Watch the Cancer.Net Video: Bone Marrow and Stem Cell Transplantation: An Introduction, with Sonali Smith, MD, adapted from this content.

Key Messages:

Stem cell transplantation is a procedure that is most often recommended as a treatment option for people with leukemia, multiple myeloma, and some types of lymphoma. It may also be used to treat some genetic diseases that involve the blood.

During a stem cell transplant diseased bone marrow (the spongy, fatty tissue found inside larger bones) is destroyed with chemotherapy and/or radiation therapy and then replaced with highly specialized stem cells that develop into healthy bone marrow. Although this procedure used to be referred to as a bone marrow transplant, today it is more commonly called a stem cell transplant because it is stem cells in the blood that are typically being transplanted, not the actual bone marrow tissue.

The purpose of bone marrow and hematopoietic (blood-forming) stem cells

Bone marrow produces more than 20 billion new blood cells every day throughout a person's life. The driving force behind this process is the hematopoietic (pronounced he-mah-tuh-poy-ET-ick) stem cell. Hematopoietic stem cells are immature cells found in both the bloodstream and bone marrow. These specialized cells have the ability to create more blood-forming cells or to mature into one of the three different cell types that make up our blood. These include red blood cells (cells that carry oxygen to all parts of the body), white blood cells (cells that help the body fight infections and diseases), and platelets (cells that help blood clot and control bleeding). Signals passing from the body to the bone marrow tell the stem cells which cell types are needed the most.

For people with bone marrow diseases and certain types of cancer, the essential functions of red blood cells, white blood cells, and platelets are disrupted because the hematopoietic stem cells dont mature properly. To help restore the bone marrows ability to produce healthy blood cells, doctors may recommend stem cell transplantation.

Types of stem cell transplantation

There are two main types of stem cell transplantation:

Autologous transplantation (AUTO). A patient undergoing an AUTO transplant receives his or her own stem cells. During the AUTO transplant process, the patients stem cells are collected and then stored in a special freezer that can preserve them for decades. Usually the patient is treated the following week with powerful doses of chemotherapy and/or radiation therapy, after which the frozen stem cells are thawed and infused into the patient's vein. The stem cells typically remain in the bloodstream for about 24 hours until they find their way to the marrow space, where they grow and multiply, beginning the healing process.

More here:
What is Stem Cell/Bone Marrow Transplantation? | Cancer.Net