Cancer

Cancer is a class of diseases characterized by uncontrolled cell division and the ability of these cells to invade other tissues, either by direct growth into adjacent tissue (invasion) or by migration of cells to distant sites (metastasis). This unregulated growth is caused by damage to DNA, resulting in mutations to vital genes that control cell division, among other functions. One or more of these mutations, which can be inherited or acquired, can lead to uncontrolled cell division and tumor formation. Tumor ("swelling" in Latin) refers to any abnormal mass of tissue, but may be either malignant (cancerous) or benign (noncancerous). Only malignant tumors are capable of invading other tissues or metastasizing.

Treatment of cancer

Cancer can be treated by surgery, chemotherapy, radiation therapy, immunotherapy or other methods. The choice of therapy depends upon the location and grade of the tumor and the stage of the disease, as well as the general state of the patient (performance status). A number of experimental cancer treatments are also under development.

Related Topics:
Surgery - Chemotherapy - Radiation therapy - Immunotherapy - Stage - Performance status - Experimental cancer treatment

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Complete removal of the cancer without damage to the rest of the body is the goal of treatment. Sometimes this can be accomplished by surgery, but the propensity of cancers to invade adjacent tissue or to spread to distant sites by microscopic metastasis often limits its effectiveness. The effectiveness of chemotherapy is often limited by toxicity to other tissues in the body. Radiation can also cause damage to normal tissue.

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Because "cancer" refers to a class of diseases, it is unlikely that there will ever be a single "cure for cancer" any more than there will be a single treatment for all infectious diseases.

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Surgery

If the tumor is localized, surgery is often the preferred treatment. Example procedures include mastectomy for breast cancer and prostatectomy for prostate cancer. The goal of the surgery can be either the removal of only the tumor, or the entire organ. Since a single cancer cell can grow into a sizable tumor, removing only the tumor leads to a greater chance of recurrence. A margin of healthy tissue is often resected to make sure all cancerous tissue is removed.

Related Topics:
Surgery - Mastectomy - Prostatectomy

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In addition to removal of the primary tumor, surgery is often necessary for staging, e.g. determining the extent of the disease and whether there has been metastasis to regional lymph nodes. Staging determines the prognosis and the need for adjuvant therapy.

Related Topics:
Metastasis - Lymph node

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Occasionally, surgery is necessary to control symptoms, such as spinal cord compression or bowel obstruction. This is referred to as palliative treatment.

Related Topics:
Spinal cord compression - Bowel obstruction - Palliative treatment

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Chemotherapy

Chemotherapy is the treatment of cancer with drugs ("anticancer drugs") that can destroy cancer cells. It interferes with cell division in various possible ways, e.g. with the duplication of DNA or the separation of newly formed chromosomes. Most forms of chemotherapy target all rapidly dividing cells and are not specific for cancer cells. Hence, chemotherapy has the potential to harm healthy tissue, especially those tissues that have a high replacement rate (e.g. intestinal lining). These cells usually repair themselves after chemotherapy.

Related Topics:
Chemotherapy - Drugs - DNA - Chromosome

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Because some drugs work better together than alone, two or more drugs are often given at the same time. This is called "combination chemotherapy"; most chemotherapy regimens are given in a combination.

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A novel technique involves taking samples of the patient's tissue before chemotherapy. These tissues samples are screened to ensure they do not contain cancerous cells. The samples are expanded using tissue engineering techniques, and are then re-implanted following high dose chemotherapy in order to recolonise the damaged and somewhat destroyed tissue. A variation upon this method uses allogenic samples (samples donated by a different donor) instead of the patient's own tissue{{fn|4}}.

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Immunotherapy

Immunotherapy is the use of immune mechanisms against tumors. These are used in various forms of cancer, such as breast cancer (trastuzumab/Herceptin®) but also in leukemia (gemtuzumab ozogamicin/Mylotarg®). The agents are monoclonal antibodies directed against proteins that are characteristic to the cells of the cancer in question, or cytokines that modulate the immune system's response.

