Colonoscopy is the most thorough and reliable form of screening for cancers of the colon and rectum. The good news is that although colorectal cancer is the second most common cancer killer, it's also highly preventable and treatable when detected early. The bad news is that only about half the people who should be screened actually are.
During a colonoscopy, a trained gastroenterologist examines the entire colon using a tiny camera attached to the end of a flexible tube. Most cancers of the colon start as polyps, or benign growths, on the internal colon wall. However, left alone, some polyps may eventually develop into colon cancer.
Colon cancer grows slowly, which is both a blessing and a curse. Patients typically experience few symptoms when the cancer is in early stages and treatments have a high success rate. By the time the cancer produces noticeable symptoms, it's usually reached an advanced stage. Colonoscopy detects cancer early, before symptoms appear and before the cancer has a chance to spread to other parts of the body.
If your physician finds small polyps during a colonoscopy, he or she will remove them on the spot, reducing your risk they will develop into cancer. A colonoscopy also gives your physician an opportunity to take a biopsy, or sample of tissue, if needed.
You should have your first colonoscopy at 50, when your risk for colon cancer begins to increase. If you have a family history of colon or rectal cancer, you should begin screening earlier. After a baseline colonoscopy, your physician will recommend a schedule of future screenings based on your results.
Be familiar with the most common warning signs of colon cancer. If you experience any of these symptoms, see your physician right away.
- Rectal bleeding
- Constipation rem
- Abdominal pain or discomfort
- Unexplained weakness or weight loss
- Anemia
- Change in bowel habits
In the past, physicians did not consider virtual colonoscopies as reliable for colon cancer screening. They used this tool primarily to screen patients who wouldn't, or couldn't, undergo standard colonoscopy. However, doctors now say that a virtual colonoscopy can detect polyps as small as six mm (considered clinically relevant) in more than 90 percent of cases. It also has a low rate of false positive response. In the future, physicians may use virtual colonoscopies as an initial screening tool, referring patients for traditional colonoscopy when needed.
Sources:
http://acg.gi.org/patients/gihealth/colon.asp
http://www.nlm.nih.gov/medlineplus/tutorials/colostomy/htm/index.htm
http://www.cancer.gov/cancertopics/wyntk/colon-and-rectal/page6
http://www.mayoclinic.com/health/colon-cancer/DS00035/DSECTION=symptoms
http://www.nlm.nih.gov/medlineplus/ency/article/000262.htm#Symptoms
