Basics of Cancer Treatment

Hi everyone. Today I want to talk in broad terms about the way in which skin cancer and other cancers are treated. Cancers are made up of abnormal cells that grow rapidly and continue to grow indefinitely, whereas normal cells stop proliferating at a certain point. The main point of treating cancer is to rid the body of these abnormal cells. The most common ways of treating cancer is with surgery, chemotherapy, and radiation.

It makes sense that if there is a tumor growing, a good treatment would be to surgically cut out the tumor. (This explains the surgeon motto "to cut is to cure"). An assumption we make about cancer is that a tumor grows as a single mass with well defined borders. Thus, if it is completely removed with clear margins, then the cancer should be gone. The margins must be deemed pathologically "clear", meaning that the entire cancer has been removed. Of course, the tumor must be accessible to the surgeon and for this reason, skin cancer is often treated surgically because it is easy to see and then cut out the cancer. This is not always the case as many cancers in other organs are not easily accessible. For example, cutting out a brain tumor is much more complicated and difficult to reach than a cancer sitting in the top layers of the skin.

So when is surgery not a good option? If, as in the case of the tumor on the brain, the tumor cannot be easily reached, surgery should be well thought out. Another example is if the patient is not a good surgical candidate. For example, a 90 year old man in poor health may not be able to survive a surgical procedure due to the overall frailty of his body. More commonly, surgery is not an option for people because the cancer has spread to other areas and it is not possible to cut out every piece of cancer within the body. This is when the cancer has become metastatic, meaning that the cancer has broken off from its original site and has spread to distant parts of the body.

For metastatic cancer, medical chemotherapy is the mainstay of treatment. Chemotherapy encompasses a group of medicines that are, for the most part, toxic to living cells. The goal is to have this toxic agent be absorbed by the cancerous cells more quickly than the normal cells of the body. Most often this is the case, because cancerous cells are growing much more quickly and will absorb more of the toxin. It is because chemotherapy tends to kill rapidly dividing cells that cancer patients often lose their hair. The hair cells are dividing and growing rapidly and absorb the cancer medicine which is toxic and then the growing hairs fall out. Also, because chemotherapy is toxic to the body, people undergoing chemotherapy are often sick during the treatment and may be prone to infection due to the chemotherapy killing off some of their immune cells. So the ideal of medical chemotherapy is to kill the cancerous cells more quickly than the normal cells, but this is not without risk to the patient.