Why Are Stem Cell Transplants Used as Cancer Treatment?

Stem cells are immature blood cells found in the bone marrow and blood. Even though they start out the same, these stem cells can mature into all types of blood cells (details below). People with certain types of cancer can sometimes be helped by a stem cell transplant to treat or even cure the cancer.

Why would someone with cancer need a stem cell transplant?

Stem cell transplants are used to replace bone marrow that has been destroyed by cancer or destroyed by the chemo and/or radiation used to treat the cancer.

In some cancers, such as certain leukemias, multiple myeloma, and some lymphomas, a stem cell transplant can be an important part of treatment. It works like this: high doses of chemo (sometimes along with radiation), work better than standard doses to kill cancer cells. But high doses can also kill all the stem cells and cause the bone marrow to completely stop making blood cells, which we need to live. This is where stem cell transplants come in. The transplanted stem cells replace the body’s stem cells after the bone marrow and its stem cells have been destroyed by treatment. Transplant lets doctors use much higher doses of chemo to try to kill all of the cancer cells.

A stem cell transplant from another person can also help treat certain types of cancer in a way other than just replacing stem cells. Donated cells can often find and kill cancer cells better than the immune cells of the person who had the cancer ever could. This is called the “graft-versus-cancer” or “graft-versus-leukemia” effect. It means that certain kinds of transplants actually help fight the cancer cells, rather than simply providing normal blood cells.

What are stem cells?

All of the blood cells in your body start out as young (immature) cells called hematopoietic stem cells. Hematopoietic means blood-forming. Even though they’re called stem cells, they are not the same as the embryos’ stem cells that are studied in cloning and other types of research. These stem cells are blood-forming stem cells.

Stem cells mostly live in the bone marrow (the spongy center of certain bones). This is where they divide to make new blood cells. Once blood cells mature, they leave the bone marrow and enter the bloodstream. A small number of stem cells also get into the bloodstream. These are called peripheral blood stem cells.

Stem cell transplants are used to give back stem cells when the bone marrow has been destroyed by disease, chemotherapy (chemo), or radiation. Depending on where the stem cells come from, this procedure may be called:

  • Bone marrow transplant (BMT)
  • Peripheral blood stem cell transplant
  • Cord blood transplant

They can all be called hematopoietic stem cell transplants.

What makes stem cells so important?

Stem cells make the 3 main types of blood cells: red blood cells, white blood cells, and platelets.

We need all of these types of blood cells to keep us alive. For these blood cells to do their jobs, you need to have enough of each type in your blood.

Red blood cells (RBCs) carry oxygen away from the lungs to all of the cells in the body. They bring carbon dioxide from the cells back to the lungs to be exhaled.

A blood test called a hematocrit shows how much of your blood is made up of RBCs. The normal range is about 35% to 50% for adults. People whose hematocrit is below this level have anemia. This can make them look pale and feel weak, tired, and short of breath.

White blood cells (WBCs) help fight infections caused by bacteria, viruses, and fungi. There are different types of WBCs.

  • Neutrophils are the most important type in fighting bacterial infections. The absolute neutrophil count (ANC) is a measure of the neutrophils in your blood. When your ANC drops below 1,000 per cubic millimeter (1,000/mm3) you have neutropenia, and you have a higher risk of infection. The danger is greatest when levels are below 500/mm3.
  • Lymphocytes are another type of white blood cell. There are different kinds of lymphocytes, such as T lymphocytes (T cells), B lymphocytes (B cells), and natural killer (NK) cells. Some lymphocytes make antibodies to help fight infections. The body depends on lymphocytes to recognize its own cells and reject cells that don’t belong in the body, such as invading germs or cells that are transplanted from someone else.

Platelets (thrombocytes) are pieces of cells that seal damaged blood vessels and help blood to clot, both of which are important in stopping bleeding. A normal platelet count is usually between 150,000/cubic mm and 450,000/cubic mm, depending on the lab that does the test. A person whose platelet count drops below normal is said to have thrombocytopenia, and may bruise more easily, bleed longer, and have nosebleeds or bleeding gums. Spontaneous bleeding (bleeding with no known injury) can happen if a person’s platelet count drops lower than 20,000/mm3. This can be dangerous if bleeding occurs in the brain, or if blood begins to leak into the intestines or stomach.

You can get more information on blood counts and what the numbers mean in Understanding Your Lab Test Results.

Deciding to have a stem cell transplant

Although a stem cell transplant can help some patients, even giving some people a chance for a cure, the decision to have a transplant isn’t easy. Like everything in medicine, you make the final choice about whether or not you’ll have a stem cell transplant. Transplant has been used to cure thousands of people with otherwise deadly cancers. Still, the possible risks and complications can threaten life, too. The expected risks and benefits must be weighed carefully before transplant.

