cancer:
Treatment
Developments in the treatment of cancer have led to greatly improved survival and quality of life for cancer patients in the past three decades. Traditionally, cancer has been treated by surgery, chemotherapy, and radiation therapy. In recent years immunotherapy has been added to that list. New drugs and techniques are constantly being researched and developed, such as antiangiogenic agents (e.g., angiostatin and endostatin), genetically engineeredmonoclonal antibodies, retinoid agents, and therapeutic vaccines (agents that stimulate the immune system to attack cancerous cells).
For most kinds of cancer, surgery remains the primary treatment. It is most effective if the cancer is caught while still localized. Some cancers that spread to the lymph system are sometimes treated by extensive surgical removal of tissue, but the trend is toward more conservative procedures (seemastectomy). Cryosurgery, the use of extreme cold, and electrodessication, the use of extreme heat, are also being used to kill cancerous tissue and the surrounding blood supply. If the cancer has metastasized, surgery is often replaced by or followed by radiation therapy (which is a localized therapy) and chemotherapy (which is a system-wide therapy).
For some cancers, radiation therapy—either from an external beam or from implanted radioactive pellets—is the primary treatment. The usual forms are X rays and gamma rays. Use of radioactive elements specific for particular target organs, such as radioactive iodine specific for the thyroid gland, is effective in treating malignancies of those organs.
Cytotoxic chemotherapy is used as a primary treatment for some cancers, such as lymphomas and leukemias or as an addition to surgery or radiation therapy. Cytotoxic drugs (drugs that are toxic to cells) are aimed at rapidly proliferating cells and interfere with nucleic acid and protein synthesis in the cancer cell, but they are often toxic to normal rapidly proliferating cells, such as bone marrow and hair cells. Often a combination of cytotoxic drugs is used. Drugs that reduce side effects may be added to the treatment, such as antinausea agents.
Hormonal chemotherapy is based upon the fact that the growth of some malignant tumors (specifically those of the reproductive organs) is influenced by reproductive hormones.Tamoxifenis a naturally occurring estrogen inhibitor used to prevent breast cancer recurrences. Flutamide is sometimes used in prostate cancer to inhibit androgen uptake. Sex-hormone related drugs such asDESand tamoxifen, which may be carcinogenic under some conditions, have proven to be protective under others.
Sections in this article:
- Introduction
- Causes of Cancer
- Cancer Susceptibility
- Tumor Development
- Symptoms
- Prevention and Detection
- Treatment
- Bibliography
The Columbia Electronic Encyclopedia,6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
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