What Happens
Cancer is the growth of
abnormal cells in the body. These extra cells grow together and form masses,
called tumors. In
colorectal cancer, these growths usually start as
polyps in the
large
intestine
(colon or rectum).
Colon polyps are quite common and most do not cause
problems. However, if they are not detected and removed, some of them can turn
into cancer.
Cancers in the colon or rectum usually grow very
slowly. It takes most of them years to become large enough to cause symptoms.
If the cancer is allowed to continue growing, it eventually will invade and
destroy nearby tissues and then spread farther. Colorectal cancer spreads first
to nearby
lymph nodes. From there it may spread to other parts
of the body, usually the liver. It may also spread to the lungs, ovaries and
bones.
The long-term outcome, or prognosis, for colorectal cancer
depends on how much the cancer has grown and spread. Experts talk about
prognosis in terms of "5-year survival rates." The 5-year survival rate means
the percentage of people who are still alive 5 years or longer after their
cancer was discovered. It is important to remember that these are only
averages. Everyone's case is different, and these numbers do not necessarily
show what will happen to you. The estimated 5-year survival rate for colorectal
cancer is:1
- 90% or more if cancer is found early and
treated before it has spread.
- 67% if the cancer has spread to
nearby organs and lymph nodes.
- 10% if the cancer has spread to the
liver, lungs, or bones.