BONE MARROW TRANSPLANT
Today, the treatment of hematological diseases related to bone marrow, lymphatic system and blood such as lymphoma, multiple myeloma, acute and chronic leukemia, which are common in both adults and children, is of vital importance.
Bone marrow transplantation is one of the most important treatment options for hematological cancers whose treatment rates are increasing day by day. Bone marrow transplantation, called stem cell transplantation, can be performed on both adults and children.
WHAT IS BONE MARROW TRANSPLANTATION ?
Bone marrow is a spongy tissue found inside the bones and contains cells defined as hematopoietic or blood-forming stem cells. Bone marrow stem cells multiply and differentiate when necessary to form blood cells.
Bone marrow transplantation (Stem cell transplantation) is the process of giving stem cells from the patient himself or another person to the patient.
In general, there are 2 types of transplants. The process of returning one's own stem cells is called 'autologous', while the process of giving stem cells from someone else is called 'allogeneic' transplant.
Allogeneic transplantation can be done from an identical twin (sygeneic) or from a perfectly matched mother, father, sibling or non-consensual person. In recent years, transplants from semi-compatible family members have also been made. These transplants from parents, semi-compatible siblings or children are called haploidentic transplants.
WHO IS SUITABLE FOR BMT ?
A bone marrow transplant is done when the patient's marrow is not healthy enough to function properly. This may be due to chronic infections, various diseases, or cancer treatments. Bone marrow transplants may benefit people with diseases such as:
Bone Marrow Failure Syndromes
Congenital Metabolic Errors
Plasma Cell Disorders
Treatment-refractory or Relapsed Solid Organ Tumors
AUTOLOGOUS STEM CELL TRANSPLANT
The aim of autologous transplantation is to allow hematologic recovery after high-dose therapy. Cells are taken from the patient's own bone marrow before chemotherapy and replaced with new ones after cancer treatment. In other words, in some cases, high-dose, intense chemotherapy or radiotherapy is used in cancer treatment. As a matter of fact, cancer treatment can damage our stem cells and immune system. Doctors ensure that the person's own stem cells are collected and frozen before cancer treatment begins. These stem cells, which are stored after cancer treatment, are given back to the person. This process is called stem cell recovery. Autologous stem cell transplantation is mostly used to treat diseases such as lymphoma, solid tumors in children, and multiple myeloma in adults. In autologous stem cell transplantation, the probability of the recipient rejecting the stem cells and the risk of tissue rejection disease (GVHD) is very low. Therefore, autologous stem cell transplant is safer than allogeneic transplants.
ALLOGENEIC STEM CELL TRANSPLANT
Allogeneic stem cell transplantation is the process of stem cell transplantation performed from the sibling, relatives or unrelated donor of the patient, that is, the person to whom the stem cell transplantation will be performed. Allogeneic transplants, unlike autologous transplants, generate a new immune system response to fight cancer. In other words, during the transplantation process, immune system (immune system) cells are also transplanted along with the donor's stem cells. If the lymphocytes of the donor transferred to the patient during the allogeneic transplant perceive some cells that the patient sees as different, they start a war against them, and this may cause 'graft versus host' disease, which causes severe damage to the recipient's organs. In order to reduce the risk of allogeneic stem cell transplantation, drugs that suppress the immune system are given to the patient immediately after the transplantation, and the warrior capacity of the donor's lymphocytes is tried to be suppressed. In order not to start a war due to tissue differences after allogeneic stem cell transplantation, it is desirable to have as close a tissue compatibility as possible between the patient and the donor.
Before undergoing a bone marrow transplant, a series of tests and procedures are performed to assess the patient's general health and ensure that he or she is physically ready for the transplant. Evaluation may take several days or longer. Otherwise, a surgeon or radiologist inserts a long, thin tube (intravenous catheter) into a large vein in the chest or neck. The catheter usually remains in place for the duration of the treatment. The transplant team will use this catheter to deliver the transplanted stem cells, drugs, and blood products to the body.
