What is Immunotherapy in Cancer?

Immunotherapy is a type of treatment that uses the body’s own immune system to recognize and kill cancer cells. Cancer cells often can fool the body into not recognizing they are dangerous. If the body can’t tell the difference between cancer cells and healthy cells, cancer cells may be able to “hide” from the immune system. To identify cancer cells as a threat and target them for destruction, Immunotherapy uses substances either made by the body or in a laboratory to enhance recognition or effector function of the immune response against the cancer.

Different types of Immunotherapy exist. Each works in a unique way to slow and stop the growth of cancer cells, stop cancer cells from spreading to other parts of the body and help the immune system work better overall at destroying cancer cells. Some Immunotherapy treatments boost the body’s immune system while others train the immune system to attack cancer cells

Checkpoint inhibitors are an important part of the immune system due to their ability to keep immune cells from attacking normal cells in the body. Checkpoints are proteins on immune cells that need to be turned on or off to start/stop an immune response. The immune system uses checkpoints to prevent itself from attacking normal cells in the body and deleted immune cells after their functions have been completed, for example following clearance of an infection. But melanoma cells sometimes hijack these checkpoints to avoid being attacked by the immune system. Checkpoint inhibitors target the checkpoint proteins, helping to restore the immune response against melanoma cells.

Cytokines are soluble molecules that enable immune cells to communicate with each other. Cytokines work together to make sure that the immune response is of the right strength and length of time. Laboratory-made versions of cytokines are sometimes used to boost the immune system in people with melanoma. Oncolytic viruses are viruses altered in a laboratory so that they preferentially infect and kill mainly cancer cells. Along with killing the cells directly, the viruses can also alert the immune system to attack the cancer cells. Cancer vaccines are substances that stimulate the immune system to fight infection or disease. Cancer vaccines strengthen the immune system against cancer cells.

Nonspecific immune stimulators boost the immune system in a general way to help the immune system attack cancer cells.

Certain immunotherapies work well when given alone. Others work better in combination with additional treatment strategies.

At present, the clinical use of Immunotherapy is largely restricted to the adjuvant treatment of Stage III and systemic treatment of Stage IV melanomas, although there is intense interest in evaluating Immunotherapy as neoadjuvant or adjuvant therapy for all stages.