An early colon cancer often has no symptoms whatever, so screening tests can boost survival rates by diagnosing a colon cancer before it has caused symptoms and spread to other parts of the body (Prz Gastroenterol, Jan 6, 2019;14(2):89–103). Polyps detected in any of the screening tests can be removed, which greatly improves the rates of survival.

Many doctors recommend that you start getting a colonoscopy to screen for colon cancer at age 50 and if you have no signs or symptoms of colon disease or polyps, to have another colonoscopy every 10 years until age 80. However, having a colonoscopy is expensive and can cause considerable discomfort. Furthermore, waiting 10 years for your next colonoscopy can allow time for a cancer to spread and possibly not be curable.

Doctors can now use two highly-sensitivity stool tests that are dependable screening tools for colon cancer and cause no discomfort:
• Fecal Immunochemical Testing (FIT) for blood in stool
• DNA test for cancer cells in stool (Cologuard)
The major problem with these stool tests is they are less effective than a colonoscopy in picking up colon polyps that are premalignant and can be removed before they become malignant. A colonoscopy can detect 95 percent of large polyps, while a Stool DNA (Cologuard) test) can only detect 42 percent of large polyps and Fecal Immunochemical Test (FIT) detects only 24 percent of large polyps.

Colonoscopies are Expensive
The average colonoscopy in the U.S. costs $2,750, but can range from $1,250 to $4,800 or on rare occasions more than $8,000. If these tests find no blood or cancer cells in your stool, it makes you less likely to have that cancer. A colonoscopy remains the most dependable way to diagnose colon cancer, but colonoscopies have lots of potential side effects:
• cramping, bloating or bleeding. (Make sure to tell your doctor if you are taking anti-clotting medicines such as aspirin or have heart problems)
• adverse reaction to anesthesia
• dizziness after anesthesia
• infection
• colon perforation (rare)
Call your doctor right away if you have symptoms of any of these side effects.

Modifiable Lifestyle Risk Factors for Colon Cancer
An excellent review of modifiable risk factors for colon cancer, supported by journal references, appeared in Prz Gastroenterol (Jan 6, 2019;14(2):89–103). Avoiding alcohol, tobacco, and red and processed meat consumption have been reported to reduce colon cancer risk by more than 50 percent (Nat Rev Gastroenterol Hepatol, 2016;13:691–706). A review of 13 studies found that obesity and physical inactivity are major risk factors for colon cancer (BMC Cancer, 216;16:157; Eur J of Cancer Prevention, 2013;22:419-505). A regular exercise program and maintaining a healthy weight reduces risk for colon cancer by 25 to 50 percent (Eur J Cancer Prev, 2013;22:492–505).

Diabetes and insulin resistance increase your risk for colon cancer. The CDC estimates that more than 30 percent of diabetics never know that they suffer from diabetes, primarily because having a normal fasting blood sugar below 100 mg/dL) does not rule out diabetes. If you have a blood sugar greater than 145 mg/dL one hour after eating a full meal, you are suffering significant cell damage from your diabetes and are at increased risk for colon cancer (BJ, 2015;350:g7607). A review of 29 prospective studies involving 62,924 diabetics found a high rise in colon cancer in diabetics (Eur J Epidemiol, 2011;26:863–76). A study of a half million diabetics found a significant increase in the rate of colon cancer (J Epidemiol Commun Health, 2018;72:919–25). See Lifestyle Changes to Prevent and Treat Diabetes

My Recommendations
Everyone should be checked for colon cancer from age 50 onward because you are more likely to be cured from colon cancer if it is diagnosed and treated before it has spread to other parts of your body. Colonoscopies are the most accurate way to check for early colon cancer, but they are expensive, often painful and can have significant side effects. Doctors also use two fairly dependable tests to screen for colon cancer, looking for blood and cancer cells in the stool.

The recent medical literature suggests that lifestyle factors that increase risk for colon cancer include:
• eating mammal and processed meats, sugar-added foods and drinks, fried foods, and ultra-processed foods and not eating enough fruits, vegetables, unground whole grains, beans, seeds and nuts
• being overweight, particularly having too much fat in your belly
• not being active and not exercising
• damaging your DNA by smoking and drinking alcohol
• being diabetic or just having a high rise in blood sugar after eating

Correcting these lifestyle factors can reduce your risk for colon cancer, and should be part of any treatment program for colon cancer along with surgery, chemotherapy and radiation.