Related Topics:
Immunotherapy - Immune - Breast cancer - Trastuzumab - Leukemia - Gemtuzumab ozogamicin - Monoclonal antibodies - Cytokine

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Radiation therapy

Radiation therapy (also called radiotherapy, X-ray therapy, or irradiation) is the use of a certain type of energy (called ionizing radiation) to kill cancer cells and shrink tumors. Radiation therapy injures or destroys cells in the area being treated (the "target tissue") by damaging their genetic material, making it impossible for these cells to continue to grow and divide. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue.

Related Topics:
Radiation therapy - Ionizing radiation

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Radiation therapy may be used to treat almost every type of solid tumor, including cancers of the brain, breast, cervix, larynx, lung, pancreas, prostate, skin, spine, stomach, uterus, or soft tissue sarcomas. Radiation can also be used to treat leukemia and lymphoma (cancers of the blood-forming cells and lymphatic system, respectively). Radiation dose to each site depends on a number of factors, including the type of cancer and whether there are tissues and organs nearby that may be damaged by radiation.

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Hormonal suppression

The growth of nearly all tissues, including cancers, can be accelerated or inhibited by providing or blocking certain hormones. This allows an additional method of treatment for many cancers. Common examples of hormone-sensitive tumors include certain types of breast, prostate, and thyroid cancers. Removing or blocking estrogen, testosterone, or TSH, respectively, is often an important additional treatment.

Related Topics:
Thyroid cancer - Estrogen - Testosterone - TSH

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Treatment trials

Clinical trials, also called research studies, test new treatments in people with cancer. The goal of this research is to find better ways to treat cancer and help cancer patients. Clinical trials test many types of treatment such as new drugs, new approaches to surgery or radiation therapy, new combinations of treatments, or new methods such as gene therapy.

Related Topics:
Clinical trial - Gene therapy

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A clinical trial is one of the final stages of a long and careful cancer research process. The search for new treatments begins in the laboratory, where scientists first develop and test new ideas. If an approach seems promising, the next step may be testing a treatment in animals to see how it affects cancer in a living being and whether it has harmful effects. Of course, treatments that work well in the lab or in animals do not always work well in people. Studies are done with cancer patients to find out whether promising treatments are safe and effective.

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Patients who take part may be helped personally by the treatment(s) they receive. They get up-to-date care from cancer experts, and they receive either a new treatment being tested or the best available standard treatment for their cancer. Of course, there is no guarantee that a new treatment being tested or a standard treatment will produce good results. New treatments also may have unknown risks, but if a new treatment proves effective or more effective than standard treatment, study patients who receive it may be among the first to benefit.

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Complementary and alternative medicine

Complementary and alternative medicine (CAM) treatments are the diverse group of medical and health care systems, practices, and products that are not presently considered to be effective by the standards of conventional medicine. Some non-conventional treatment methods are used to "complement" conventional treatment, to provide comfort or lift the spirits of the patient, while others are offered as alternatives to be used instead of conventional treatments in hope of curing the cancer.

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Common complementary measures include prayer or psychological approaches such as "imaging." Many people feel these approaches benefit them, but most have not been scientifically proven and therefore face skepticism. Other complementary approaches include traditional medicine like Traditional Chinese Medicine.

Related Topics:
Prayer - Traditional Chinese Medicine

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A wide range of alternative treatments have been offered for cancer over the last century. The appeal of alternative cures arises from the daunting risks, costs, or potential side effects of many conventional treatments, or in the limited prospect for cure. Proponents of these therapies are unable or unwilling to demonstrate effectiveness by conventional criteria. Alternative treatments have included special diets or dietary supplements (e.g., the "grape diet" or megavitamin therapy), electrical devices (e.g., "zappers"), specially formulated compounds (e.g., laetrile), unconventional use of conventional drugs (e.g., insulin), purges or enemas, or physical manipulations of the body. Some of these treatments meet all the criteria for fraud or magic. Collectively they are referred to by skeptics as cancer quackery. An extensive, explanatory catalog of these treatments is available at Quackwatch http://www.quackwatch.org/00AboutQuackwatch/altseek.html. Almost all physicians recommend against using these modalities as sole treatment for potentially fatal conditions such as cancer.

Related Topics:
Laetrile - Fraud - Magic - Cancer quackery - Quackwatch

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