Colon Cancer Stages: What You Should Know
Colon cancer, also known as colorectal cancer, is a type of cancer that affects the lower portion of the gastrointestinal tract. Colorectal cancer often begins as a small growth in the large intestine or the rectal lining. Almost all colon and rectum cancers are adenocarcinomas, a type of cancer that forms from glandular tissue. After a person is diagnosed with colorectal cancer, doctors will look to see if the cancer has spread. If it has, they will do tests to determine how far. This process is called colon cancer staging.
Why Is Staging Important?
Staging helps doctors assess how much cancer is present in the body. Because cancers at any given stage often have a similar outlook, staging can help determine the best course of treatment and offers a common language for doctors to talk about a patient’s cancer.
How Is Staging Determined?
There are four types of staging used:
- Clinical staging. Assesses the extent of cancer based on physical examination, imaging studies, and biopsies of affected areas.
- Pathological staging. Used when a patient has surgery to remove a tumor.
- Post-treatment staging. Determines how much cancer remains after a patient receives therapy.
- Recurrence or retreatment staging. Determines the best treatment options for cancer that has returned.
The American Joint Committee on Cancer (AJCC) TNM system is the staging classification most often used for colorectal cancer. Colon cancer stages are based on the following three pieces of information:
- T: The size of the original tumor
- N: Whether the tumor has spread to nearby lymph nodes
- M: Whether the tumor has spread to other parts of the body
Stages of Colon Cancer
The following stages describe colon cancer, with stage 0 being the earliest stage and stage IV being the most advanced:
- Stage 0: Cancer is limited to the innermost lining of the colon or rectum and has not spread to nearby lymph nodes or other parts of the body.
- Stage I: Cancer has progressed from the innermost colon or rectum lining and moved next to the muscle layer.
- Stage II: Cancer has grown through the wall of the colon or rectum and may have invaded nearby tissues, but it has not spread to nearby lymph nodes.
- Stage III: Cancer has progressed to surrounding lymph nodes but has not invaded other body parts.
- Stage IV: Cancer has spread to distant body parts, such as the liver, lungs, or brain.
Within these five main stages, substages detail specific cancer characteristics, such as which layer of the colon or rectum wall has been reached by the tumor. Substages are identified with letters, and letters that appear earlier in the alphabet signify a lower substage.
Colon Cancer Symptoms
Symptoms of colon cancer can vary depending on the stage of the cancer. In the early stages, colon cancer may not cause any symptoms. However, as the cancer grows and spreads, symptoms may include:
- Changes in bowel habits, such as diarrhea or constipation
- Blood in the stool
- Unexplained weight loss
- Pain or abdominal cramping
- Nausea or vomiting
It’s important to note that these symptoms can be caused by many different conditions, not just colon cancer. However, you should see your doctor immediately if you experience any of these symptoms.
What Is the Prognosis for Colon Cancer?
The prognosis for colon cancer varies depending on the cancer stage and other individual factors. In early-stage cancer, when the tumor has not spread beyond the colon or rectum, the five-year survival rate is about 90%. However, if the cancer has spread to distant parts of the body, the 5-year relative survival rate drops to about 14%.
People who participate in regular cancer screening have a better chance of early detection. The earlier colorectal cancer is detected and treated, the better the prognosis.
What Can You Do?
Although colon cancer is a serious disease, it can be effectively treated if caught early. Regular colonoscopies starting at age 45 are the best way to find colon cancer early or prevent it entirely. In addition to regular screenings and a healthy lifestyle, it is important to be aware of your family history of colon cancer. If you have a family history of the disease, you may be at higher risk and should talk to your doctor about how often you should get colonoscopies.
Remember, early detection is key to preventing or catching colon cancer when it is most treatable. If you are 45 or older and haven’t had a colonoscopy, it’s time to start – schedule an appointment today!