In a stem cell transplant, a person gets high-dose chemotherapy to kill the cells in their bone marrow (where new blood cells, including myeloma cells, are made). Then the person gets an infusion of new, healthy blood-forming stem cells to replace the ones that were killed.
When stem cell transplants were first developed decades ago, the new stem cells were taken from the bone marrow, so this was known as a bone marrow transplant (BMT). Now, stem cells are more often collected from blood (known as a peripheral blood stem cell transplant (PBSCT)). These stem cells are likely to start working faster, and they're less likely than bone marrow cells to be contaminated with a person's myeloma cells.
On this pageA stem cell transplant (SCT) is a common treatment for multiple myeloma, especially in people who are younger and otherwise fairly healthy. It can often help people live longer than if they get just get drug treatments alone.
There aren't strict criteria for who can get a stem cell transplant. But in general, people might be able to get a transplant if they're in fairly good health, are able to do most daily activites on their own, and don't have serious liver or heart disease.
People generally get at least several months of treatment with medicines before getting a SCT. This can help lower the number of myeloma cells in the bone marrow and blood, help with a person's symptoms, and help organs recover from damage the myeloma might have done.
Some people might have the option to either get the transplant at this point (early SCT), or continue to be treated with medicines and wait until the myeloma progresses before getting the transplant (late or delayed SCT). In general, early transplants are more likely to be helpful in the short term, although it's not clear that they help people live longer than delayed transplants.
Several factors are taken into account when deciding which approach might be best, including a person's preferences. For some people, doctors might favor one approach over the other. For example, doctors often advise an early transplant if the myeloma is 'high risk' (because of certain gene or chromosome changes in the myeloma cells) or if a person is older.
A stem cell transplant can be either autologous or allogeneic, depending on who is donating the stem cells for the transplant.
For an autologous SCT, the person’s own stem cells are removed from the bone marrow or peripheral blood before the transplant. The cells are frozen and stored until they are needed for the transplant. At the time of the transplant, the person gets treatment with high-dose chemotherapy to kill the myeloma cells. When this is complete, their stored stem cells are given back to them as an infusion into their blood through a vein. The stem cells then travel to the bone marrow and start making new blood cells.
This is by far the most common type of transplant used for multiple myeloma.
Although an autologous transplant can make the myeloma go away for a time (even years), it's very unlikely to cure it.
Some doctors might recommend that certain people with multiple myeloma get 2 autologous transplants, typically 3 to 6 months apart. This approach is called a tandem transplant or double transplant.
This may help some people more than a single transplant, especially if the myeloma is 'high risk' (because of certain gene or chromosome changes in the myeloma cells). A drawback of this approach is that it causes more side effects and as a result can be riskier.
In an allogeneic SCT, the person with myeloma gets blood-forming stem cells from another person – a donor. The best treatment results occur when the donor’s cells are closely matched to the patient’s cell type and the donor is a close blood relative, such as a brother or sister.
Allogeneic transplants might be better at fighting the cancer than autologous transplants, but they are much riskier. In studies of people with multiple myeloma, those who got allogeneic transplants have often done worse in the short term than those who got autologous transplants.
At this time, allogeneic transplants are not considered a standard treatment for multiple myeloma, but they may be done as a part of a clinical trial.
The early side effects from a stem cell transplant (SCT) are similar to those from chemotherapy, although they may be more severe because of the high doses used. One of the most serious side effects is low blood counts, which can lead to risks of serious infections and bleeding.
A serious side effect from allogeneic transplants is graft-versus-host disease (GVHD). This occurs when the new immune cells (from the donor) see the patient’s tissues as foreign and attack them. GVHD can affect any part of the body and can be life threatening.
To learn more about stem cell transplants, including how they are done and their potential side effects, see Stem Cell Transplant for Cancer.
For more general information about side effects and how to manage them, see Managing Cancer-related Side Effects.