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.
ANNOUNCER: Surgery, when it follows an early diagnosis, can often lead to cure. This is most likely with skin cancer, breast cancer, colon cancer, cervical cancer and testicular cancer. Radiation therapy can shrink tumors and, like surgery, can sometimes lead to cure.
PAUL BUNN, MD: Radiation therapy is often used as the primary therapy when the tumor is a little bit too big to remove it, but you can still encompass the tumor in the radiation field. For example, if you had lung cancer that had spread to lymph nodes in the middle of the chest, the surgeon can't remove all that, but radiation therapy can be aimed at that entire tumor.
ANNOUNCER: Chemotherapy has been used to treat cancer since the 1940s. Still very important, the drugs work by attacking many types of cells in the body. This often leads to side effects, such as nausea and hair loss.
ROMAN PEREZ-SOLER, MD: In general, we give chemotherapy to shrink a certain proportion of tumors, to prolong the life of a proportion of the patients. We very rarely can give chemotherapy to cure. So what we do with chemotherapy, we prolong the life and then the tumor-related symptoms, disappear or improve because the tumor shrinks.
ANNOUNCER: Research is leading to a growing number of new drugs to fight cancer, based on much better knowledge of how cancer grows.
ROMAN PEREZ-SOLER, MD: Well, I think that just in the last 20 years, we have developed the tools and the understanding of what cancer is all about. So now we have the tools to understand why a cell in the body will lose that ability to control itself.
ANNOUNCER: This understanding has led to drugs known as molecular targeted therapy. These medicines hone in on processes at the heart of a particular cancer's growth, usually with much milder side effects than chemotherapy.
Many doctors believe we're at the beginning of big changes in the way cancer is treated. They caution, however, that much research still lies ahead.
PAUL BUNN, MD: Now we've developed drugs that are just beginning to reach the clinic that are helping patients, and I believe are going to revolutionize cancer therapy. This revolution isn't going to take one year. It's not going to take five years. But 10 or 20 years from now, many more people are going to be cured. Many more people are going to live long, productive lives with cancer by taking pills.