In medicine, an adjuvant is a substance, usually a drug, which is able to modify the efficacy of other drugs. In vaccines, for example, adjuvants are added to the vaccine preparation to enhance the protective immune response generated by the recipient. In cancer treatment, an adjuvant therapy is used in combination with other treatments to help destroy cancer cells.
Whenever possible, surgery is used as the primary treatment for cancer. Surgery is generally the most effective way to remove tumors while minimizing harmful side effects for patients. In some cases, however, surgery alone is not enough to prevent cancer returning. If cancer has metastasized, for example, it is likely that cancer cells are present in other parts of the body. In such cases an adjuvant therapy is needed to kill any cancer cells which surgery could not remove.
There are several different types of cancer adjuvant therapy, including chemotherapy, radiation therapy, hormone therapy, and immunotherapy. Some of these treatments are specifically targeted to certain types of cancer, while others are more general. Another type of therapy, called targeted therapy, is specifically used to treat just one or two types of cancer.
Chemotherapy is the most commonly used type of adjuvant therapy for cancer. This therapy uses drugs which specifically kill cells which are multiplying rapidly. Cancer cells are vulnerable to these drugs, however immune cells are hair follicles are also vulnerable. This is why side-effects of some types of chemotherapy include hair loss and increased susceptibility to infection.
Radiation is an adjuvant therapy which is also sometimes used as a primary cancer treatment. This type of therapy kills cancer cells by exposing them to ionizing radiation, like that which is used to generate x-rays. Radiation therapy is very focused, and does not affect the entire body the way chemotherapy does. Radiation beams are directed only to the part of the body affected by cancer.
Hormone therapy is used to treat cancers such as breast, uterine, ovarian, or prostate cancer, all of which are sensitive to certain types of hormones. People receiving this therapy are given medication which reduces the amount of hormones they produce, which causes cancer cells to die. Possible side effects include decreased sex drive, hot flashes, and a risk of heart problems.
Immunotherapy is an experimental treatment which attempts to induce a protective immune response to cancer cells. Some types of cancer, such as lymphoma and melanoma, have been successfully treated with immunotherapy. Another new treatment, called targeted therapy, is used for specific types of cancers only. In the case of breast cancer, for example, the therapy is targeted towards correcting a genetic mutation that causes over-production of a protein called HER2. The therapy reduces production of the protein and slows down the growth of the cancer.