Your cancer care team will compare the risks linked with the cancer itself to the risks of the transplant. They will discuss these risks and benefits with you. They may also talk to you about other treatment options like chemotherapy, radiation, or clinical trials. Transplants have serious risks, and patients can die from complications. The stage of the cancer, patient’s age, time from diagnosis to transplant, donor type, and the patient’s overall health are all part of weighing the pros and cons before making this decision.

You’ll want to ask a lot of questions to be sure you understand what’s likely to happen. Some people bring a friend or family member to help them remember what the doctor or transplant team says, remind them of questions they had, and take notes. Some people prefer to record these conversations, if the doctor or nurse agrees to it. Here are some questions you might want to ask. For some of these, you may need to talk to the transplant team or the people who work with insurance and payments for the doctor’s office and/or the hospital:

  • Is a transplant the best option for me? Why? What’s the goal?
  • How many transplants do you do for my kind of cancer every year? What is the success rate?
  • Are there clinical trials I should look into?
  • Are there other treatment options I should think about?
  • What type of stem cell transplant will I have? Why?
  • What’s the chance of finding a good match?
  • What are the chances that the transplant will work?
  • What’s the plan if the transplant doesn’t work?
  • What are the risks of waiting or trying other treatments first?
  • Is stem cell transplant considered experimental for my disease? Why?
  • What are the risks to me?
  • What type of treatment will I need before the transplant?
  • How much will transplant cost?
  • What costs, if any, will be covered by my insurance? How much will I have to pay?
  • Will it cover the costs of finding a donor?
  • Will I be able to have children after the transplant? What are my options if I want to have children later?
  • What side effects might I expect? How bad will they be? How long will they last?
  • What types of medicine or self-care will be used to control side effects?
  • How long might I have to be in the hospital?
  • Will I be able to have visitors?
  • What type of follow-up will be needed? How often?
  • What vaccines will I need to get after transplant and when will I get them?
  • What are the chances that the cancer will come back after transplant?
  • When will I be able to return to work?

Be sure to express all your concerns and get answers you understand. Make sure the team knows what’s important to you, too. Transplant is a complicated process. Find out as much as you can and plan ahead before you start.

It’s important to know the success rate of the planned transplant based on your diagnosis and stage in treatment, along with any other conditions that might affect you and your transplant. In general, transplants tend to work better if they’re done in early stages of disease or when you’re in remission, when your overall health is good. Ask about these factors and how they affect the expected outcomes of your transplant or other treatment.

Many people get a second opinion before they decide to have a stem cell transplant. You may want to talk to your doctor about this, too. Also, call your health insurance company to ask if they will pay for a second opinion before you go. You might also want to talk with them about your possible transplant, and ask which transplant centers are covered by your insurance.

Cost of transplant

Stem cell transplants cost a lot – some estimates say $350,000 to $800,000.

A transplant (or certain types of transplants) is still considered experimental for many types of cancer, especially many solid tumor cancers, so insurers might not cover the cost.

No matter what illness you have, it’s important to find out what your insurer will cover before deciding on a transplant, including donor match testing, cell collection, drug treatments, hospital stay, and follow-up care. Go over your transplant plan with them to find out what’s covered. Ask if the doctors and transplant team you plan to use are in their network, and how reimbursement will work. Some larger insurance companies have transplant case managers. If not, you might ask to speak with a patient advocate. You can also talk with financial or insurance specialists at your doctor’s office, transplant center, and hospital about what expenses you are likely to have. This will help you get an idea of what you might have to pay in co-pays and/or co-insurance.

The National Foundation for Transplants (NFT) provides fund raising guidance to help patients, their families, and friends raise money for all types of stem cell transplants in the US. They can be reached online at www.transplants.org, or call 1-800-489-3863.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Be the Match. Transplant Basics: Understanding transplant and how it works. September 2014. Accessed at https://bethematch.org/Patient/Support_and_Resources/Resource_Library/Learn_resources/An_Introduction_to_Marrow_and_Cord_Blood_Transplant_(PDF).aspx on March 15, 2016.

CostHelper. Bone Marrow Transplant Cost. Accessed at http://health.costhelper.com/bone-marrow-transplants.html on March 16, 2016.

National Cancer Institute. Bone Marrow Transplantation and Peripheral Blood Stem Cell Transplantation. August 12, 2013 Accessed at www.cancer.gov/cancertopics/factsheet/Therapy/bone-marrow-transplant on April 4, 2016.

Last Medical Review: May 11, 2016 Last Revised: May 11, 2016

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