Myelodysplastic Syndromes
Myelodysplastic syndromes or MDS are a group of conditions caused by abnormal blood-forming cells of the bone marrow. The word myelo refers to bone marrow and dysplastic to abnormal growth. In MDS, the bone marrow cannot make the right kind of blood cells. These abnormal blood cells die before they leave the bone marrow or shortly after getting into the bloodstream. As a result, people with MDS have too few healthy blood cells. Their blood cell counts are said to be low.
Risk Factors:
Smoking may be a risk factor for MDS. Many people know that smoking causes cancers of the lungs, mouth, and throat, but few also know that it can affect cells that do not come into direct contact with smoke. Substances in tobacco smoke that cause cancer get into the bloodstream and can affect many parts of the body. For example, smoking is a known risk factor for acute myeloid leukemia.
Age is a risk factor for MDS. Most patients are elderly. MDS is also slightly more common in men than in women.
Inherited diseases have been linked to MDS because MDS seems to occur more often in some families. A rare type of anemia (shortage of certain blood cells) called Fanconi anemia greatly increases the risk of leukemia or MDS.
Radiation and certain chemicals have also been linked to MDS. But the most important risk factor for MDS is earlier treatment for cancer. Patients with some cancers are treated with drugs (chemotherapy or chemo) that can make the person more likely to develop MDS. Combining these drugs with radiation therapy increases the risk further. Doctors are also seeing cases of MDS in patients who have had stem cell transplants (bone marrow transplants) because these patients receive very high doses of chemo. But the benefits of treating life-threatening cancers must be balanced against the small chance of having MDS later.
Signs and Symptoms:
MDS can cause many signs and symptoms such as weight loss, fever, and loss of appetite.
Shortages of one or more types of blood cells can cause most of the symptoms of MDS.
- A shortage of red blood cells can cause tiredness, shortness of breath and pale skin.
- A shortage of normal white blood cells can lead to infections and high fevers.
- A shortage of platelets can cause easy bruising and bleeding.
Detection:
Blood cell tests: Patients with MDS will often have changes in the number of different blood cell types. Under the microscope the cells may also look different in shape and size.
Bone marrow biopsy: For a biopsy, a small sample of bone and bone marrow are removed. The skin is first numbed and then a needle is used to remove the sample from the back of the hip (pelvic) bone.
Treatment:
Chemotherapy
Chemotherapy (most often called "chemo") is the use of drugs, taken by mouth or injected into a vein, to treat cancer.
While chemo drugs kill cancer cells, they can also damage normal cells, causing side effects. These side effects depend on the type of drugs given, the dose, and how long they are given.
Temporary side effects can include:
- hair loss (the hair grows back once treatment ends)
- mouth sores
- loss of appetite
- nausea
- vomiting
- greater chance of infection (from a shortage of white blood cells)
- easy bruising and bleeding (from low platelet counts)
- fatigue (from a shortage of red blood cells)
Growth Factors
Growth factors are substances that speed up the making of blood cells in the bone marrow. The body itself makes growth factors, but scientists have also learned how to make them in the lab. They can then be given to patients to help their bodies make more blood cells.
Stem Cell Transplant
In a stem cell transplant (SCT) the patient’s bone marrow is destroyed on purpose using high doses of chemo and radiation. Once the abnormal bone marrow cells are destroyed, they are replaced with new, disease-free blood-forming stem cells. For patients with MDS or MPD, these new stem cells come from a donor—often a brother or sister. If there is no matching family member to be a donor, then a matched, unrelated donor is used.
Side effects: the side effects of SCT can be divided into early and long-term effects. Early on, the side effects are the same as those caused by high-dose chemo. Those side effects that occur later can last for a long time. They include:
- radiation damage to the lungs (this is rare)
- graft vs. host disease: this can happen when the donor’s immune system cells attack the patient’s tissues. Symptoms include weakness, tiredness, dry mouth, rashes, infection, and muscle aches.
- damage to the ovaries that can result in infertility, sudden change of life (menopause), and hot flashes
- damage to the thyroid gland
- cataracts (clouding of the eye that can cause vision problems)
The following book is available from the American Cancer Society. Call us at 1-800-ACS-2345 to ask about costs or to place your order.
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