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Doctor Kevin Most
Cancer Research: Your Dollars Make a Difference
Doctor Kevin Most
Doctor Kevin Most joined us this morning to continue his series about cancer. Today he explained where your cancer research dollars are yielding significant medical results. Check out the doctor’s notes below for more info as you listen to this podcast!
Polio… Decades ago this was a terrifying word with grave repercussions for those inflicted. Now we don’t even think about it. Why? The polio vaccine was developed. This occurred between 1952 with Jonas Salk’s discovery and 1961 with Dr Sabin’s discovery to make it an oral vaccine. The last case in the United States was noted in 1979, and we declared polio eradicated in 1994.. The impact of clean water systems and a great vaccination system has allowed us to eradicate this from the US. On a worldwide vision, we are getting there , but there are still cases noted in Africa, Afghanistan and Pakistan. It is a contagious virus that can spread easily if allowed to, and for weeks from individuals infected. It was one of the most lethal childhood diseases in the 20th century.
Why is it back in the news, You won’t believe it, but it will show us the impact of our own immune system against foreign tissue.
GBM, Gliobastoma Multiforme, is unfortunately a some what common brain tumor. There are approximately 250,000 cases of GBM diagnosed every year. It is a terrible disease, if left untreated, life expectancy is a few months. With aggressive treatment, including surgery, chemo and radiation less than 5 % survive beyond 5 years. Contrast that to breast cancer with a 90% five year survival rate.
In May of 2012, Duke University started a clinical trial linking the two topics we have just discussed. The study is using a virus made up of a polio virus and a rhino virus (common cold virus). This polio virus has been genetically changed so it won’t cause the effects that a true polio virus would. The study also chose the most difficult patients to treat, those where the GBM came back after chemo and radiation therapy.
This combo virus is injected right into the middle of the GBM tumor in the brain. The virus is deposited right where the tumor is, it is not given like a vaccine. Think about that we are using a virus that used to cause millions of childhood paralysis cases to treat brain cancer. How can this be? First it is a weakened form of the polio virus. It has been modified so it cannot replicate and thus cannot cause illness. The virus works with 2 mechanisms. The first is the power of the bodies immune system to recognize the polio virus. The second is that GBM actually allow for the virus to attach to the tumor and it causes damage to the tumor cell, by attaching to the cell it causes damage to the tumor cell. The virus attaching to the tumor now allows the immune system to see this as foreign and attacks it. The larger of the 2 mechanisms, appears to be the bodies immune system fight.
We have talked in the past that the difficult thing about cancer cells is that the body does not see them as foreign or bad, they have a coating that the bodies immune system is normally not bothered by, so the bad cells continue to replicate and tumors grow. The injected virus actually removes that special coating, attach to the tumor and then the body can see it as foreign and attack it. The goal now is to figure how much of the virus is needed as they have proven that more of this is not the solution, as too much virus can cause swelling of the brain and do more damage.
This still has a lot of work to be completed, it is very promising. No one is saying this is a cure. The concept of using a virus to fight other cancers is being done as well at sites across the country. They are studying both vaccines and virus injections for many of the deadliest cancers including melanoma and pancreatic cancer.