeloma. Because the chemotherapy attacks all the blood cells in the bone marrow—not just the multiple myeloma cells—a stem cell transplant provides the body with a new source of healthy cells.
Bone marrow transplants are no longer done in multiple myeloma. Instead, almost all transplants in multiple myeloma are now obtained from the blood and are referred to as peripheral blood stem cell (PBSC) transplants.
There are generally two types of stem cell transplant performed for multiple myeloma: autologous stem cell transplant, which uses the patient’s own stem cells, and allogeneic stem cell transplant, which uses stem cells from a donor.
Autologous stem cell transplant
In an autologous stem cell transplant, the stem cells are taken from the patient’s own blood. Most patients with multiple myeloma who are eligible for transplant undergo this type of transplant, as there are typically fewer complications with an autologous transplant than with a transplant that uses donor stem cells.
All patients who are eligible for transplantation are encouraged to have stem cells collected (also known as “harvested”) so the cells are available if they choose to undergo transplantation at some point during the course of the disease.
The cells are stored until they are needed for the transplant. Then the patient receives treatment such as high-dose chemotherapy, sometimes with radiation, to kill the cancerous multiple myeloma cells. Following the chemotherapy or radiation therapy, the stored stem cells are infused back into the patient’s blood.
The transplant procedure may be inpatient or outpatient, depending on the center and/or patient preference.
Allogeneic stem cell transplant
Allogeneic transplant involves transferring stem cells from a matched donor (usually a relative) to a multiple myeloma patient following high-dose chemotherapy or radiation therapy.
In very rare cases, allogeneic transplant can be curative due to the graft-versus-tumor effect, in which the healthy donor cells help destroy the remaining multiple myeloma cells in the patient’s body. However, allogeneic transplant is rarely used in multiple myeloma because the likelihood of risks outweighs the potential benefits. Specifically, there is a high risk for graft-versus-host disease (GVHD) with allogeneic transplant. This potentially serious complication occurs when the donor immune cells see the patient’s tissues as foreign and attack them.
For people who have multiple myeloma and happen to have an identical twin, a special type of allogeneic transplant, called a syngeneic transplant, can be performed. This type of transplant uses the identical twin as the donor, reducing the risk for GVHD and offering the optimal transplant for patients with multiple myeloma.