Experience I'm a Doctor of Medicine. Licensed/certified physician and surgeon and specialist in Medical
Oncology and Radiation therapy in Sweden, Denmark, Finland, Iceland, Norway and the European Union. Background in Radiation Therapy, Medical Oncology, Radiation Protection, Nuclear Medicine, Diagnostic Radiology, Gynecological Oncology, Clinical Pathology, Clinical Cytology,Hematology and Internal Medicine.
M.D. from the faculty of medicine, Royal Karolinska Institute, Stockholm, Sweden. Have also been an exchange student at the Hebrew University, Hadassah Medical School, Jerusalem Israel. Former medical consultant, Swedish National Board of Radiation Protection. Former Police Surgeon and Medical Examiner, Stockholm Police Department. Former Chief Medical Officer, The Royal Guards, The Royal Horse Guards and the Royal Household Brigade, Royal Swedish Army Medical Corps. Now in private practice in Stockholm, Sweden.
I also answer questions in these other categories: General History,
Military History,
Brain Tumors,
Breast Cancer,
Colon Cancer
Question Hi, i'm a medical student doing an intercalated degree in pharmacology and I need some help with my dissertation on the anti-cancer drug bevacizumab (avastin)...
I understand the basic mechanism of action of the drug. I know it is an antibody that binds to the VEGF recetors 1 and 2, which prevents angiogenesis...
So my questions:
1) How does angiogenesis occur if you block the VEGF receptors?
2) Is it actually a good drug?
Wouldn't preventing angiogenesis will cause areas of hypoxic tumours. As hypoxic areas of tumours would select cells that are more resistant to chemotherapy and radiotherapy.
3) Why is it only used for colorectal cancers (in england) - why not for other cancers? is it not effective for other cancers?
Thanks for your help,
Alex
Answer First of all, I retired from working 5 years ago after a stroke. So I do not work now and have not done so for 5 years. That means that I have never used this drug, I have NO personal experience with it at all. All I know is what I have read, so I'm in the same position as you. If that is not enough for you I strongly suggest that you direct this question of yours to another expert here WITH personal experience of this drug.
1. Tumour growth can be seen as the growth of a parasite. This growing parasite needs - due to its growth - an increased supply of oxygen and of nutrients and has also an increased need of getting rid of heat and wastes including CO2. These needs can only be taken care of by an increased blood supply both into and out of the tumour. The only way of increasing this supply is by providing new blood vessels to and from the tumour. A tumour therefore needs to be able to stimulate the growth of such new blood vessels and in fact has that ability. To be able to grow these new vessels is an ability of very great importance to the tumour! 1. The aim of the drug is to block the formation of any such new blood vessels. If the drug works properly no new such vessels should be formed. So in that case NO angiogenesis (= forming of blood vessels). (I do hope I have understood your question). 2. If it works properly - and it seems to be doing that at least to a fair extent in a number of cases - it should work by starving the tumours. Well not only are they deprived of oxygen but also of all sorts of nutrients so there is also less "fuel" to "burn". That means that there may in relative terms not really be a hypoxic state there since the lack of oxygen is balanced by a lack of "fuel" so the need of oxygen for the metabolism is also smaller, but the cancer cells are indeed STARVED! But you are right in the matter of hypoxic cancer cells. They ARE less sensitive - especially to radiation therapy since radiation & oxygen form cytotoxic free radicals that injure the cancer cells. Hypoxic cells can form less amounts of free radicals when irradiated. But again due to the reasons given above I do not think that matters much here. So indeed I think it may be a good drug. 3. It is used in both colorectal cancers and in lung cancers. Drugs like this one are tested on a number of cancers and then used where experience tells us they work best. In Britain with National Health Service there may be political & economical factors involved of which I'm not aware. But I know it has effect on both colorectal and pulmonary cancers. It is not recommended for breast cancers though. That is all I can tell you. I do hope it has been sufficient and enough!
