Myelodysplastic syndromes

What are myelodysplastic syndromes?

Myelodysplastic syndromes (MDS) are diseases in which the bone marrow does not make enough healthy blood cells. Bone marrow is the soft, inner part of bones. Normally, it produces three kinds of blood cells:

• red blood cells, which carry oxygen
• white blood cells, which fight infection and disease
• platelets, which help prevent bleeding by causing blood to clot.

Healthy bone marrow makes immature cells called stem cells that develop into red and white blood cells and platelets.

In MDS, the bone marrow starts producing some abnormal-looking blood cells and reduces production of the right kind of blood cells. These abnormal cells either die in the bone marrow or soon after they enter the bloodstream. As a result, people with MDS don't have enough healthy blood cells and are said to have low blood cell counts. This can lead to:

• anemia, caused by not enough red blood cells
• infections, caused by not enough white blood cells (a condition known as leukopenia or neutropenia)
• bleeding and bruising, caused by not enough platelets (a condition known as thrombocytopenia).

People with MDS are more likely to develop bone marrow cancer, especially acute leukemia. That's why this condition is sometimes referred to as "pre-leukemia" or a "pre-leukemic" state.

In most cases, the cause of MDS is not known. Having had treatment for cancer with chemotherapy and radiation therapy may increase the risk. Exposure to certain chemicals has also been linked to MDS. Some people may be born with a tendency to develop MDS.

Most patients with MDS are over age 60. The disorder is slightly more common in men than women. It is also slightly more common in whites than in other racial groups.

Symptoms of myelodysplastic syndromes

Many people with MDS have no symptoms. It's often diagnosed after a person has a complete blood count (CBC) for some other reason. Most often the first sign is a low red blood cell count (anemia).

MDS can cause fatigue, fevers, weight loss, and other symptoms. However, these problems can often be signs of other blood-related illnesses. Consult your doctor if you experience

• shortness of breath
• weakness or feeling tired
• unusually pale skin
• easy bruising or bleeding
• flat, pinpoint spots under the skin caused by bleeding
• fever
• frequent infections.

The symptoms of MDS depend on which blood cell type is involved and on their levels in your blood. People with a low red cell count may look pale. They may also feel weak, tired, or short of breath. People with a reduced white blood cell count are more prone to bacterial infections and high fevers. People with a low platelet count tend to bruise and bleed easily.

Diagnosing myelodysplastic syndromes

Your doctor will ask about your symptoms, health habits, and past illnesses and treatments. Your doctor will also order tests to evaluate your blood. A laboratory will check the number, shape, and size of the blood cells.

The key diagnostic test for MDS is a bone marrow biopsy. This involves taking a small sample of bone and liquid bone marrow from the hip bone. The patient's skin is numbed, and the sample is removed with a long needle. A pathologist (a specially trained doctor) looks for abnormalities in the cells under a microscope.

Genetic tests including the identification of mutations in the genes of the blood cells are often done.

The results of blood cell counts, the appearance of blood cells under the microscope, the presence of genetic mutations, and symptoms help determine the severity and timing of treatment and prognosis.

Expected duration of myelodysplastic syndromes

Progression of MDS varies, depending on the multiple factors.

Preventing myelodysplastic syndromes

Most cases of MDS cannot be prevented. In people who need treatment for cancer, oncologists balance the need to provide the best cancer therapy while minimizing the risk of later MDS when chemotherapy or radiation are used. Exposure to certain chemicals, such as benzene, may trigger MDS. Although doctors do not know whether smoking raises the risk of MDS, it is a risk factor for acute leukemia and several other cancers.

Treating myelodysplastic syndromes

The treatment for MDS depends on your type of MDS, your blood counts, whether or not you have symptoms, your bone marrow and genetic tests, and overall health. Patients with MDS are often treated by a hematologist or oncologist, doctors who specialize in blood disorders.

Symptoms of MDS, such as fatigue and infections, can be eased with blood transfusions. During a transfusion, your doctor replaces your missing red or white blood cells or platelets with cells from another person through a vein in your arm.

Your doctor may also inject growth factors similar to naturally occurring substances made in the bone marrow. They stimulate increased production of blood cells. One growth factor stimulates the production of red blood cells. It can be combined with another growth factor that stimulates the production of white blood cells.

Depending on the type of MDS that you have, your doctor may prescribe vitamins, antibiotics to treat infections, or other drugs. Several drugs are available for the treatment of MDS.

Some patients receive chemotherapy, which kills abnormal cancer cells like those found in leukemia.

Chemotherapy drugs are usually taken by mouth or injected into a vein or muscle. The drugs harm cancer cells, but they can damage healthy ones, too. They can also cause side effects, including:

• hair loss
• nausea
• mouth sores
• fatigue.

There are ways to lessen these side effects.

People with specific genetic defects may be eligible for certain types of targeted therapies.

An aggressive treatment called a stem cell transplant offers a potential cure for some MDS patients. The chance for a cure is higher for young people and those whose disease has not begun turning into leukemia.

In this procedure, stem cells (immature blood cells) are removed from a donor's blood. The patient has high-dose chemotherapy and (often) radiation therapy. The patient then receives the donor's stem cells through a transfusion. These cells travel to the bone marrow and begin making white blood cells, platelets, and red blood cells.

You will need various tests and exams during and after your treatment for MDS. These can show how well the treatment is working, whether your condition has changed, and what side effects to expect.

When to call a professional

Call your doctor if you notice any of these symptoms:

• shortness of breath
• fatigue or weakness
• paler-than-usual skin
• bruising or easy bleeding
• small flat spots under your skin caused by bleeding
• fever
• frequent infections.

Prognosis

The outlook for people with MDS depends on its cause, the type of blood cell affected, severity of symptoms, the person's overall health, and other factors. The bone marrow's failure to produce healthy cells usually happens gradually, so MDS is not necessarily fatal. But some people die from the complications of low blood counts, such as infections and uncontrolled bleeding.