Chemotherapy Health Article

Definition

Chemotherapy is the treatment of cancer with anti- cancer drugs.

Purpose

The purpose of chemotherapy is to kill cancer cells. Not only is it often used to treat patients with cancer that has metastasized (spread) from the site in the body where it originated, today chemotherapy can be used to prevent metastasis as well. Chemotherapy destroys cancer cells throughout the body, killing cells that have broken off from the main tumor and traveled through the blood or lymph systems to other parts of the body.

Chemotherapy can cure some types of cancer. In some cases, it is used to slow the growth of cancer cells or to keep the cancer from spreading to other parts of the body. When a cancer has been removed by surgery, chemotherapy may be used to keep the cancer from recurring; this is known as adjuvant therapy. Chemotherapy also can ease the symptoms of cancer, helping some patients to have a better quality of life.

Precautions

There are many different types of chemotherapy drugs. Oncologists (specialists in cancer) determine which drugs are best suited for each patient. This decision is based on the type of cancer, the patient's age, health, and preferences, as well as other drugs the patient is taking. Some patients may not tolerate certain chemotherapy drugs if they have other illnesses such as heart disease, kidney disease, or diabetes.

Chemotherapy, whether administered in the hospital, clinic, or at home, is prepared by the pharmacist. The pharmacy and pharmacy assistants provide and reinforce patient education about common as well as infrequent side effects of chemotherapy. When administered in the hospital, clinic, physician's office, or other treatment setting, it is usually administered by a specially trained nurse, mid-level practitioner (physician assistant of nurse practitioner), or physician.

Description

More than 50 chemotherapy drugs are currently available to treat cancer, and many more are being tested for their ability to destroy cancer cells. Most chemotherapy drugs interfere with the ability of cells to grow or multiply. Although these drugs affect all cells in the body, most useful treatments are more effective against rapidly growing cancer cells. Since chemotherapy affects rapidly growing cells, it often affects cells that normally grow rapidly such as cells in the bone marrow, stomach intestines, and hair follicles. This is why some of the most common side effects of chemotherapy are bone marrow suppression, nausea, vomiting, and hair loss.

Types of chemotherapy drugs

Chemotherapy drugs are classified based on their mechanisms of action (how they work). The main types of chemotherapy drugs are:

• Alkylating drugs kill cancer cells by directly attacking DNA, the genetic material of the genes. Cyclophosphamide is an example of an alkylating drug.
• Antimetabolites interfere with the production of DNA thereby preventing cells from growing and multiplying. An example of an antimetabolite is 5-fluorouracil (5-FU).
• Antitumor antibiotics are made from natural substances such as fungi in the soil. They interfere with important cell functions, including production of DNA and cell proteins. Doxorubicin and bleomycin belong to this group of chemotherapy drugs.
• Plant alkaloids prevent cells from dividing normally. Vinblastine and vincristine are plant alkaloids obtained from the periwinkle plant.
• Steroid hormones slow the growth of some cancers that depend on hormones. For example, tamoxifen is used to treat breast cancers that depend on the hormone estrogen for growth.

Combination chemotherapy

The oncologist decides which chemotherapy drug or combination of drugs will work best for each patient. The use of two or more drugs together often works better than a single drug alone. This is called combination chemotherapy. Scientific studies and clinical research trials of different drug combinations help determine which combinations are most effective for each type of cancer.