What is colorectal cancer?
Colon cancer is 90% curable if caught early -- if caught late, it is 90% fatal. Colon cancer is the second leading cause of cancer death in North America. In 2009 the Canadian Cancer Society estimates that 22,000 Canadians will be diagnosed with colorectal cancer and 9,100 of us will die of it. Put another way, 1 in 14 men and 1 in 15 women will be diagnosed with colorectal cancer. Colonoscopy is the best test to prevent colon cancer.
How does colorectal cancer start?
Most cancers develop on the inner lining of the large bowel from gland-type polyps. You can think of polyps as flat lesions, like a pitcher's mound in baseball, or as pedunculated lesions like a mushroom. Some polyps are harmless and others grow to become cancerous. The pathway from normal mucosa, through a polyp stage to a cancer takes about ten years on average. Some cancers are more aggressive and grow more quickly; others more slowly. The photograph shows two polyps and a cancer.
What are the signs of colorectal cancer?
Often, there are none. Colon cancer may lie hidden in the body until it is very large. By then, it is often too late to cure. Common signs and symptoms include:
- blood in your stool
- a change in your bowel habits
- abdominal discomfort, cramps, gas pains
- a feeling of not being able to empty all of your stool during a bowel movement
- weight loss and fatigue
- a mass that can be felt on abdominal or rectal examination
What are the risk factors?
- age over 50 (age over 45 in African-Americans)
- a family history of colon cancer
- a personal history of polyps
- inherited disorders that predispose to cancer (FAP and HNPCC)
- inflammatory bowel disease like Crohn's disease or ulcerative colitis
- red meat and processed meat consumption
- alcohol
- obesity
- sedentary lifestyle
- diabetes
- smoking
- prior abdominal radiation therapy
