What You Need to Know About The Stages of Colon Cancer
After a colon cancer diagnosis, your gastroenterologist will try to figure out if it’s spread and how far. This is called staging. The stage of a cancer describes how much cancer is in the body, how serious it is, and how to best treat it. Your gastroenterologist will also use your cancer’s state to give you information about survival statistics.
Early-stage cancers are called stage 0. This is a very early cancer. The other stages range from I (1) through IV (4). The lower the stage number, the less the cancer has spread. A higher number means more spread. Within a stage, each letter means a lower stage. Cancers with similar stages generally have a similar outlook and are treated the same way.
Colon Cancer Staging
The staging often used for colon cancer is the American Joint Committee on Cancer (AJCC) TNM system. It’s based on three pieces of information.
T: the size of the tumor. This is determined by establishing how far the cancer has grown into the wall of the colon or rectum. The layers of the colon or rectum, from inner to outer, are:
- Mucosa, the inner lining in which nearly all colon cancers start. The mucosa includes the muscularis mucus, a thin muscle layer.
- Submucosa, the fibrous tissue beneath the muscularis mucosa.
- Muscularis, the thick muscle layer.
- Subserosa and serosa, the thin layers of connective tissue that cover most of the colon but not the rectum.
N: the spread to nearby lymph nodes. This is determined by establishing if the cancer has spread to nearby lymph nodes.
M: the metastasis (spread) to distance sites. This is determined by establishing if the cancer has spread to distant lymph nodes or distant organs.
Once a person’s T, N, and M values have been determined, this information is evaluated in a process called stage grouping. This assigns an overall stage.
The Two Types of Staging
There are two ways to stage cancer. The first type is clinical staging. During this type of staging, a gastroenterologist uses results from a physical exam, biopsies, and imagining tests to stage a cancer.
The second type of staging is pathologic staging. This is also called surgical staging. To stage a cancer using pathologic staging, a gastroenterologist examines tissue removed during an operation. Pathologic staging is often more accurate than clinical staging.
Cancer Stages and Survival Rates
The most important information that staging can provide is the survival rate. A survival rate tells you what percentage of people with the same type and stage of cancer are still alive a certain amount of time after their diagnosis. Survival rates are estimates and can’t predict what will happen in any one person’s case. It’s also important to consider that treatments improve over time, and survival rates are based on people who were diagnosed and treated earlier.
Early Detection and Survival Rates
The people with the best survival rates are those whose cancer was found early. Keeping up to date on your colon cancer screening allows for early detection. Colon cancer screening, or a colonoscopy, can actually prevent cancer by removing precancerous polyps growing in the colon. If polyps are found during a colonoscopy, your gastroenterologist will painlessly remove them and prevent the development of cancer.
The American Cancer Society recommends that people begin colon cancer screening at age 45. After the initial screening, your gastroenterologist will tell you how frequent your screenings should be in the future.
If you’re ready for your first screening or due for your next, schedule an appointment today.