If a transplant using one's own cells (autologous transplant) is planned, a procedure called apheresis is used to collect blood stem cells. Before apheresis, daily injections of growth factor are administered to increase stem cell production and to transport stem cells into the circulating blood so that they can be harvested.
During apheresis, blood is taken from a vein and circulated in a special machine. The machine separates the blood into different parts, including stem cells. Stem cells are collected and frozen for use during transplantation. The remaining blood is returned to the body.
In a transplant using stem cells from a donor (allogeneic transplant), a suitable donor is searched and, when found, procedures for stem cell harvesting are performed. Stem cells can come from the donor's blood or bone marrow. The transplant team decides which is better according to the patient's condition.
Another type of allogeneic transplant uses stem cells from umbilical cords (cord blood transplant). Mothers can choose to donate their umbilical cord after the birth of their baby. The blood from these cords is frozen and stored in a cord blood bank until a bone marrow transplant is needed.
After the pre-transplant tests and procedures are completed, a process known as the conditioning regimen begins. During conditioning, chemotherapy or radiation is administered to provide the following conditions:
destroying cancer cells
suppress the immune system
Preparing the bone marrow for new stem cells
The conditioning regimen to be taken; It depends on a number of factors, such as disease, general health, and the type of transplant planned.
When new stem cells enter the body, they travel from the blood to the bone marrow. Over time, they multiply and begin to make new, healthy blood cells. While it usually takes a few weeks for the number of blood cells in the body to return to normal, it may take longer for some people.
It is important to closely monitor the patient's condition in the days and weeks after a bone marrow transplant. For this, a number of blood and similar tests can be applied to the patient. Complications such as nausea and diarrhea may be observed and medication may be required to cure them.
After a bone marrow transplant, close medical care is required. If infection or other complications occur, it may be necessary to stay in the hospital for several days or sometimes longer.
The patient may need periodic transfusions of red blood cells and platelets until the bone marrow begins to produce enough of the healthy cells on its own.
Even months or years after transplant, patients may be at higher risk for infection or other complications. Periodic lifelong follow-up appointments should be made to monitor for late complications.
FREQUENTLY ASKED QUESTIONS
When does the transplanted bone marrow start working?
After bone marrow (stem cell) transplantation, it usually takes 10-15 days for the stem cells to start producing blood cells again. During this period, the patient is supplemented with blood cells from the outside. Because the bone marrow will need a transfusion of red blood cells and platelets for the time it takes to produce enough of the healthy cells on its own. Patients are required to come to follow-up visits where blood tests are done to assess their response to the graft. After transplantation, patients may need to be followed for many years to avoid serious problems.
Are there any risks to the health of the bone marrow donor?
Stem cell donation does not harm the health of the donor in any way. The donor is given a specific drug for 5 days to allow the stem cells to enter the bloodstream. As soon as the number of stem cells in the blood reaches the desired level, it is taken like a blood sample from a vein in the arm.
What if the bone marrow doesn't work?
Failure of the bone marrow to function due to any disease causes deficiencies in blood production, which is of vital importance.
In how many days will the bone marrow result come out?
The collection from the donor is performed under general anesthesia and in a sterile environment. The donor can be discharged after being kept under observation for 24 hours after collection. Special needles are used to collect the marrow. These needles allow the dense marrow to be drawn.
Will there be pain when the bone marrow is removed?
Bone marrow is performed under general anesthesia and in a sterile environment. Special needles are used to collect the marrow. These needles allow the dense marrow to be drawn. The donor does not feel any pain.
How long does a bone marrow transplant take?
In sterile operating room conditions, sufficient amount of bone marrow is collected for the recipient with the help of bone marrow removal needles under general or spinal (anesthetized from the waist) anesthesia in accordance with the donor's conditions. The process takes 1-2 hours.