There is no staging system for myelodysplastic syndromes. Treatment is based on whether the disease developed after the patient was exposed to factors that cause myelodysplastic syndrome or whether the disease was previously treated. Myelodysplastic syndromes are grouped for treatment as follows:

De novo myelodysplastic syndromes

De novo myelodysplastic syndromes develop without any known cause.

Secondary myelodysplastic syndromes

Secondary myelodysplastic syndromes develop after the patient was treated with chemotherapy or radiation therapy for other diseases or after being exposed to radiation or certain chemicals that are linked to the development of myelodysplastic syndromes. Secondary myelodysplastic syndromes may be harder to treat than de novo myelodysplastic syndromes.

Previously treated myelodysplastic syndromes

The myelodysplastic syndrome has been treated but has not gotten better.

Glossary Terms

Treatment with drugs that kill cancer cells.

In cancer, the first occurrence of cancer in the body.

A group of diseases in which the bone marrow does not make enough healthy blood cells. Also called preleukemia and smoldering leukemia.

Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable).

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

Performing exams and tests to learn the extent of the cancer within the body, especially whether the disease has spread from the original site to other parts of the body. It is important to know the stage of the disease in order to plan the best treatment.