How Much Colon Cancer Can We Prevent?

by Max Hammonds, MD

A recent report revealed that colon cancer rates have decreased 30% in people over 50 years old.

Interestingly, this good news came in March – Colorectal Cancer Awareness Month. The researchers attribute this large decline in cancer occurrence to the increased rate of colonoscopy – a visual examination of the inside of the colon by a physician, looking for and removing polyps (small growths) which can become colon cancer at some time over the next ten years. Why the decline in colon cancer? Because the rate of colonoscopy in 50 year olds has increased from 15% to 55% in the last three years.

Because colon cancer is the third most common cancer and is the third deadliest cancer, this is good news. The bad news hiding behind the wonderful headlines is that 1) 45% of the people over 50 have not had a colonoscopy, 2) in people under 50 the rate of colon cancer has increased slightly, and 3) in people who have a family history of colon cancer or have other significant risk factors for colon cancer, they should be screened (have colonoscopy) by age 40.

What are those other risk factors, besides a family history?

The next three most significant risk factors for colon cancer are: being overweight, lacking regular exercise, and eating red meat, especially salted, spiced, and packaged meat – that is, bologna, hot dogs, cold cuts, etc. Further risk factors include smoking, eating fast food, and alcohol use – as well as eating a diet low in fiber but high in salt, fat, and calories.

What’s the common factor in all of these risk factors – inflammation and irritation of the colon lining. The high cholesterol, high fat and spices irritate the colon from the inside. Smoking and alcohol irritate the colon from the outside. Being overweight and eating a diet high in protein and fat slows the transit time that food material passes through the colon, exposing the lining of the colon to the irritants.

The fiber in the diet holds water, making passage time quicker. And the microbes that live in the gut digest the fiber to make butyrate, a chemical that decreases irritation and decreases the formation of polyps. A diet low in fiber negates these good effects.

How many of these risk factors are under the control of choice by the individual? All of them except family history. By how much can maintaining ideal weight, exercising, and eating a healthy diet decrease the incidence of colon cancer? By about 50%. (See www.aicr.org for details)

Imagine how much we could improve on the good news if we could get people to make lifestyle choices that reduce colon cancer by 50 % and get their colonoscopy in a timely fashion to reduce colon cancer by 30%. Since Colorectal Cancer Awareness Month just passed, we thought you ought to be aware.