Chemotherapy involves the use of toxic drugs to kill quickly dividing cells in the body. Although there are many families of chemo drugs, each with its distinct action within the cell, chemo drugs typically damage proliferating cells or interfere with essential cellular pathways. This interference prevents the cell from generating the chemicals needed to sustain life, while damage to the cell can directly lead to cell death. Chemotherapy drugs have a number of medical applications, and are used to treat a number of diseases.
Cancer Treatment
Perhaps the most well-known use for chemotherapy is as part of a cancer treatment strategy. Chemotherapy drugs target rapidly dividing cells in the body, which includes cancer cells. They can effectively treat early-stage tumors, as well as later-stage advanced metastatic cancers. Doctors may recommend chemotherapy to treat solid tumors, such as breast cancer or lung cancer; as well as blood-related tumors like leukemia. During cancer treatment, patients undergoing chemotherapy may develop a number of side effects. Medline Plus indicates that the most common side effects of chemotherapy for cancer treatment are nausea, vomiting, hair loss and fatigue. These side effects occur during a course of chemotherapy and improve after completion of treatment.
Treating Autoimmune Disorders
In some cases, chemotherapy drugs can treat autoimmune disorders, such as rheumatoid arthritis, according to Northwestern University. There are a number of automimmune disorders, characterized by a chronic overactivation of the immune system. As a result, patients with autoimmune disorders suffer from excessive inflammation and pain, which, if severe, can be very debilitating. At their heart, autoimmune disorders are often growth disorders: the release of inflammatory factors promotes cell growth and further stimulates the immune system, leading to the release of even more inflammatory factors. Chemotherapy works by killing excess immune system cells to lower the levels of inflammation in the body. Patients receiving chemotherapy for autoimmune disorders must undergo medical testing to ensure their immune cell count does not become too low, since too few immune cells leaves a patient open to infection.
Preventing Transplant Complications
Chemotherapy drugs can also facilitate organ and tissue transplants by preventing complications with tissue transplants. Following a tissue transplant, the immune system can recognize the transplanted organ as foreign, due to the presence of factors on the surface of the foreign cells. Once the immune system recognizes a foreign object in the body, the immune system begins to attack the tissue, causing tissue damage and inflammation. In the presence of foreign objects the body also increases the number of immune cells to help fight a perceived infection, causing post-transplantation lymphoproliferative disease. Doctors can use chemotherapy before or after transplant to suppress the immune system and prevent immune cells from attacking the transplanted tissue. A report in the "Nature Reviews Clinical Oncology" journal published in 2010 highlights the use of the drug rituximab in decreasing the risk of immune-related disorders and rejection after organ transplant, improving patient survival.
