A hematopoietic stem cell transplant is a type of treatment used for people with multiple myeloma — a blood cancer that affects plasma cells in the bone marrow.

Stem cell transplants have helped many people with myeloma live longer. Today, they’re part of a larger treatment plan that includes new drug combinations and immunotherapies. This might include a newer type of treatment called chimeric antigen receptor (CAR) T-cell therapy, which changes your own immune cells to attack cancer. While stem cell transplants can’t provide a one-time cure, they still play an important role in helping control the disease.

What Are Stem Cells?

Stem cells are special cells that can grow into many types of cells. Hematopoietic stem cells are found in the bone marrow. They make:

• Red blood cells, which carry oxygen
• White blood cells, which fight infection
• Platelets, which help blood clot and stop bleeding

In people with multiple myeloma, cancer cells crowd out healthy cells in the bone marrow. This crowding can cause anemia (low red blood cells), tiredness, and infections.

What Is a Stem Cell Transplant?

A stem cell transplant replaces unhealthy bone marrow with healthy stem cells. The goal is to help your body make new, normal blood cells after strong treatment that kills myeloma cells. In the past, this was called a bone marrow transplant. Today, doctors may use stem cells either from bone marrow or preferably from your blood, which is why the term hematopoietic stem cell transplant is preferred.

Before a transplant, you’ll receive a high dose of chemotherapy. This kills myeloma cells, but it also destroys your bone marrow. Then, the new stem cells are infused back into your bloodstream. They’ll travel to the bone marrow and start making new blood cells. This process is called engraftment.

Types of Stem Cell Transplants

Stem cell transplantation may work differently depending on where and who the new stem cells come from.

Autologous Stem Cell Transplantation

An autologous stem cell transplant uses your own stem cells. They’re collected from your blood before you receive high-dose chemotherapy and then returned to your body afterward. Medicines known as growth factors are given to mobilize your own stem cells in the bloodstream before collection. The new cells travel to the bone marrow and begin making new, healthy blood cells to replace those that were lost.

For people with multiple myeloma, an autologous stem cell transplant is the recommended type of transplant. Current treatment guidelines recommend a multi-pronged treatment approach to be used in combination with the transplant. This includes:

• Induction therapy, or early treatment, including a monoclonal antibody (a lab-made immune protein) to shrink the cancer before the transplant
• High-dose therapy with immune-modulating drugs and steroids to strengthen the response to the transplant
• Maintenance therapy after the transplant to help keep the cancer under control for as long as possible

Together, these steps have been shown to help people achieve deeper remissions (periods when cancer isn’t growing or spreading). Some people with very high-risk disease may have two transplants in a row (called tandem transplants), usually within 3 to 6 months. However, this is usually reserved for people who don’t show a good response to the first transplant.

Allogeneic Stem Cell Transplantation

An allogeneic stem cell transplant uses stem cells from a donor. Hematopoietic stem cells for allogeneic transplants can come from any of the three places where stem cells are found. This includes the bone marrow, peripheral blood (called a peripheral blood stem cell transplant or PBSCT), or umbilical cord blood (called a cord blood transplant).

One of the major risks of an allogeneic stem cell transplant is that the donor cells may attack healthy tissue by mistake. This is a condition known as graft-versus-host disease. Other risks include graft failure, where donor cells don’t grow properly.

Because of these risks, and since modern drug and cell-based therapies can provide better outcomes, allogeneic stem cell transplant is rarely used for multiple myeloma today. Now, allogeneic stem cell transplants are mainly done in clinical trials for younger or high-risk individuals or when other treatments haven’t worked.

Reduced-Intensity Stem Cell Transplants

Sometimes, people who are older or in poor health can’t withstand the side effects of high-dose chemotherapy or radiation. Reduced-intensity transplantations use less aggressive treatments. They may also be called minitransplants or nonmyeloablative transplants.

Undergoing a Stem Cell Transplant

Stem cell transplants aren’t for everyone. Your hematologist-oncologist (a doctor who treats blood cancers) will consider your age, overall health, organ function, and other risk factors before making a decision.

Your doctor will also discuss the pros and cons of stem cell transplantation for multiple myeloma with you. For example:

• Benefits — Longer remission, deeper response, and improved progression-free survival (how long before the cancer comes back)
• Risks — Serious side effects, infections, and a long recovery period

If your doctor decides you’re a good candidate for the procedure, here’s what you can expect.

Preparing for Transplant

You’ll have tests to check your organs, including your heart, lungs, and kidneys. If you’re having an autologous transplant, you’ll also get growth factors. These are medicines that help stem cells move from your bone marrow into your blood.

Your blood is drawn through an intravenous (IV) line in your arm or chest. The stem cells are collected and stored until transplant day. This process typically takes three or four hours.

High-Dose Chemotherapy

Next, you’ll receive a high dose of chemotherapy. This is meant to kill as many myeloma cells as possible and make room in your bone marrow for new, healthy cells to grow. This step is often referred to as conditioning because it prepares your body for the transplant. Conditioning also weakens the immune system, so it won’t reject the new cells.

Stem Cell Infusion

After chemotherapy, your stem cells are thawed and infused into your bloodstream. This process usually takes from 30 minutes to around 2 hours, depending on the volume of stem cells that have to be infused. The cells find their way back to the bone marrow, where they begin to grow.

Recovering From a Transplant

After your transplant, you’ll stay in the hospital for about two to three weeks while your new cells start growing. It usually takes about two to six weeks for your blood counts to recover.

Short-Term Recovery

The first 100 days after a transplant are the most vulnerable period. During this time, you’re at high risk for infections, bleeding, and fatigue (extreme tiredness). You may need blood transfusions, antibiotics, or other medicines to help prevent or treat infections.

Long-Term Recovery

It can take six months to a year for your immune system to fully recover from a stem cell transplant. If you’ve had an allogeneic stem cell transplant, recovery may be even longer. During this time, your doctor will monitor your blood counts and check for minimal residual disease (MRD). These are small numbers of myeloma cells that can remain after treatment. MRD helps predict how well the treatment is working and may one day guide transplant or maintenance therapy decisions.

Side Effects of Stem Cell Transplantation

A stem cell transplant can cause both short-term and long-term side effects. Some may happen during treatment, while others may develop later.

Short-term effects may include:

• Nausea, vomiting, or diarrhea
• Mouth and throat pain from mucositis (inflammation of the digestive tract)
• Fatigue and weakness
• Fever or infection
• Bleeding or bruising
• Anemia (lower levels of red blood cells)
• Engraftment syndrome (fever, rash, and fluid buildup)

Long-term effects may include:

• Infertility or early menopause
• Cataracts or hormonal changes
• Organ damage
• Secondary blood cancers that appear years after treatment (rare)

Your healthcare team will discuss the full range of possible side effects with you and work with you closely to monitor for them.

Life Expectancy After Stem Cell Transplant for Multiple Myeloma

Thanks to modern treatments, people with multiple myeloma are living longer than ever. A large study found that those who had an early stem cell transplant stayed in remission for about five and a half years before the cancer came back. Those who had triplet therapy (without a transplant) — which includes the drugs lenalidomide, bortezomib, and dexamethasone — stayed in remission for about four years.

Even so, both groups had about the same overall survival. On average, 80 percent of people were still alive five years after their diagnosis when they kept taking maintenance therapy. So, having a transplant early can help control the cancer better. However, many people may live just as long by having a transplant later.

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On MyMyelomaTeam, people share their experiences with multiple myeloma, get advice, and find support from others who understand.

Are you considering a stem cell transplant, or have you recently undergone this procedure? What was your experience like? Let others know in the comments below.