Cancer is an abnormal growth of cells which are damaged and unregulated by the body's normal mechanisms. These cells divide and grow in colonies which eventually become malignant tumors. These tumors invade or grow into nearby organs and structures. Cancer cells from the tumors can break off and spread through the blood stream or the immune system (lymph nodes) to other areas; a process called metastasis.

Pronounced "korio carcinoma". Other terms in this area include gestational trophoblastic disease, GTN, GTD, invasive mole, molar pregnancy. This constellation of related diseases is based on abnormal placental development. The placenta in a genetically abnormal pregnancy becomes very abnormal and no baby develops. In a small percentage, this abnormal placenta can become cancerous and invade the muscle of the uterus or spread to other organs. All of these conditions are extremely curable with a combination of surgery and chemotherapy. (see MOLE).

New anti-cancer treatments are first evaluated in the laboratory. When a new treatment is initially tested in humans, it is referred to as a Phase I Trial. The purpose is to determine what an appropriate dose is and generally whether or not it has any specific anti-cancer activity. When an appropriate dose is determined, then the treatment is evaluated by a Phase II Trial, in which the object is to determine if the treatment has any effect against a variety of different types of cancer. If it does, then a Phase III Trial is done in which this new treatment is tested against what is currently thought to be the best standard treatment. Usually, Phase III trials are randomized, which means that the treatment you receive, new/experimental vs. standard, is determined by chance;an example would be a flip of the coin, although the techniques uses are more sophisticated and often use computers to determine who gets which treatment. This prevents any bias from influencing the outcome when the results are evaluated. All of the current major chemotherapy drugs have gone through this type of testing. Not all experimental trials involve chemotherapy; some may involved surgical procedures or radiation therapy or other diagnostic or treatment options.

A cancer is considered to have been cured if, after treatment, remains undetectable for a long period of time. In many cases 5 year survival rate is used as an equivalent to cure. This means that for most cancers, if one lives past 5 years, it is highly unlikely that the cancer will come back. This is not true for all cancers, but is a pretty good rule for gynecologic cancers.