The colon is composed of four sections:The rectum receives waste matter from the colon and stores it before it exits the body through the anus.
What Is a Polyp, and Does It Cause CRC?A polyp is a group of cells that can grow inside the colon and potentially become cancerous. Polyps can be:
Some types of polyps, like hyperplastic polyps, which grow near the end of the colon, remain benign, meaning they are not cancerous. The adenomatous polyps, however, can become cancerous over time, (also called pre-cancerous). Sessile serrated polyps and traditional serrated adenomas have a higher risk of developing into CRC.
If a polyp is larger than 1cm or if multiple polyps are present, it may suggest that a person is at a high risk of developing CRC. If a polyp becomes cancerous, it can grow into the wall of the colon or rectum and eventually grow into the blood vessels or lymph vessels. This is how the cancer can spread to other organs in the body (metastasis).
Additional information on polyps and their risks can be found here.
Who Is at a High Risk of Developing CRC?The risk of CRC increases with age, and it is most commonly seen in adults over the age of 50 years. Men and women are equally likely to get colon cancer, but men have a higher risk of developing rectal cancer than women. A family history of colorectal cancer, inflammatory bowel disease (including ulcerative colitis or Crohn’s disease) may also increase a person’s risk of developing CRC. Also, a personal history of inflammatory bowel disease, colorectal polyps, or CRC can put you at high risk for CRC. Race is also a risk factor: African Americans have >20% higher incidence rate of CRC than white people.
You can read more about risk factors and screening here.
Stages of CRCCRC staging is based on how far the cancer has spread. This information is used by your doctor to decide the course of treatment. Treatment-related information can be found here.
Stage 0: This is the earliest stage of CRC in which the cancer has not grown past the inner layer of the colon or rectum
Stage 1: The cancer has not spread to the lymph nodes but has grown past the inner layer of the colon or rectum (T1 or T2, N0, M0)
Stage 2: This is sub-classified as:
Stage 3: This is sub-classified as:
Stage 4: This is sub-classified as:
Recurrent: Cancer that has returned following prior treatment.
Details on what T, N and M stand for can be found here.