There are three types of stem cell transplants: autologous, allogeneic, and syngeneic. There is also something called a tandem transplant which we will explain below. 

• Autologous Stem Cell Transplant (ASCT) is when your own stem cells are collected and stored, and then given back to you after you receive high-dose chemotherapy. This is the primary focus of this guide as it is the most common transplant for those with multiple myeloma. 
• Allogeneic Stem Cell Transplant (Allo HSCT) is when you receive a donor’s stem cells. The donor can be related to you or completely unrelated to you from a donor registry.
• Syngeneic Transplant occurs when the patient receives stem cells from an identical twin.
• Tandem transplant typically means that two ASCTs are performed back to back in the context of myeloma treatment. This is also known as a double autologous transplant.
• It is also possible that someone has a combination of these, such as a ASCT followed up with an allo or syngeneic treatment. Talk to your doctor about which option is right for you.

Autologous Stem Cell Transplant (ASCT) 

The current standard-of-care stem cell transplant in multiple myeloma treatment is the autologous stem cell transplant, which starts with collecting the patient’s healthy stem cells. 

After undergoing high-dose chemotherapy to kill the myeloma cancer cells, the patient becomes very vulnerable to infections as chemotherapy kills more than just the cancer cells. Patient’s own healthy stem cells are given back to help the body quickly rebuild the blood and immune system.

Because this type of stem cell transplant is the main focus of the guide, you will continue to learn about the procedure as we go along. 

Allogeneic Stem Cell Transplant

Allogeneic stem cell transplants are occasionally used in myeloma. However, for the standard myeloma patient, this is usually used as a last resort option and is becoming less frequent as more advances are being made in the myeloma treatment field. 

Syngeneic Transplant

Syngeneic stem cell transplantation is a procedure where a patient receives blood-forming stem cells—cells that give rise to all types of blood cells—from their healthy identical twin.

While uncommon due to their nature, it’s a viable option for identical twins in myeloma treatment. 

Tandem Transplant

At times, doctors will recommend a tandem (back-to-back) autologous stem cell transplant. While less of a popular procedure now, some stem cell transplant specialists will still recommend this method for high-risk myeloma patients.

In the case of tandem transplants, the healthy stem cells are collected only once, ideally sufficient to perform three ASCTs. The stem cells are then frozen until they are given back to the patient. 

The period of time between the first transplant and the second one is typically about three to six months. This recovery period is necessary to strengthen the body for the second transplant. 

The myeloma specialist and the transplant specialist work together, along with other members of the healthcare team, to decide when the patient is ready for the first and second transplants. 

A patient’s general state of health is the most important factor for the tandem transplant decision. If there are medical conditions that make the transplants risky, these need to be addressed before the transplants.

There are cases, where a patient stays in remission for over 10 years after a tandem transplant, and the third batch of the frozen stem cells are used again for a third SCT procedure, but due to recent events and a plentitude of approvals, the third procedure is less common.

Sometimes, a tandem transplant refers to an autologous transplant and then an allogeneic transplant. These cases are rare but worth mentioning to your doctor, especially if you have high-risk myeloma.