Multiple myeloma, and the powerful chemotherapy drugs used to treat it, can wreak havoc on healthy blood and bone marrow stem-cells. Once cells are damaged, patients' immune systems may never be able to fully recover. A myeloma stem-cell transplant can restore blood cells to their original condition and function following chemotherapy treatments. In most cases, doctors prefer to harvest healthy stem-cells from patients before aggressive chemotherapy begins and later re-infuse them back into their bodies, a process called an autologous stem-cell transplant. Donor stem-cells can also be used if autologous transplant is not possible, though the procedure is generally less effective.
Patients who have been diagnosed with multiple myeloma but are still in relatively good health are the best candidates for myeloma stem-cell transplant. In most cases, a person will undergo at least one cycle of chemotherapy first to see if his or her cancer starts responding. If results are promising, stem-cell transplant can be considered before more potent and aggressive drugs are administered.
In the past, collecting stem-cells involved a tedious, painful procedure in which multiple bones were aspirated with long needles. Most clinics today utilize medications called growth factors that promote the development and early release of bone marrow stem-cells into the bloodstream. Blood can then be drawn nearly pain-free from a vein in the chest with a catheter. Laboratory experts then isolate stem-cells from the blood, freeze them, and infuse the remaining blood back into the patient's catheter. The collection procedure usually takes about three hours.
Chemotherapy can continue once stem-cells are harvested and stored. Drugs such as melphalan, which is very effective against myeloma but also devastating to stem-cells, can be administered without fear of permanently damaging bone marrow. Depending on the patient's response, it may take several rounds of chemotherapy before the myeloma stem-cell transplant can be performed.
The myeloma stem-cell transplant procedure is relatively straightforward. A bag of harvested stem-cells is thawed and connected to the same catheter that was used in the collection process. Over the course of several hours, stem-cells are reintroduced to the bloodstream. It may take up to two weeks for all of the harvested stem-cells to be replaced. The stem-cells gradually make their way back to bone marrow, where they once again take up their original function of producing new, healthy blood cells.
Most patients respond well following autologous myeloma stem-cell transplant. Regular blood tests and bone marrow biopsies following the procedure can confirm the success of treatment. It is possible for cancer to return, even if it appears to be completely removed after chemotherapy and a transplant, so several rounds of treatment are occasionally necessary.