What is Colorectal Cancer?
Colorectal cancer starts in the colon or the rectum. These cancers can also be referred to separately as colon cancer or rectal cancer, depending on where they start, though they have many aspects in common.
This type of cancer usually develops slowly over the course of a number of years, often beginning as a non-cancerous polyp on the inner lining of your colon or rectum. Polyps are usually benign, or not cancerous. If not removed, they can evolve into cancer but don’t always. It depends on the type of polyp.
- Adenomatous polyps (adenomas) are polyps that can change into cancer, and are referred to as pre-cancerous.
- Hyperplastic polyps and inflammatory polyps are usually not pre-cancerous.
Another kind of pre-cancerous condition is called dysplasia. Dysplasia is an area in the lining of the colon or rectum where the cells look abnormal (but not like true cancer cells) when viewed under a microscope. These cells can change into cancer over time. Dysplasia can also be seen in people who have had diseases such as ulcerative colitis or Crohn’s disease for many years. Both ulcerative colitis and Crohn’s disease cause chronic inflammation of the colon.
What are the Risk Factors of Colorectal Cancer?
A number of factors can increase a person’s risk of developing colorectal cancer. The good news is that there are steps you can take to protect yourself. In most cases, you can prevent colorectal cancer by undergoing screening to detect and remove polyps from the colon before they become cancerous. This examination is called a colonoscopy.
Many factors can increase your risk of developing colorectal cancer. Some are beyond your control, but others can be affected by your lifestyle.
Colorectal Cancer Stages
If you are diagnosed with colon cancer, your doctor will determine the stage of the disease.
Staging is a way of classifying cancer by how much disease is in the body and where it has spread at the time of diagnosis. This helps us to plan the best way to treat the cancer. Once the staging classification is determined, it stays the same even if treatment works or the cancer spreads.
Stage 0:
- Abnormal cells are found in the inner lining of the colon. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 also is called carcinoma in situ.
Stage 1:
- Cancer has formed and spread into the first (submucosa) or second (muscle) layers of the rectal wall. It has not spread outside of the rectum.
Stage 2:
- Cancer has spread outside of the rectal walls into the surrounding fat or nearby tissue. It has not gone into the lymph nodes. It is divided into stages: IIA, IIB or IIC depending on the extent of local tumor involvement.
Stage 3
- Cancer has spread to nearby lymph nodes. It has not spread to other parts of the body. It is divided into stages IIIA, IIIB or IIIC depending on the extent of local tumor involvement and the number of lymph nodes that contain cancer.
Stage 4
- Cancer has spread to other parts of the body, such as the liver, lungs or ovaries. It is divided into stages IVA, IVB and IVC depending on the number of different parts of the body to which the cancer has spread.
Colorectal Cancer Treatment
Treatment
Treatment for colorectal cancer can vary depending on whether the tumor is located in the colon or rectum.
Learn About Our Treatment Options