Medicines prescribed by a medical oncologist that can kill cancer cells directly are called chemotherapy. Some are given in pill form, and some are given by injection. Chemotherapy can also be considered a type of systemic therapy, because medicines go through the bloodstream to the entire body.
Some treatments are designed to help your own body’s immune system fight the cancer, similar to how your body fights off infections. This is referred to as immunotherapy. Immunotherapy works by either stimulating your immune system to attack cancer cells or providing your immune system with what it needs, such as antibodies, to fight cancer.
Cancer doctors now know much more about how cancer cells function. New cancer therapies use this information to target cancer cell functions and stop them. Called targeted therapies, they can be more specific in stopping cancer cells from growing and may make other treatments work better. For example, some medicines work to prevent cancers from growing by preventing the growth of new blood vessels that would nourish the cancer.
Other targeted therapies work more directly on cancer cells by blocking the action of molecules on the surface of cancer cells called growth factors.
Some medicines called radioprotectors can help protect healthy tissue from the effects of radiation.
Any drug that can make tumor cells more sensitive to radiation is called a radiosensitizer. Combining radiation with radiosensitizers may allow doctors to kill more tumor cells. Some types of chemotherapy and some novel targeted therapies can act as radiosensitizers.
Certain cancers may be treated with radioactive drugs that spread throughout the body via the bloodstream. These treatments may be delivered by swallowing radioactive pills or receiving radioactive fluids in the vein (intravenous). This type of treatment is called systemic radiation therapy because the medicine goes to the entire body. For example, radioactive iodine (I-131) capsules are given to treat some types of thyroid cancer. Another example is the use of intravenous radioactive material to treat pain due to cancer that has spread to the bone. Radiolabeled antibodies are monoclonal antibodies with radioactive particles attached. These antibodies are designed to attach themselves directly to the cancer cell and damage it with small amounts of radiation.