Colorectal cancer is a term often used to refer to cancer of the colon and rectum. Together, the colon and the rectum make up the large intestine, with the rectum being the last few inches or centimeters of the colon. Stage 4 colorectal cancer is an advanced stage of the disease in which cancer that began in the colon or rectum spreads to other areas of the body. The earlier colorectal cancer is diagnosed, the better the chances of recovery. Usually, most people with stage 4 colorectal cancer are not curable.
Staging is a process in which a disease is labeled according to how far the spread is from the original site. With colorectal cancer, there are two types of staging: clinical and pathologic. Clinical staging is the stage derived from a physical exam and pathologic staging is the stage determined after surgery. Both types of staging are based upon the same factors and can differ from one another. Though there are varying types of staging systems, in general, the higher the stage number, the more advanced the disease.
There are five stages of colorectal cancer, ranging from stage 0 to stage 4. Stage 0 colorectal cancer is the earliest stage in which the cancer is present in the innermost layer of the colon or rectum. Stage 1 colorectal cancer is when the cancer is still contained within the colon or rectum, but has not spread beyond the inner layer. Stage 2 colorectal cancer is when the cancer has spread through the wall of the colon or rectum, but not to nearby lymph nodes. Stage 3 colorectal cancer is when the cancer has reached the lymph nodes.
Stage 4 colorectal cancer is the last, and most advanced, stage of the disease. At this stage, the disease is determined to have traveled beyond the original site and affected other areas, such as the liver or the lungs. Cancer that spreads behaves just like the type of cancer it is, even though it is not in an area where it originated. For example, colorectal cancer that spreads to the liver behaves like colorectal cancer, not liver cancer.
It is easy to see why stage 4 colorectal cancer is much more difficult to treat than earlier stages of the disease, as the spread is wider. Since this is so, treatment of stage 4 colorectal cancer usually requires more than surgery. Other treatment methods used in combination with surgery to treat stage 4 colorectal cancer are chemotherapy and radiation therapy.
