Colon Polyps and Cancer

Medical Conditions

Author, Frank W. Jackson MD
Updated 2014


Colon cancer is very common and is a leading cause of cancer deaths. In almost every case, colon cancer starts out as a colon polyp. Therefore, removing polyps prevents colon cancer. If someone in your immediate
family, parents, brother, sister, children – has had colon polyps, and, especially colon cancer, then you are at increased risk. African Americans have an increased death rate from the disease. The bottom line is that almost anyone can develop colon cancer and that it is preventable by removing polyps.

  • Anyone can get colon cancer.
  • If someone in your family has it, you are at increased risk.
  • Colon cancer is preventable by removing colon polyps.

What is a Polyp?

A polyp is a benign growth that can become cancerous. These fleshy tumors grow on the inside lining of the colon and are shaped like a mushroom or dome-like button. They may be as small as a pea or larger than a plum. They start out benign but then some of them become malignant as they get larger. The larger the polyp, the more likely it will have cancer within it.

What Causes Colon Polyps and Cancer?

The science on this question is slowly becoming clear. In some people, it is determined by genes. Some genes cause a huge number of colon polyps at a very early age. Colon cancer develops in all these individuals and the
only cure is to remove the colon. Other cancer-causing genes are not so devastating but they are still important.  However, there are many people with colon cancer with no family history of polyps or cancer at all.

The other major contributing factor is diet. What we eat and what we don’t eat makes a difference. I refer you to the section below on prevention, but in a word, those who consume large amounts of red meats, saturated and trans fats and who eat low quantities of fruits, vegetables and fiber are at increased risk. Your calcium intake may also be a factor. You can control your diet.

  • Cancerous genes can cause colon polyps and cancer.
  • Excessive red meats, saturated fats and inadequate vegetables, fruits, fiber, and perhaps calcium, are key risk factors.
  • Smoking cigarettes for over 30 years is another risk factor.

What Are the Signs and Symptoms?

With polyps, the answer is nothing. They occur painlessly and can only be detected by screening colonoscopy. With cancer, the following symptoms and signs may occur. Unfortunately, when they do, the tumor may be fairly large and advanced. See your physician immediately if you have any of the following:

  • rectal bleeding
  • maroon, dark or even black bowel movements
  • recurrent, frequent abdominal cramps or gas
  • unexplained weight loss or fatigue

How Do You Make the Diagnosis?

The first thing that is done by the physician is to take a careful medical history and do a digital rectal exam. Colonoscopy is almost always recommended as this is the only way to see the entire colon, remove polyps and do biopsies. Colonoscopy uses a lighted, flexible tube and is done under light sedation. Virtual colonoscopy uses an advanced form of x-ray. It is fairly good at detecting polyps and tumors, but of course, these can not be removed or biopsied. An older exam called a barium enema is helpful at times, but not often done anymore.

  • medical history
  • digital rectal exam
  • colonoscopy


The diet of North Americans and Europeans has dramatically changed over the past several hundred years. As we live day to day and year to year, we just don’t see it. We assume this is the way people have always eaten. However, in the distant past, plant food – fruits, vegetables, seeds, fiber – was the mainstay of the diet. For the ordinary person, meat was not readily available and not often eaten. My, how things have changed! For detailed dietary recommendations, go to Colon Polyps and Cancer Dietary Therapy.

Red Meats and Saturated Fats

There are substances in red meat and saturated fats that, when broken down by bile salts, enzymes and colon bacteria, are not nice to the cells that line the colon. In fact, experimentally in animals, certain cancerous materials – carcinogens – may appear. The exact role of these factors is uncertain in humans, but it is an observed fact that people who eat lots of red meat and saturated fat have an increased incidence of colon cancer.

Fruits, Vegetables, Grains

The same thing applies in reverse. Those who consume the recommended 5 servings per day of fruits and vegetables have fewer colon cancers. What is the reason? Well, the antioxidants in colorful vegetables may be one answer as these are known to fight cancer. Another is the fact that cruciferous vegetables, cauliflower, broccoli, Brussel sprouts, and cabbage contain large amounts of a known anti-cancer chemical called sulforaphane. Whatever the reason, these plant foods are associated with lower rates of colon cancer.


Rural Africans eat over 50 grams of fiber a day and have little colon cancer. Indeed, they have few, if any, ills that affect the colon in the Western World such as chronic colitis and diverticulosis. Yet, when this ethnic group comes to North America, they have a high incidence of all these diseases. This may be a coincidence, but I doubt it. Fiber in plant food is now known to have many health benefits. A more recently uncovered form of soluble plant fiber is Prebiotics. These fibers fuel the good bacteria in the colon producing substances which have been clearly shown to be healthy. In some animal studies, they reduce the occurrence of experimental colon cancer. We still don’t know the full cancer prevention benefits in humans but they are likely to be found to be important.


Calcium regulates the rate of growth of cells that line the colon. There is now considerable experimental and epidemiological evidence that adequate calcium helps to control the rate of growth of colon cells. In addition, certain prebiotic plant fibers enhance the absorption of calcium and magnesium. Calcium intake should be high, over 1500 mg per day. Furthermore, the current recommendation for vitamin D, which helps increase calcium absorption and bone strength, is 800 to 1200 units a day.


There is evidence that aspirin may aid in colon cancer prevention. Check with your physician on the use of aspirin.


A 2008 study has added one more reason to stop smoking. For those who smoked for over 30 years, there is a statistically increased risk of colon cancer. Smoking seems to interfere with the natural cancer defense mechanisms in the body.


Colon cancer and polyps are very common. If polyps are detected early, cancer can be prevented by removing the polyps. Eating the proper diet is a major preventative step everyone can take. You can’t change your genes but you can change what goes into your mouth and reaches the colon. In summary:

  • Decrease red meat and saturated fat intake.
  • Increase fruits, vegetables, grains, and fibers – including prebiotic fiber.
  • Increase calcium and vitamin D to recommended levels.
  • Check with your physician about daily aspirin.