• Diseases&Conditions
• Procedures & Tests
• Injuries & Symptoms
• Special Topics
• Nutrition

• upper arm
• lower leg
• ribs
• breast bone
• vertebra of the spine

• red blood cells that carry oxygen
• white blood cells that fight infection
• platelets, which are cells that help blood to clot

The bone marrow is especially sensitive to high doses of radiation and/or chemotherapy that are needed to destroy certain types of cancer. In addition, sometimes the cancer has invaded the bone marrow itself and replaced many of the immune cell precursors (stem cells) with cancer cells.

Thus, if high enough doses of radiation and/or chemotherapy to kill an individual's cancer are to be given, the bone marrow cells must be replaced by normal ones afterwards, or the person will be left with no source of red blood cells, white blood cells, and platelets, and no functioning immune system.

The solution to this problem is bone marrow transplantation. It can be approached in two ways. If a person is in remission from the malignancy but expected to relapse without further treatment, the person's normal marrow can be harvested (with a needle, usually from the hip bone) during the remission, and stored. Then high dose chemotherapy and radiation (known as "induction" therapy) can be administered, and the person's stored marrow reinfused as a replacement.

Alternatively, if a willing donor who is closely matched in terms of cell genetic markers can be found, that person's marrow can be harvested surgically (again, usually from the hip bone) and infused instead of the person's

In either case, the marrow is infused into the bloodstream by vein, so it can travel to the marrow sites within the bones, and hopefully establish itself and begin to grow new, normal cells.

Sometimes, marrow transplantation is performed on individuals who do not have a malignancy, but suffer from a genetic condition in which they lack an enzyme needed for normal metabolism. The same marrow transplant procedure (from a donor) is used; if the new cells implant successfully, the person has received a lifelong supply of the enzyme he or she lacked.

Who is a candidate for the procedure?

Conditions that may benefit from a bone marrow transplant include the following:

• aplastic anemia, a condition in which damaged or destroyed stem cells in the bone marrow limit production of red blood cells
• bone marrow depression, where the bone marrow has been damaged by treatments such as chemotherapy or radiation therapy
• a variety of cancers, especially the blood cancers called leukemia and lymphoma
• inherited blood disorders, such as thalassemia
• some immunodeficiency disorders, such as severe combined immunodeficiency syndrome, a rare inherited condition
• inherited enzyme deficiency conditions such as Hurler's syndrome

How is the procedure performed?

What happens right after the procedure?

To recover from a bone marrow transplant, a person first needs to survive the few days to weeks from the time of the transplant until the new immune system takes hold, without succumbing to infection or bleeding. The person has essentially no immune protection during this time, so he or she is kept in strict protective isolation.

Next, the person must successfully engraft the transplanted cells. Until this happens, the person is dependent on transfusions to keep him- or herself alive. Then, if the marrow was received from a donor, there is the possibility that immune cells in the new marrow may attack the person's normal cells, a phenomenon known as "graft vs. host" disease. This problem can usually be kept under control with suppressive medications, but again, this aggravates the susceptibility to infection that the person already has.

Finally, the person and his or her healthcare professionals have to trust that the induction did a thorough enough job of destroying the cancer, that it will not recur.

Bone marrow transplantation is a very delicate balance with threats to the person's life on every side, but for some people, it is the only hope of survival.

What happens later at home?

Recovery from a bone marrow transplant depends on many factors. These include the underlying disease and the body's reaction to the procedure. Healthcare professionals will need to monitor the person closely for a few months after the procedure and decide on a process for gradually returning the individual safely to regular activities.

What are the potential complications after the procedure?

The bone marrow donor has a very low risk of complications during and after the procedure. But the things that might occur include:

• severe bleeding
• infection
• reactions to anesthesia

In addition to the major clinical problems outlined above, the bone marrow recipient may suffer from the side effects common to other people who receive chemotherapy and radiation: hair loss, nausea, vomiting, fatigue, and other symptoms.