Bone Marrow and Stem Cell Transplantation

Autologous or allogeneic bone marrow transplantation (BMT) and peripheral blood stem cell transplantation (PBSCT) are procedures that rebuild the supply of normal stem cells that are destroyed by high-dose chemotherapy and/or radiation therapy. In autologous transplantation, the bone marrow or blood stem cells are collected from the patient. In allogeneic transplantation, the bone marrow or blood stem cells are collected from a related or unrelated (non-family) donor.

In bone marrow transplant, stem cells are taken from inside the donor or patient's hip bone. In peripheral blood stem cell transplantation, the cells are collected and drawn from the blood and not the bone marrow. During the transplant procedure, patients receive large doses of anti-cancer drugs, alone or in combination with radiation, in order to destroy as many cancer cells as possible prior to receiving bone marrow or stem cells.

Although high-dose chemotherapy and/or radiation therapy is often very effective, this treatment also destroys normal stem cells in the blood and bone marrow. Bone marrow and peripheral blood stem cell transplantation provide replacement of these normal stem cells and "rescue" the patient from the effects of high-dose chemotherapy or radiation therapy. Autologous and allogeneic bone marrow or autologous and allogeneic stem cell transplantation is a complex process that can take several weeks to months to complete. Listed below are the major steps involved in the transplant process and the common side effects associated with them.

Collection: Bone marrow or blood stem cells are collected from the patient or donor. Your doctor will explain which procedure is best for you. Collecting stem cells from the bone marrow is usually done in a hospital operating room under general or spinal anesthesia. Using a hollow needle, a surgeon will take bone marrow from several areas on the hipbones. In most cases, the only side effect of the procedure is some soreness in the hip area for a few days.

Collecting stem cells from blood can often be done as an outpatient and no general anesthesia is needed. A medication called a colony-stimulating factor or "growth factor" is administered to increase the number of stem cells in the blood prior to collection. Blood is collected through a process called apheresis. A catheter is inserted into the vein and blood is circulated through the apheresis machine, which removes the part of the blood containing stem cells and returns the remaining blood back to the patient through a separate catheter in another vein.

The process is usually completed in one or two sessions. Each session can last from two to four hours. The most common side effects experienced during stem cell collection are slight dizziness and tingling sensations in the hands and feet. Less common side effects include chills, tremors, and muscle cramps. These temporary side effects are relieved by medications.

Processing: The collected blood or bone marrow is processed in the laboratory. A technique called purging may be considered to remove and discard cancer cells and isolate the healthy blood stem cells for later infusion. This process is used only with autologous transplants. Check with your physician to see if purging can be used for you.

Cryopreservation: If blood or marrow needs to be preserved or frozen for use at a later time, a preservative called dimethyl sulfoxide (DMSO) is used. The cells may be frozen for a prolonged period of time if necessary. This is usually done with autologous transplants.

High-dose Therapy: High-dose chemotherapy and/or radiation therapy is administered to the patient. This treatment is designed to destroy cancer cells more effectively than standard chemotherapy by giving patients higher doses of anti-cancer medicines to kill the lymphoma cells. High-dose chemotherapy can cause severe side effects, which will require most patients to be admitted to the hospital for treatment and in order to be closely monitored.

Shortly before starting chemotherapy, large amounts of fluid are given intravenously to prevent dehydration and possible damage to the kidneys. Medications designed to prevent or lessen some of the expected side effects are also given. Some of the more common temporary side effects caused by the high-dose chemotherapy are nausea, vomiting, diarrhea, mouth sores, skin rashes and hair loss. The severity of side effects such as nausea and vomiting can now be reduced or prevented by medication.

Reinfusion: Stem cells are thawed and given back to the patient. Within a few days after completing the high dose therapy, the stored stem cells or bone marrow is transplanted, or put back, into the patient's bloodstream. It usually takes half an hour to two hours to infuse stem cells. If dimethyl sulfoxide (DMSO) was used in the cell freezing process, the most common temporary side effects of the reinfusion process may include mild nausea and vomiting, mild abdominal cramping, chills or flushing, and an unusual odor or taste of garlic. In rare cases, DMSO may cause low blood pressure, a fast or slow heart rate, or shortness of breath. Medications are given before the reinfusion process to prevent or lessen some of the effects of DMSO.

Engraftment and Recovery: Transplanted stem cells or marrow begin to produce new blood cells in 7-14 days. During the first few weeks after transplantation, the reinfused stem cells or marrow move through the blood stream to the bone marrow where they begin the process of producing new blood cells, including white blood cells, red blood cells and platelets. This process is called engraftment. Until engraftment is complete, the patient is at risk for infection from having too few white blood cells, which help fight infection. The patient is also more likely to bleed from decreased platelets needed for clotting.

Fatigue is also a concern because red blood cells, which carry oxygen throughout the body, are at low levels. Even a minor infection can lead to serious problems, because the body's immune system is so weakened by the effects of the high-dose chemotherapy and the loss of blood cells. Friends and family should be discouraged from visiting if the patient or one of the visitors is not feeling well. Your health care team will discuss guidelines for patient care in order to prevent infections.

It is important for you and your caregivers to be active participants in the recovery process. Ask to speak to your transplant coordinator about the transplant procedure and its possible side effects. High-dose chemotherapy and bone marrow or blood stem cell transplantation can place enormous stress on patients and families. Support services offered through the hospital and many other organizations are very important during this time. Request to see the social worker if you have questions regarding various support organizations.

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