Stem Cell Transplant for Cancer
What Is Stem Cell Transplant for Cancer?
A stem cell transplant is a medical procedure for replacing blood cells that have been damaged by cancer or cancer treatments. Stem cells are immature cells produced primarily by bone marrow that develop into three types of mature blood cells: red blood cells, white blood cells, and platelets. The production of mature cells is suppressed by blood cancers, such as leukemia, lymphoma, and myeloma. Healthy stem cells are also destroyed by radiation and chemotherapy treatments for cancer. Stem cell transplants allow the body to resume normal, healthy blood production.
Stem cell transplants are an important weapon in medicine’s war on blood cancers. The cancer experts at Baptist Health can share more about when and how a stem cell transplant can make a difference in the life of a loved one dealing with cancer.
What Types of Stem Cell Transplants Are There?
There are three major types of stem cell transplants. They are differentiated by the stem cell source:
Allogeneic stem cell transplant
In an allogeneic transplant, the stem cells come from a cancer-free donor whose tissues closely match those of the patient. In other cases, the stem cells are collected from umbilical cords donated at birth. Leukemia is often targeted with this type of transplant. One advantage of donor-provided stem cells is their introduction of a novel immune response to the cancer. That same novelty, however, increases the possibility that the recipient may reject the stem cells as invading infectious agents.
Autologous stem cell transplant
The source of the stem cells in an autologous transplant is the cancer patient him or herself. Healthy stem cells are extracted from bone marrow prior to cancer treatment, such as radiation or chemotherapy, which attack healthy as well as cancerous cells. Those same stem cells are then returned to the patient after treatments are completed. This type of transplant is frequently used with lymphoma and myeloma. Because the donor and recipient are the same person, there is very little risk of rejection. At the same time, autologous transplants offer nothing new in the way of immune response, which the cancer has already had success in suppressing.
Syngeneic stem cell transplant
The donor in a syngeneic transplant is an identical twin, which is another avenue for reducing the risk of stem cell rejection. Of course, only a relatively small number of persons in the overall population have identical twins.
Finding a Stem Cell Transplant Donor
To reduce the likelihood of transplant rejection, patients are matched with potential donors beforehand. This is done by comparing proteins, called human leukocyte antigens, or HLAs, that reside on the surface of most cells. HLAs help to identify infectious or invading agents that pose a risk to health (sometimes including cancerous cells originating from within the body).
The goal of matching is to find HLAs that are as close as possible to being identical. Unsurprisingly, the best matches are usually with immediate family members, such as a parent, child, or brother or sister. For various reasons, however, as many as three-quarters of all transplant candidates don’t have a good match within their family. The donor search is then extended to unrelated persons, which can be accessed through an institutionalized donor program. Matching can be a slow process and patience is required; some searches require several weeks or more.
How Does a Stem Cell Transplant Procedure Work?
Only after the stem cell source has been identified can the transplant procedure be scheduled. It takes place in stages, usually over the course of a few weeks. Stem cell transplants are typically performed in hospitals or specialized treatment centers.
Allogeneic Transplant Procedure
An allogeneic transplant involves the following steps:
Stem cell collection: Your medical team will collect stem cells from the donor with the closest match to your own tissues. You may also receive injections encouraging the production of white blood cells as a cautionary measure against infection.
Cancer treatment: Once step one has been accomplished, you’ll undergo treatment for cancer, either chemotherapy, radiation therapy, or both.
Stem cell infusion: Step three involves introducing the donor’s stem cells to your body by means of a catheter.
Precautions: Your doctor might recommend allogeneic stem cell transplant precautions. These precautions include regular hand washing, adhering to a low-microbial diet, and avoiding exposure to infection. Following the precautions for your allogeneic stem cell transplant will help protect you from infections during the high-risk period between conditioning and engraftment.
Recovery: This is followed by a substantial recovery period. You’ll receive antibiotics for your weakened immune system, as well as drugs to diminish the possibility of donor-cell rejection.
Autologous Transplant Procedure
These are the steps for an autologous transplant:
Stem cell collection: You’ll be treated with drugs that accelerate the creation of stem cells in your bone marrow. These cells are then removed from the body, either by an IV line or a catheter.
Cancer treatment: Cancer treatment follows. For patients receiving an autologous transplant, this typically means chemotherapy rather than radiation.
Stem cell infusion: Your newly created stem cells, which have been stored in a medical facility since their removal, will be returned to your body by a transplant catheter.
Recovery: What follows is a substantial recovery period, although usually shorter than if you’d received a donor’s cells. You’ll be treated with antibiotics and other medications during this period.
How Long Does a Stem Cell Transplant Procedure Take?
You can expect to stay in the hospital for several weeks for your stem cell transplant procedure. The process involves a series of tests and multiple steps for the transplant. The tests can take several hours, stem cell harvesting a few days, conditioning up to a week, and the transplant a few hours.
What Are the Side Effects of Stem Cell Transplants?
Recipients of stem cell transplants face a number of medical risks:
- Stem cell rejection, called graft versus host disease, when the transplant donor is someone other than the patient (or an identical twin)
- Weakness and fatigue
- Mouth sores
- Anemia from a diminished supply of red blood cells
Most importantly, stem cell recipients experience a reduced immune response for as long as a year after the transplant takes place.
How Do I Know If My Stem Cell Transplant Was Successful?
There are two chief measures of success with regard to a stem cell transplant, one short term and one long term:
The short-term measure is whether your blood count returns to normal. Following cancer treatment, the overall volume of red blood cells, white blood cells, and platelets in your body will be reduced, leaving you vulnerable to fatigue, infections, and bleeding. A stem cell transplant should enable you to produce a sufficient number of new cells, in their proper proportions, to satisfy the day-to-day demands placed on your hematological system.
Impact on Cancer
The long-term measure is the response of cancer to your stem cell transplant and other forms of therapy. The goal in most cases is to cure the disease. In some cases, however, a remission, or temporary recovery of uncertain duration, is the best that can be reasonably hoped for.
Stem Cell Transplant Recovery
For both an autologous and allogeneic stem cell transplant, you can expect your stem cell transplant recovery to last a month or longer. During this time, you will remain in the hospital under medical supervision. You will also receive antibiotics to protect your weakened immune system and specialized drugs to reduce the potential of donor-cell rejection.
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