20.15 : Cancer Therapies

Cancer is one of the leading causes of death in humans and is therefore considered an important health problem throughout the world.

Some of the most commonly used cancer therapies include surgery, radiotherapy, chemotherapy, immunotherapy, and hormone therapy.

Surgery is the surgical removal of a solid tumor that is contained in one area. For example, in the case of basal cell carcinoma, surgery is often used to remove the cancerous lesion and some of the surrounding healthy tissues.

However, in cases where removal of the whole tumor may cause damage to the organ or the body, surgery can be used to remove only a certain portion of the tumor. The remaining tumor cells can be treated with the help of other therapies.

Radiation therapy uses high doses of radiation to damage DNA inside the tumor cells. While tumor cells can usually tolerate minor DNA damage, they are hypersensitive to a higher amount of damage.

This means that while irradiated cancer cells can continue to divide for some time due to impaired cell cycle checkpoint responses, once they accumulate enormous DNA damage, it eventually leads to their death.

The surrounding normal cells can also be affected by the radiation, but since these normal cells have efficient DNA repair mechanisms, they are able to survive the radiation therapy.

Chemotherapy uses anti-cancer drugs to target fast-growing cells in the body. Besides killing the rapidly dividing cancer cells, such drugs also affect other fast-growing cells in the body, such as hair follicles and blood cells. This may cause short or long-term side effects in the patient undergoing chemotherapy.

In contrast to chemotherapy, immunotherapy uses cancer vaccines, immunomodulators, and monoclonal antibodies to aid the immune system in recognizing and targeting the cancer cells in the body.

Some cancers, such as prostate cancer, are fueled by hormones produced in the body. Hormone therapy is used in such cases to block the production or action of hormones and help slow down the growth of cancer cells.

The type of therapy to be administered to a patient depends on the type of cancer and its stage of advancement. Therefore, while some patients can be treated with only one type of treatment, most cases need a combination of various therapies.