Chemotherapy regimens are aimed at destroying rapidly growing cancer cells with cytotoxic substances. Such a regimen may be used to try and cure a patient or to provide palliative relief and ease symptoms in the advanced stages of cancer. While curative chemotherapy aims to increase survival outcomes, palliative chemotherapy provides symptomatic relief for terminal cancer patients.
Normally, chemotherapy is administered in cycles of treatment. Patients are infused with drugs during regular weekly or bi-weekly sessions under close supervision at the hospital. After a certain amount of sessions have been completed, treatment is stopped for several weeks to allow the patient to rest and their body to recuperate from the cytotoxic effects of chemotherapy. Most cancers require six or more of these chemotherapy cycles and often involve a combination of chemotherapy agents.
The cytotoxic agents used in chemotherapy are not specific to cancer cells alone and also target healthy cells that divide rapidly under normal circumstances, such as those in the bone marrow, digestive tract and hair follicles.
Destruction of the bone marrow cells that would normally give rise to red blood cells, white blood cells and platelets can lead to anemia, infection and a tendency to bleed easily. Destruction of cells in the digestive tract can lead to nausea, vomiting, mucosal inflammation and diarrhea, while damage to the hair follicles can cause a patient to lose their hair.
Combination chemotherapy is a term used to describe chemotherapy that is accompanied by other therapies such as radiotherapy, surgery or other anti-cancer drugs. Each treatment has a different mechanism of action for interrupting the division and proliferation of rapidly dividing cells. The treatments also cause different sets of side effects.
Neoadjuvant chemotherapy is the term used to describe the initial chemotherapy that is given prior to surgery in order to shrink tumors to a size small enough to be operated on. Adjuvant chemotherapy refers to the treatment that is given after surgical removal of the bulk of a tumor.