What causes MDS?

Most experts agree that MDS should be considered a cancer of the blood and bone marrow. Often times, doctors don't know the exact cause of MDS. These cases are called de novo MDS. We do know that certain lifestyle factors are linked to MDS.  MDS cannot be passed down through the genes from parent to child and it cannot be passed through germs from person to person.

You are more likely to develop MDS if you have:

  • Been a smoker
  • Been heavily exposed to certain chemicals, such as benzene
  • Had chemotherapy or radiation treatments. These can cause treatment-related or secondary MDS. Treatment-related MDS is often severe and can be more difficult to treat than de novo MDS. Approximately 90% of people with myelodysplastic syndrome have what is called, “de novo” MDS, meaning it arises without any known cause. A minority of people with MDS have a bone marrow condition that came about as a result of therapies for other cancers – what we call therapy-related MDS, or t-MDS. This is the type of MDS that occurred in Robin Roberts, the co-anchor of ABC television’s Good Morning America.

    t-MDS arises, on average, 5-7 years following treatment for other cancers. This is an average, though, and t-MDS can occur 1 year following other therapy or even decades after cancer treatment. Both prior chemotherapy or prior radiation therapy can lead to MDS.

    Cancer patients at higher risk for developing MDS as a result of their cancer treatment include (but are certainly not limited to) women treated for breast cancer, people treated for blood or bone marrow disorders such as lymphoma, multiple myeloma, or chronic lymphocytic leukemia, head and neck cancers, Gastrointestinal cancers, lung cancers, and possibly men treated for prostate cancer.

    It is important to recognize that, while t-MDS represents approximately 10% of MDS cases, the chance of developing MDS if you are treated for another cancer is very low - less than 1/2 of 1% (0.5%) in most cases, though the risk increases in patients who receive multiple rounds of chemotherapy and radiation therapy, and also in those who undergo stem cell transplants for conditions like lymphoma.

    Treatment for t-MDS is the same as for de novo MDS, and preliminary studies indicate that patients with t-MDS do just as well with these therapies as do patients with de novo MDS.

    While many consider patients who have t-MDS to have a worse prognosis than those with de novo MDS, this is highly controversial. Certainly, patients treated with chemotherapy for other cancers, who then develop MDS, appear to have a worse risk of chromosome abnormalities than those treated with radiation therapy for other cancers, or those with de novo MDS.  If you have been treated for another type of cancer, you may want to consult with a hematologist or oncologist if you have new or persistent low blood counts.