To prepare your body for a bone marrow or cord blood transplant (also called a BMT), you will receive a pre-transplant treatment called a preparative regimen or a conditioning regimen.
Preparative regimen treatment
For your preparative regimen, you will receive high doses of chemotherapy and possibly radiation therapy. This high-dose treatment destroys diseased cells in your body. The treatment also destroys blood-forming cells in your bone marrow to make room for your new cells and destroys your immune system so it cannot attack your donated cells after the transplant.
The doses of chemotherapy and radiation therapy are much higher than would be used to treat the same disease in a patient who was not getting a transplant. While these higher doses may cause more severe side effects, they may also destroy more disease cells.
The preparative regimen may last four to ten days. The length and strength of this treatment depends on your disease, your age, any previous treatments you may have had and whether your disease is active. You may begin your preparative regimen even before you enter the hospital for your transplant.
All preparative regimens use chemotherapy. Some also include radiation to the whole body. This is called total body irradiation (TBI). TBI is used most often for patients with leukemia, lymphoma or myeloma. A single TBI treatment lasts from 10 to 20 minutes. TBI treatments may happen all in one day, or they may be spread out for up to 7 days, depending on the total dose you will receive.
Some patients get preparative regimens that use smaller doses of chemotherapy and less intense radiation or no radiation. A transplant using this less intense preparative regimen is called a reduced-intensity transplant. (It may also be called a non-myeloablative transplant or a mini-transplant). For details, see Reduced-Intensity Transplants
You will have your transplant of marrow or cord blood cells one or two days after completing your preparative regimen. To read about this next step of the transplant process, see Receiving Your New Cells.
Common short-term side effects
The high doses of chemotherapy and TBI used in the preparative regimen can cause short-term side effects. (Patients who receive reduced-intensity transplants may have reduced side effects.) You may have some side effects as soon as you begin your preparative regimen.
Some go away quickly after your preparative regimen stops. Others can last for a few weeks after you complete your preparative regimen and receive your transplant. Your transplant team will watch you for these side effects and treat them if they occur.
Common side effects that may begin in the first week after the preparative regimen include:
- Lack of appetite
Common side effects that may begin in the second week after the preparative regimen include:
- Mouth sores (oral mucositis)
- Lack of appetite
Some of these side effects are made worse by drugs used to prevent a common transplant complication called graft-versus-host disease (GVHD). Your doctor may give you methotrexate or other drugs for this purpose. Although these drugs may make some side effects worse, they can work well to prevent GVHD, which can be a serious complication.
If you get these or other side effects, your transplant team can treat them to make you more comfortable. If needed, your doctor may give you morphine or other medicine to control the pain of mouth sores. Mouth rinses and careful tooth and gum care can also help reduce problems with mouth sores. The mouth sores and other side effects listed above usually begin to heal when your white blood cell count rises. This will happen when your transplant engrafts (the donated cells begin to grow and create new blood cells and an immune system).
Other common short-term side effects that can be caused by the chemotherapy in the preparative regimen are tiredness, hair loss and skin rashes. The tiredness and skin rashes caused by chemotherapy will improve when your transplant engrafts. People's hair usually begins to grow back 3 to 6 months after transplant.
Less common early side effects
There are also less common side effects that can appear in the first month after the preparative regimen. Some of these can be serious. The less common early side effects include veno-occlusive disease (VOD) of the liver, lung damage and damage to the heart muscle — cardiomyopathy. Some patients may also get other uncommon side effects.
The preparative regimen can cause VOD in the first month after transplant. In VOD, small blood vessels in the liver called sinusoids swell and block the blood flow. (For this reason, VOD is now sometimes called sinusoidal obstruction syndrome.) As a result, the liver cannot remove waste products from the bloodstream. Symptoms can include pain in your upper right abdomen, weight gain and jaundice. There is no proven way to prevent it. If you get VOD, your transplant team can take steps to ease your symptoms, including:
- Giving you red blood cell transfusions
- Switching to drugs that are less harmful to the liver
- Using dialysis to reduce fluids in your body if your kidneys are also affected
- Giving you a low-salt diet
- Giving you a drug that prevents blood clots, such as heparin
The chemotherapy in the preparative regimen can damage the lungs so that it is harder to breathe. The damage can range from mild to severe. Treatment depends on the amount of damage. A patient may be given oxygen, or in severe cases may be put on a ventilator to help him or her breathe. Steroids may be effective to treat the lungs for some patients.
However, lung damage can be serious, and in some cases the damage is long-term. Your doctors may need to do tests to try to find out the cause of problems in your lungs. Infections can cause similar symptoms but may be treated differently.
Heart damage (cardiomyopathy) is a serious disease in which damage to the heart muscle makes the heart unable to work well to pump blood to your body. Cardiomyopathy is life-threatening, but it is rare.
Total parenteral nutrition
Some of side effects of the preparative regimen can make you feel less hungry or make eating hard. Some transplant patients are not able to eat and drink enough to get the nutrition, calories and fluids they need. If this happens to you, you may be given nutrients and fluids through an IV. This is called total parenteral nutrition (TPN). Patients can be given TPN until they are able to eat enough healthy foods on their own.
Long-term side effects
The treatment used in the preparative regimen is intense and can be very hard on the body. High-dose chemotherapy and radiation can sometimes cause serious long-term side effects. For more information about possible long-term side effects, see Managing Long-Term Effects of Transplant.