Chemotherapy refers to a drug treatment for cancer. These anti-cancer drugs are known as cytotoxic drugs. In this article we will give general information on chemotherapy.
Cytotoxic Drugs Overview
A cytotoxic drug is a drug that has toxic effect on cancerous cells. Cytotoxic drugs work by killing cancer cells and preventing them from dividing abnormally. There are different cytotoxic drugs that act differently on the cells. However, their common feature is to interfere with growth of cancer cells. Some cytotoxic drugs act by directly affecting genetic material of cancer cell and others prevent the cells from taking nutrients required for their reproduction.
A course of chemotherapy most commonly involves usage of two or more cytotoxic drugs. Each drug used in chemotherapy has different action thus increasing the chance of successful treatment.
There is a variety of cytotoxic drugs that are used for treatment of cancer. Type of cytotoxic drug used is determined by the form and stage of cancer that has to be treated.
Cancer and normal cells
Cytotoxic drugs are the most effective for types of cancer characterized by rapid growth of the cancer cells. Majority of healthy cells like muscle cells, heart cells, brain cell and bone cells do not multiply and divide frequently. Thus, they are not significantly affected by cytotoxic drugs.
However, there are some body cells that quickly divide and multiply. This includes hair cells, bone marrow cells and cells lining the mouth, stomach and intestines. Side effects of chemotherapy occur because cytotoxic drugs affect these cells. But, unlike cancer cells, normal cells are able to recover more quickly after the treatment has ended.
Purpose of Chemotherapy
Chemotherapy is a treatment approach designed to cure cancer. It may be used alone or in combination with other cancer treatments. It can be administered in addition to surgical treatment to remove a tumor in order to prevent spreading of cancer cells. If chemotherapy is used after a main treatment it is called adjuvant chemotherapy. On the other hand, when chemotherapy is given prior to surgery it is known as neoadjuvant chemotherapy.
Chemotherapy can be also given to relieve symptoms of cancer. This is known as palliative chemotherapy. In such case, cytotoxic drugs are used despite the poor outlook in order to reduce the pain and pressure symptoms cased by a tumor.
Delivery of Cytotoxic Drugs
Cytotoxic drugs are most commonly delivered intravenously. Some chemotherapeutic agents can be given orally in the form of liquids or tablets. In case of brain or spinal cord cancer, cytotoxic drugs can be administered through injection directly into the fluid surrounding the brain and spinal cord. This is done in a procedure known as lumbar puncture. Additionally, chemotherapy can be given by injecting a drug into a muscle, the chest cavity or directly into a tumor. Cytotoxic drugs may be also applied topically.