In an autologous transplant, a patient’s own blood-forming stem cells are collected. He or she is then treated with high doses of chemotherapy, or a combination of chemotherapy and radiation. The high-dose treatment kills cancer cells, but also eliminates the blood-producing cells that are left in the bone marrow. Afterward, the collected stem cells are transplanted back into the patient, allowing the bone marrow to produce new blood cells.
Stem Cell Harvesting
In autologous transplantation, physicians usually collect, or “harvest,” stem cells that circulate in the bloodstream, called peripheral blood stem cells (PBSCs).Peripheral blood stem cell harvesting is similar to giving blood and easier than taking cells from a person’s bone marrow, which is sometimes done for allogeneic transplants. It can take place outside of an operating room and does not require general anesthesia.
A few days before the blood collection, you will receive a medication called G-CSF (filgrastim), which forces the stem cells to leave the bone marrow and move into the circulating blood. This may cause flu-like symptoms in the days preceding and following stem cell harvest. You may also experience aches and pain from the medication.
At Memorial Sloan Kettering, stem cells are collected in the blood donor room using an apheresis or leukopheresis machine. Over the course of one to five days, blood is withdrawn from a vein and circulated through the machine, which collects the stem cells; the other components of the blood are then returned to the patient.
Most patients experience no side effects from harvesting and can go back to their regular activities. The stem cells are cryopreserved (frozen) until they are given back to the patient.
Preparing for the Transplant
Once your stem cells have been harvested, you will go through a process called a preparative regimen (also sometimes called conditioning or cytotoxic treatment). In this step, physicians use chemotherapy with or without radiation therapy to kill cancerous cells. Our physicians customize the particular therapies based on your disease and which treatment it is most likely to respond to.
For patients who receive radiation treatment in addition to chemotherapy, Memorial Sloan Kettering researchers have developed a less intensive radiation treatment called hyperfractionated radiation. This approach involves giving small doses of radiation to the whole body, or to the parts of the body containing lymph nodes, two to three times a day over several days. This reduces many of the side effects of more-intensive radiation therapy
The preparative regimen may be given during several days, a week, or more. Patients usually receive the transplant a day or two after their last chemotherapy or radiation dose.
Transplantation and Recovery
Physicians usually transplant the harvested stem cells into the patient’s bloodstream in the same way that they would administer a blood transfusion. Over the following days and weeks, the transplanted stem cells migrate to the marrow space in the bones, where they gradually begin to produce new blood cells.
Between two and three weeks after the transplant, physicians usually begin to detect newly formed blood cells in the patient’s bloodstream. As time passes, a successful transplant graft will produce red blood cells, white blood cells, and platelets.
During the days immediately after transplantation, patients need a great deal of medical support. You may receive transfusions of irradiated blood products, such as platelets and red blood cells, as well as antibiotics to prevent and treat bacterial, viral, and fungal infections, which are most likely to occur in the first three months after transplantation. Patients are also vulnerable to complications of the chemotherapy with or without radiation therapy, which may require additional treatments.
Most patients remain in the hospital for several weeks after the transplant. During this time, precautionary measures are taken to protect against infection. All people who enter the room are required to wear protective gloves and masks, and to wash their hands with antiseptic soap. Sometimes people entering the room need to cover their clothing with clean, disposable gowns. Fresh fruit, flowers, plants, or cut flowers are prohibited from the patient’s room, as these can carry disease-causing molds and bacteria.
Management of Complications
Our researchers are devoting significant efforts to improving the supportive care of patients undergoing autologous stem cell transplantation. Patients who have received high doses of chemotherapy or radiation therapy may develop acute or chronic complications — including infections, bleeding, and anemia — until blood cell production returns to normal. Liver and lung problems can also develop after a transplant.
One possible complication is mucositis, a condition in which the cells that line the mouth and intestinal tract are destroyed by the high-dose chemotherapy with or without radiation therapy. Symptoms include mouth pain and ulcers, abdominal pain, diarrhea, and infection.
Our researchers have also pioneered the use of the serum markers IL-6 and IL-12, which can be measured in patients who develop fever after stem cell transplantation to determine whether the fever is caused by the transplant process or is due to an infection.