March is Colon Cancer Awareness month. Colon cancer will take the lives of nearly 55,000 Americans this year. Yet, colon cancer is preventable because with a screening colonoscopy we can easily identify and painlessly remove pre-cancerous polyps which are the precursor growths of colon cancer. As a practicing gastroenterologist, I am concerned that only about 60% of people over the age of 50 get their screening colonoscopy. In a prior blog post, I discuss 10 Myths About Colonoscopy, many of which prevent patients from getting their screening colonoscopy. What I would like to discuss in this blog post are five important facts about colon cancer.
- Colon cancer is the leading cause of cancer-related death among non-smokers.
This is a sobering fact. Among non-smokers, colon cancer kills more than lung, breast, or prostate cancer. Among smokers, lung cancer kills more than colon cancer; however, with fewer people smoking tobacco this will likely change among future generations. Colon cancer kills about 20,000 more Americans per year than deaths due to motor vehicle accidents! What are risk factors for colon cancer? Risk factors include a personal history of colon polyps, a family history of colon polyps or colon cancer, obesity, smoking tobacco, diets high in red meat, cooking meat at high temperatures (barbecuing), type-2 diabetes, and lack of exercise.
- The most common symptom of colon cancer is NO symptom.
This comes as a shock to most people. The colon is a large diameter tube that can accommodate a large growth without you knowing it. That is why you can pass stool through your colon without your awareness until your rectum has accumulated enough stool to tell you it’s time to have a bowel movement. A colon cancer the size of a walnut can easily kill you. Colon cancer will eventually lead to symptoms when the tumor size is large and often not curable. Symptoms may include rectal bleeding, a change in the size or caliber of your stool, constipation, abdominal pain, and weakness due to anemia (low blood count due to slow blood loss).
- Colon cancer starts off as a benign colon polyp.
Virtually every colon cancer first begins as a small growth from the lining of the colon. This small growth is known as a polyp and almost never produces any symptoms. The progression from a newly formed polyp to an early colon cancer can take 10-15 years. This is well documented and is known as the adenoma-carcinoma sequence. Colonoscopy saves lives primarily because it identifies polyps which can then be easily removed during colonoscopy thus preventing colon cancer from ever taking hold.
- Colon cancer is preventable.
Colon cancer is arguably the most preventable cancer. The only other cancers that might challenge colon cancer as the most preventable are skin cancers which can be detected by a dermatological evaluation. The lining of the colon can be readily examined as well during a colonoscopy which allows a physician to directly inspect the entire colon lining for polyps and other abnormalities. Polyps are easily detected and can be removed during a colonoscopy, hence removing the abnormal growth long before cancer ever has a chance of developing in the polyp. One can further help to prevent colon polyps through chemoprevention, which means taking an agent to help biochemically to prevent the formation of colon polyps and colon cancer. See my prior blog post that address this issue: ‘How Can One Help to Prevent Colon Polyps?’ Such chemoprevention agents include taking aspirin (check with your provider before doing so), vitamin D, calcium, selenium, folate, vitamin B2, vitamin b5, and beta carotene. Curcumin, derived from the superfood turmeric, has been shown to be helpful as well.
- Colonoscopy is the best test to screen for colon polyps and colon cancer.
This fact is indisputable. Colonoscopy has been shown in good clinical studies to decrease mortality by detecting polyps and early colon cancers at a stage when the cancer is curable. See my prior blog post that addresses this issue: ‘Colorectal Cancer Screening Saves Lives.’. Colonoscopy allows for the direct visual inspection of the colon lining and the removal of polyps during the colonoscopy. No other screening test for colon cancer allows for the removal of colon polyps. All other screening tests for colon cancer are purely diagnostic and not therapeutic which means that if polyps are detected they cannot be removed during that examination. In such a situation, you would be referred for a colonoscopy to have the polyps removed. What are the alternative screening tests to colonoscopy? They include CT colonography (also known as a virtual colonoscopy), barium enema, and various stool tests that either detect microscopic blood or molecular debris from polyps and colon cancer. These alternative screening tests are better than no screening test; however, colonoscopy is the gold standard for colon cancer screening.
Check out my blog post ‘Dr. Farrell’s Complete Colonoscopy Checklist‘ before your next screening.
Here’s to your colon health!
Frank Farrell, MD, MPH, AGAF