Acute Myeloid Leukaemia (AML) is a type of blood cancer that originates in the bone marrow, where the blood cells grow abnormally and develop into immature cells called blast cells that build up in the bone marrow and leave no room for other normal blood cells. The primary treatment that is suggested for most types of AML is chemotherapy, which is usually combined with targeted drugs for better effect. Doctors offer stem cell therapy if these combined therapies are ineffective in treating AML. Stem cell therapy is a powerful treatment that involves replacing the cancerous cells in the bone marrow with stem cells which are immature blood cells that will grow into healthy ones instead of abnormal cells.
While stem cell therapy seems like a foolproof way to treat cancer, it is not suitable for everyone since the process in itself takes several months and may have risks or side effects.
Types of stem cell transplants
Stem cells are spongy cells found in the bone marrow that grow into the different types of blood cells that a person’s body needs. A stem cell transplant helps in replacing the cells in the bone marrow which have been damaged by cancer or chemotherapy and radiation. In stem cell transplant, the doctor injects stem cells into the patient’s bloodstream, which travel to the bone marrow and helps rebuild the patient’s immune system and increase the body’s defence against the disease since it had been previously weakened by chemotherapy.
There are two main types of stem cell therapy, autologous and allogeneic.
Autologous stem cell transplant
In this type of transplant, the doctor will collect stem cells from the patient’s body before they begin cancer treatment and put them back in the body once the cancer cells in the body have been killed by chemotherapy. The advantage to this method of transplant is that there are lower chances of the serious side effect called “graft-versus-host disease”, where the newly reintroduced stem cells are considered a foreign body and killed by the healthy cells. The downside to this treatment is that the new stem cells won’t consider the leftover cancer cells dangerous. It is also possible that a few cancer cells are collected along with the stem cells and are reintroduced into the body after treatment.
Allogeneic stem cell transplant
This kind of transplant uses stem cells from another person. Doctors find a person whose stem cells are similar to yours so that your body doesn’t see it as a threat. Usually, donors who are siblings are the closest match to the patient, and if there aren’t any relatives who can donate their stem cells, then an anonymous donor is found. The pros to this method are that the newly introduced stem cells may recognise the cancer cells as foreign bodies and kill them since they are not from the patient’s body. Another advantage is that the patient can get more stem cells down the line if required. The cons present in this method are that there are chances your body will destroy the stem cells before they have a chance of reaching the bone marrow and multiplying. There is also a chance that the donor stem cells bring an infection with them from the donor, and since the patient’s immune system is already weak, the chances of infection are higher. Another possibility is that the donor cells may attack parts of the patient’s body since it is not from the patient and cause “graft-versus-host disease”.
Process of stem cell transplant
The first step in beginning the process of transplant is conditioning, where the patient undergoes chemotherapy or radiation. During this stage, there are three things that the doctors focus on
- Killing the cancer cells
- Making room in the bone marrow for the transplanted cells
- Weakening the patient’s immune system so that it is less likely to attack the new cells.
The high dosage of chemo given during conditioning is an intense part of the treatment, and the patient may experience side effects like hair loss, nausea and breathing trouble. All these side effects will be treated by the doctors who will suggest medicines to ease the concerns.
On the day of the infusion, the doctors will introduce the stem cells into the body through a painless process where they insert a thin tube in the vein in the chest.
There are side effects that occur after infusion, such as fever and chills, low blood pressure, cough, chest tightness or pain; however, they are temporary and will settle down soon.
Care after the transplant
It will take several weeks for the stem cells to start making new blood cells in the patient’s body, and they will be under the constant monitoring of the doctor until they become routine. While the successful completion of the transplant is a huge milestone for the patient, there are still a few risk factors that need to be checked until the stem cells start producing blood cells.
The minor physical problems that the patient needs to be careful about are infections which the patient is more prone to since their immune system is weak. The doctors will prescribe antibiotics and antiviral tablets for the patient during this time. The patients are also more inclined to bruising and bleeding since the platelets that are responsible for blood clotting are destroyed during the conditioning treatment. A person is also more susceptible to lung infections such as pneumonia, and the medical team will be monitoring them to treat them immediately.
Graft-versus-host disease is another crucial risk factor where the transplanted stem cells attack the host patient’s body cells. This disease is more common in the allogeneic method of transplant, and the effects of this disease can be treated with steroids.
While stem cell transplants are complex procedures with significant risks, the proper combination of care taken before, during and after the transplant and a wholesome approach to the process will benefit the patient and their family immensely.