ANNOUNCER: Cancer is the name we give to diseases in which cells multiply abnormally, by not following normal cycles of growth and death.
ROMAN PEREZ-SOLER, MD: Well, in general, normal cells are disciplined and follow instructions, whereas cancer cells are rebels. They don't follow instructions, so they grow disproportionately and without following the rules.
ANNOUNCER: Usually, the "rebel" cells grow because an error is passed along in a cell's genetic instructions.
PAUL BUNN, MD: Cancers arrive when there is a mutation in a single cell. Then that cell divides and there is two and four and so on, as it keeps dividing. These cells attract blood vessels because they need oxygen and they actually invade into the blood vessels. Once they get into the blood vessels, they go to other parts of the body, and they grow in other parts of the body. That's called a metastasis.
ANNOUNCER: The reasons cancers develop are only partially understood. A tendency toward certain cancers may run in families. But damaging radiation and chemicals in the environment may play a larger role.
DAVID H. GARFIELD, MD: Most of the time, cancer is not an inherited disease. Perhaps the predisposition or the tendency to get a cancer is inherited, but what's needed is another factor, such as the environment.
ANNOUNCER: Treating cancer of white blood cells in the bone marrow, the leukemias; and cancers of lymphocytes in the lymphatic system, the lymphomas, may involve radiation, chemotherapy, newer targeted anticancer therapies or a stem cell transplant.
For some leukemias and lymphomas, treatment can lead to a cure. Treatment of cancers in other organs, the solid tumors, depends on whether, and how far, the cancer has spread, or metastasized.
PAUL BUNN, MD: We have three main modalities to treat cancer. We have surgery; that's where you surgically remove the tumor. We have radiation therapy; that's where you treat the tumor with radiation. And then we have drugs that go in the blood and will go wherever the cancer has spread to.
Surgery is used when the cancer hasn't spread anywhere. So when you look around with a CT scan or a PET scan or staging, it's only in the place where it started, such as on the breast, prostate, etc. When cancers are localized, surgery is almost always the treatment of choice.