Colorectal cancer is cancer that develops in the colon or rectum. The colon and rectum are parts of the digestive, or gastrointestinal (GI), system. The colon is a 5-foot-long muscular tube used to store waste in the large intestine, or large bowel. The colon has four main sections: ascending colon, transverse colon, descending colon and sigmoid colon. Waste matter moves through the colon to the rectum and then is passed out of the body.
Colorectal cancer starts in the inner walls of the colon or rectum and usually takes several years to develop. Colon cancer usually begins with non-cancerous colorectal polyps, small tissue/tumor growths found on the wall of the colon or rectum. Some polyps will develop into cancer; others will remain benign1.
- Pre-cancerous polyps. Also known as adenomatous polyps (adenomas), these can change into cancer.
- Benign polyps. Hyperplastic polyps and inflammatory polyps are generally non-cancerous, but should be watched.
- Dysplasia. Abnormal cells in the lining of the colon or rectum, often found in people who have had ulcerative colitis or Crohn's disease.
If polyps develop into cancer, it can grow into the walls of the colon or rectum and spread to lymph nodes or blood vessels. Once there, the cancer can quickly metastasize, or spread to other parts of the body.
Types of colorectal cancer
Adenocarcinoma is the most common type of colorectal cancer, found in 95% of cases. This cancer starts in the lining of the colon or rectum in cells that form glands that secrete mucus.
Other less common types of colorectal cancer include:
- Carcinoid tumors - Start in cells in the neuroendocrine system (nerve and hormone cells).
- Gastrointestinal stromal tumors (GISTs) - Start in special cells of the walls of the GI tract, called interstitial cells of Cajal (ICCs).
- Lymphomas - Cancers of the immune system that often start in lymph nodes.
- Sarcomas - Start in soft tissue such as blood vessels/muscles/tissues.
A screening could save your life.
Nine out of 10 people whose colon cancer is discovered early will be alive 5 years later. And many will live a normal life span1. Colonoscopy is the best way to check for polyps that might indicate colorectal cancer. Call 800-777-7775 today to schedule an appointment with a Community gastroenterologist.
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Image source: https://www.ccalliance.org/colorectal_cancer/overview.html