Stem cell transplants or bone marrow transplants are considered to be an effective form of treatment for some types of cancer, namely leukemia, lymphoma, multiple myeloma and neuroblastoma. While high doses of chemotherapy and radiation are used widely to treat cancer, these forms of treatment, while killing the cancer cells, can also destroy the healthy bone marrow where blood cells are formed. The transplant therefore works to replenish the bone marrow and healthy cells, after the body goes through radiation and chemotherapy. This allows the bone marrow to start producing new blood cells again, which in some cases are also able to fight and destroy any cancerous cells that might not have been destroyed through the initial treatment procedures. Some of the forms of cancer that can be effectively treated through stem cell or bone marrow transplants have been enumerated below:
- Multiple Myeloma
Multiple myeloma is a blood cancer that originates in the plasma cells located in the soft spongy tissue in the bone marrow. Plasma cells are white blood cells and are responsible in producing antibodies, also known as immunoglobins, critical in maintaining the immune system of the human body. When an individual is infected with multiple myeloma, these healthy plasma cells are transformed into malignant myeloma cells, which divide rapidly and soon grow out of control. The rapid growth of these cells do not allow normal cells enough space to grow in the bone marrow and start invading the hard exterior of the bone, soon spreading into the cavities of the bone, forming tumours. When there is only one tumour, it is known as a solitary plasmacytoma and multiple myeloma when there are multiple tumours.
An autologous stem cell transplant is commonly used to treat multiple myeloma. The patient undergoes a drug treatment before the stem cell transplant to reduce the number of myeloma cells in the body. In an autologous transplant the existing good stem cells are taken from the patient themselves, which are then frozen and stored and only given back to the patient after he/she has undergone chemotherapy or radiation to destroy the cancerous cells. An autulogous transplant is recommended for patients less than 70 years of age and performed either at the time of initial diagnosis of the disease or during a relapse. While neither chemotherapy or an autologous transplant guarantees an absolute cure, the chances of survival with the disease is prolonged in case of a transplant, than it would be with just chemotherapy. Patients with multiple myeloma are often recommended two autologous transplants, known as tandem transplants, 6-12 months apart and is known to help patients more than a single procedure. This however could be riskier and have side effects.
- Acute Myeloid Leukemia
Acute myeloid leukemia or AML is a kind of blood cancer that results in the rapid growth of white blood cells in the bone marrow, and interfering with normal cell growth. The bone marrow normally makes blood stem cells that become mature over time and grow into a myeloid stem cell or a lymphoid stem cell. While a lymphoid stem cell becomes a white blood cell, a myeloid stem cell can become either a red blood cell to carry oxygen, a white blood cell to fight infection or a platelet to form blood clots to prevent bleeds.
When a person is infected with AML, the myeloid stem cells start forming immature white blood cells called myeloblasts that prevent the formation of normal cells as is required by the body. Sometimes the stem cells also result in the growth of abnormal red blood cells and platelets. The unnatural growth of these cells is known an leukemia and since they build up in the blood and bone marrow, there is no place for the growth of healthy cells in the body. The leukemia cells then also spread outside the blood and can infect other organs like the nervous system including the spine and the brain, the skin and the gums.
An allogeneic stem cell transplant is one of the preferred ways to treat acute myeloid leukemia. In an allogeneic treatment, the stem cells are harvested from a matching donor, which could include a family member or even a saved umbilical cord. An allogeneic transplant is preferred to an analogous one in case of an AML since the disease is related to the blood and the bone marrow. In such cases, giving back the patient his/her own cells as is done in an analogous treatment might mean transferring back some cells which might still be leukemia infected. The allogeneic treatment is also useful since the donor cells are new to the body and in the process of adapting to the graft body, the new cells recognize any existing leukemia cell as foreign and destroys them.
However, it is important to remember that the allogeneic stem cell transplant also has its share of risks and side effects, the most common risk being of finding a matching donor. Also since the allogeneic mode of treatment requires foreign cells to be injected into the body, these new cells can also attack and destroy some of the healthy cells of the patient. This mode of treatment is therefore recommended for younger patients.
- Chronic Lymphocytic Leukaemia
Producing Chronic lymphocytic leukemia or CLL is a type of blood cancer that affects the growth of white blood cells. In healthy bodies the white blood cells produce immunoglobins or antibodies to help fight infection or disease. When affected with CLL, instead of producing immunoglobins these cells become cancerous and become leukemia cells. CLL is not a fast growing cancer and if detected in the early stages do not need very rigorous modes of treatment, which usually starts once the disease begins to progress. There are a wide range of treatments available for CLL in its early stages including antibiotics and platelet and blood transfusion to restore the level of red blood cells and platelets in the body.
In a progressed stage of CLL, allogeneic stem cell transplants are used to treat the disease. While high doses of chemotherapy can diminish the number of leukemia infected cells, there is a chance that the disease might recur even if the signs of leukemia are not visible. In such cases higher doses of chemotherapy is not advisable because it could also damage the bone marrow and new blood cells that are forming in it. An allogeneic stem cell transplant therefore helps doctors to use higher dose of chemotherapy with radiation to help treat the infection. This ensures that after the radiation and chemotherapy are finished, the patient is given fresh set of blood forming cells that can restore the bone marrow and help the growth of new cells.
- Aplastic Anaemia
Aplastic anaemia is a condition wherein the bone marrow is damaged and unable to produce any new blood cells. This results in a deficiency of all three types of blood cells in the human body – white blood cells, red blood cells and platelets. While it is a rare disorder, it is also a serious one and can develop very suddenly without any definite cause. If detected in time aplastic anaemia can be treated successfully through blood transfusions, medicines or an allogeneic stem cell transplant.
- Sickle Cell Anaemia
Sickle cell disease is a condition in which a person has abnormal haemoglobin known as S haemoglobin in their red blood cells. The disease is an inherited one and is passed through by genes from parents to children. SCD infected people inherit two abnormal haemoglobin genes, one from each parent, one of which causes the body to produce S haemoglobin in the body. When someone has two S haemoglobin genes, the disease is known as sickle cell anaemia.
Red blood cells are normally disc-shaped and flexible and can travel through blood vessels to deliver oxygen to tissues. When a person is infected with sickle cell anaemia, the haemoglobin forms stiff rods within the red blood cell, making the red blood cell crescent or sickle shaped. This shape does not allow the cells to move freely and sticks to the walls of vessels, causing a block that stops the flow of blood, preventing oxygen from reaching the tissues.
Since the disease is an inherited one, an allogeneic stem cell transplants from a matching sibling or a parent donor is always the recommended form of treatment.
India has emerged as one of the most popular destinations for treatment of various kinds of cancers. With new technologies emerging frequently, a large number of Indian hospitals across all major cities are now conducting stem cell/bone marrow transplants. Doctors Beyond Borders works with these hospitals and also hospitals abroad to refer patients and help them avail of best treatment methods possible. Of the various hospitals affiliated to Doctors Beyond Borders, one of them is also associated with an international agency for blood marrow and stem cell transplant to help find donors from across the globe.