Cancer of colon and rectum / polyps of colon and rectum

Colorectal cancer is the second most common cause of death from cancer overall, and ranks third in both women (after lung and breast cancer) and men (after lung and prostate cancer).

Scientists believe that majority of the colon cancers develop from colon polyps (precancerous growths on the inner surface of the colon). After turning cancerous, the cells can then invade or spread (metastasize) to other parts of the body.

Colon cancer is preventable by removing colon polyps before they turn cancerous. Colon cancer is curable if resected before the cancer spreads.

Screening tests

• Stool occult blood test: Stool occult blood test is a chemical test to detect trace amounts of blood in stool. It is inexpensive and easy, though not always accurate. Some cancers are not detected by the test, and many positive tests are not caused by cancer.
  
  
• Flexible sigmoidoscopy: Flexible sigmoidoscopy is a relatively quick and easy office procedure that allows direct visualization and biopsy of suspicious lesions from the distal portion of the colon, but causes some discomfort, and is not as thorough as colonoscopy.
  
  
• Colonoscopy: Colonoscopy allows visualization of the entire colon and is the most complete and thorough test, but often requires intravenous sedation, is much more expensive, and is not covered by some insurance for screening. Although screening colonoscopies may have a slightly higher risk of complications than flexible sigmoidoscopies, both screening tests are very safe when performed by trained professionals.

Who to test and how often

All healthy subjects should have stool occult blood tests and flexible sigmoidoscopy at age 50, followed by stool occult blood annually and flexible sigmoidoscopy every five years.

Alternatively, instead of flexible sigmoidoscopy, all healthy subjects can undergo screening colonoscopy at age 50 and then every 10 years if tests remain normal and there is no prior history of polyps or cancer.

Higher risk subjects (individuals with family history of colon polyps and cancer, long standing ulcerative colitis, or prior personal history of colon polyps or cancer) need colonoscopy earlier and at shorter intervals.

Benefits of early detection

Stool occult blood test, flexible sigmoidoscopy, and colonoscopy have been documented to reduce colon cancer mortality by:

1. Preventing colon cancer by identifying and removing polyps before they become cancerous
   
   
2. Increasing cancer cure rate by identifying early cancer at a treatable stage before the cancer has spread (metastasized.)