Secondary Cancer

If you have been treated for cancer by radiation or chemotherapy, you are aware there is a risk of developing secondary cancer and if you were not aware, let this be your wake up call. Basically, the reason for developing secondary cancer is that most of the treatments we currently have available to us for cancer work by doing DNA damage to cancer cells as well as to normal tissue. The theory is that cancer cells don't have the repair mechanisms normal cells do. Therefore, the cancer cells die and normal cells recover (for the most part). In some cases, normal cells sustain DNA damage which they do not recover from. One known form of secondary cancer is Myelodysplastic syndrome (MDS). MDS can present itself as a primary or as a secondary cancer. As a secondary cancer, it is one of the few cancers with a known cause - chemotherapy.

I have only recently become aware of MDS through an article in the Fall 2006 issue of Cure magazine. I'm including a link to the magazine in case you might like to check it out. Once you get there, click on the number 3 under the picture of the magazine cover to go to the MDS article.

http://www.curetoday.com

ALSO, in case you would like to learn a little about MDS right now, I have included an excerpt from a MDS patient handbook below. You can find this handbook at the following web site.

http://www.mds-foundation.org


"WHAT IS MDS?

MDS, or the myelodysplastic syndromes, are a group of diseases of the bone marrow. Healthy bone marrow produces immature blood cells that then develop into red blood cells, white blood cells, and platelets. When MDS affects the normal development process, progenitor cells ("blasts") fail to respond to normal control signals, resulting in a disproportionate number of these primitive cells remaining in the bone marrow. Meanwhile, levels of the circulating, mature blood cells fall. The mature blood cells, in addition to being fewer in number, may not function properly due to dysplasia (misshapening).

Failure of the bone marrow to produce normal cells is a gradual process. Because the process is gradual and because MDS is primarily a disease of the aging-most patients are over 65 years old-it is not necessarily a terminal disease. However, some patients do succumb to the direct effects of the disease through loss of the ability to fight infections and control bleeding. In addition, for roughly 30% of the patients diagnosed with MDS, these diseases will progress to acute myeloid leukemia (AML), a type of bone marrow malignancy which does not respond well to chemotherapy. So while, in total, 70 to 75% of patients diagnosed with MDS eventually succumb to the direct effects of MDS or to AML, there is a group of patients for whom the onset of MDS will not result in a shortened life span."

"WHAT CAUSES MDS?

With a few exceptions, the exact causes are unknown. Some evidence suggests that certain people are born with a tendency to develop MDS. This tendency can be thought of as a switch that is triggered by an external factor. If the external factor cannot be identified, then the disease is referred to as "primary MDS".

Radiation and chemotherapy are among the known triggers. Patients taking chemotherapy drugs for potentially curable cancers, such as Hodgkin's disease and lymphoma, are at risk of developing MDS for up to ten years following treatment. MDS triggered by chemotherapy agents, called "secondary MDS," is usually associated with multiple chromosome abnormalities in the bone marrow. This type of MDS often develops rapidly into AML.

Exposure to certain environmental chemicals can also trigger MDS. Unfortunately, it is not clear which chemicals, aside from benzene, are implicated.

There are no known food or agricultural products that cause MDS. While alcohol consumed on a daily basis may lower red blood cell and platelet counts, alcohol does not cause MDS. As for tobacco, insufficient data are available to determine if smoking increases the risk of developing MDS. It is known, however, that the risk of developing AML is 1.6 times greater for smokers than for non-smokers.

Patients and their families often worry that MDS might be contagious. There is no evidence to suggest that MDS is caused by a virus, thus MDS cannot be transmitted to loved ones. Because they are not at increased risk of developing MDS, family members do not need to have routine blood counts. In fact, it is a very rare occasion when siblings are diagnosed with MDS."