Colorectal Cancer - What Happens
How cancer grows and spreads
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). If colon polyps aren't found and removed, they may 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 grow, over time it 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, and less often, to other organs in the body.
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." This means the percentage of people who are still alive 5 years or longer after their cancer was found. It is important to remember that these are only averages. Everyone's case is different. And these numbers don't 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. This means that 90 or more out of 100 people will still be alive in 5 years if the cancer is found early and treated before it has spread.
- 69% if the cancer has spread to nearby organs and lymph nodes. This means that 69 out of 100 people will still be alive in 5 years if the cancer has spread to nearby organs and lymph nodes.
- 12% if the cancer has spread to the liver, lungs, or bones. This means that 12 out of 100 people will still be alive in 5 years if the cancer has spread to the liver, lungs, or other organs in the body.
These numbers are taken from reports that were done at least 5 years ago, before newer treatments were available. So the actual chances of your survival are likely to be higher than these numbers.