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Introduction to Cancer Immunotherapy
IMMUNOTHERAPY IS ONE OF THE MOST RECENT ADVANCES IN CANCER THERAPY
Radiation, chemotherapy, and surgery are the traditional tools in the fight against cancer. Radiation was discovered in the 1800’s by Marie Curie. Chemotherapy evolved from mustard gas (World War 1), and surgery dates back to the ancient Egyptians.
These treatment modalities are all based on destroying cancer cells by burning them (irradiation), poisoning them (chemotherapy) or removing them (surgery). While they do effectively kill or remove cancer cells, the use of these treatments is limited because large numbers of healthy cells are also destroyed. This often results in extreme morbidity and/or disfigurement of the patients treated with them. In the worst cases these treatments can sometimes result in the patient’s death.
To date, there is no “magic bullet” in the treatment of cancer, and because of the complexity of cancer biology it will likely not be attainable. It is now generally agreed that the future of cancer therapy lies in the combination of therapies with different mechanisms of action.
Immunotherapy is one of the most recent approaches to cancer therapy. It is based on the fact that the immune system is the best tool humans have for fighting disease.
Immunotherapies can be used to fight cancer by either applying an external stimulus to the immune system to make it act more ‘forcefully’ or ‘smarter’, or by providing the immune system with man–made or naturally-derived tumor specific proteins made outside of the body so that the immune system can recognize the tumor as a foreign entity and destroy it.
Immunotherapy is sometimes used by itself to treat cancer, but it is most often used in combination with traditional treatments like radiation, chemotherapy, and surgery in order to enhance their effects. One of the major benefits of immunotherapy is that it is typically not as toxic as radiation, chemotherapy, and surgery. In addition, immunotherapy often offers a different mode of attack on the tumor, thereby affording both patients and doctors alike a different “weapon” in the fight against cancer.
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LIMITATION OF THE IMMUNE SYSTEM IN FIGHTING CANCER
AND THE NEED TO EMPOWER THE IMMUNE SYSTEM
In the case of cancer, the immune system often fails to effectively fight the tumor for the following reasons:
- The normal immune system is ‘blind’ to tumor cells because the tumor cells are derived from the body’s own cells. The body ‘thinks’ of the tumor as ‘self’, which creates a phenomenon also known as ‘tumor tolerance’.
- The immune system may recognize cancer cells, but the response may not be strong enough to destroy the cancer (the response is insufficient in amount, it does not occur in the right place in the body, or it does not send the right ‘warrior cells’).
- The tumor has the ability to defend itself. Cancer cells may secrete substances that keep the immune system in check.
In the case of cancer, the immune system needs an external boost from immunotherapies to be able to become more effective in fighting the cancer. |
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