Most types of cancer are classified by a process known as staging. Staging assigns numbered stages to cancers based on tumor size and how far the cancer spreads from the original site. Myelodysplastic syndromes (MDS), however, are not staged because they usually spread throughout the bone marrow.

Instead, the prognosis and treatment options for MDS depend on a number of factors, including:

• Whether a previous cancer treatment caused the myelodysplastic syndrome
  
  
• The amount of blast cells in the bone marrow
  
  
• Whether one or more types of blood cells are involved
  
  
• Certain changes in chromosomes
  
  
• Whether the myelodysplastic syndrome is untreated or has recurred
  
  
• Whether the disease has progressed after treatment
  
  
• The patient’s age
  
  
• The patient’s general health

One system used to predict the prognosis of MDS patients is the International Prognostic Scoring System (IPSS). The system rates three factors:

• The percentage of blasts in the bone marrow
  
  
• Whether chromosome abnormalities are present, and if so, the type of abnormality
  
  
• How low the patient’s blood counts are

Information regarding these factors is then used to give the patient a score and group the patient into a prognosis category. For the percentage of blasts, scoring values include:

Percentages of blasts above 30 percent are not represented in this scoring system because patients with a blast percentage over 30 percent have acute myeloid leukemia (AML).

Scoring values regarding chromosome abnormalities include:

In this scoring system a good finding is defined as having either:

• A normal set of 23 chromosomes.
• A set having only a partial loss of chromosomes  No. 5 or No. 20.
• The loss of the Y chromosome.

Poor is defined as having either:

• Loss of one of the No. 7 chromosomes.
• Addition of a No. 8 chromosome.
• Three or more total abnormalities.

Scoring values regarding blood counts are based on three findings:

• The number of neutrophils is less than 1,800 per microliter.
  
  
• The number of hematocrit is less than 36 percent of red blood cells in total body volume.
  
  
• The number of platelets is less than 100,000 per microliter.

Based on these findings, scoring values regarding blood count include:

The three individual score values are then combined to determine the IPSS score. The prognoses based on the IPSS scores include:

According to the American Cancer Society (ACS), the median survival times for patients with MDS include:

Another way of predicting survival times was developed by German authors. This system, which provides survival times based on the type of disease, includes:

Although this system provides a basis for predicting prognosis, additional prognostic factors (e.g., age, general health) will increase or decrease a patient’s survival time.

According to the National Cancer Institute (NCI), MDS may also be grouped for treatment based on why the disease developed. This system describes MDS as:

• De novo myelodysplastic syndromes. MDS that develop without any known cause.
  
  
• Secondary myelodysplastic syndromes. MDS that develop after treatment for a previous cancer with chemotherapy or radiation therapy, or after exposure to radiation or certain other cancer-causing chemicals (carcinogens).
  
  
• Previously treated myelodysplastic syndromes. MDS that has not improved after treatment.