COLORECTAL CANCER - All Sections
What Is Cancer?
Cancer develops when cells in a part of the body begin to grow out of control. Although there are many kinds of cancer,
they all start because of out-of-control growth of abnormal cells.
Normal body cells grow, divide, and die in an orderly fashion. During the early years of a person's life, normal cells divide
more rapidly until the person becomes an adult. After that, cells in most parts of the body divide only to replace worn-out or
dying cells and to repair injuries.
Because cancer cells continue to grow and divide, they are different from normal cells. Instead of dying, they outlive normal
cells and continue to form new abnormal cells.
Cancer cells can sometimes travel to other parts of the body where they begin to grow and replace normal tissue. This
process, called metastasis, occurs as the cancer cells get into the bloodstream or lymph vessels of our body. When cells from
a cancer like colorectal cancer spread to another organ like the liver, the cancer is still called colorectal cancer, not liver
Cancer cells develop because of damage to DNA. This substance is in every cell and directs all its activities. Most of the
time when DNA becomes damaged the body is able to repair it. In cancer cells, the damaged DNA is not repaired. People
can inherit damaged DNA, which accounts for inherited cancers. More often, though, a person's DNA becomes damaged by
exposure to something in the environment, like smoking.
Cancer usually forms as a tumor. Some cancers, like leukemia, do not form tumors. Instead, these cancer cells involve the
blood and blood-forming organs and circulate through other tissues where they grow.
Remember that not all tumors are cancerous. Benign (noncancerous) tumors do not spread to other parts of the body
(metastasize) and, with rare exceptions, are not life threatening.
Different types of cancer can behave very differently. for example, lung cancer and breast cancer are very different diseases.
They grow at different rates and respond to different treatments. That is why people with cancer need treatment that is aimed
at their particular kind of cancer.
Cancer is the second leading cause of death in the United States. Half of all men and one-third of all women in the US will
develop cancer during their lifetimes. Today, millions of people are living with cancer or have had cancer. The risk of
developing most types of cancer can be reduced by changes in a person's lifestyle -- for example, by quitting smoking and
eating a better diet. The sooner a cancer is found and treatment begins, the better are the chances for living for many years.
file:///c|/temp/catalog/INDEX.HTM (1 of 34) [6/17/2004 4:58:52 PM]