Colon Cancer - a Most
Preventable Killer
Colon cancer and rectal cancer have many features in common and are often referred to together as colorectal cancer. It is a slowly progressing disease that may be present without symptoms for at least several years.
Colon cancer is the third most common cancer found in men and women in this country. Each year 130,000 Americans are diagnosed with colorectal cancer, and 56,000 die from the disease.
Colon cancer begins in the digestive system known as the GI (gastrointestinal) system. This is where food is changed to create energy and rid the body of waste matter.
What is it?
Cancer can start in any of the four sections of the colon (ascending, transverse, decending, sigmoid) or in the rectum. There are several layers of tissues in the walls of each of these sections and of the rectum.
Colon cancer starts in the inner layer and can grow through some or all of the other layers. The stage (extent of spread) of a cancer depends largely on which of these layers it affects.
How it begins
Usually, colon cancer begins as a polyp. Polyps are either mushroom-shaped or flat and may be large or small.
These are the most common :
Adenomas. These polyps have the potential to become cancerous and are typically removed during screening tests.
Hyperplastic polyps. Often less than 1/4 inch in diameter, these polyps are rarely a risk factor for colorectal cancer.
Inflammatory polyps. Although not a significant risk, they may follow a bout of ulcerative colitis and having colitis increases your overall risk of colon cancer.
It is always best to screen for these polyps every few years, and prevent them from developing by having them surgically removed. By doing so, one dramatically reduces the risk of developing and dying from colorectal cancer.
Symptoms of colorectal cancer
In most cases, colorectal cancer can be detected early. Just because you have these symptoms does not mean you have cancer. Also, many people with colon cancer have no visible symptoms. Hence, the importance of regular screenings. The classic symptoms of colon cancer are:
- A change in bowel habits such as diarrhea, constipation, or narrowing of the stool that lasts for more than a few days
- A feeling that you need to have a bowel movement that doesn't go away after doing so
- Bleeding from the rectum or blood in the stool
- Cramping or steady stomach pain
- Weakess and tiredness
Screening for colorectal cancer
Stool Blood Test (Fecal Occult Blood Test or FOBT): This test is used to find small amounts of hidden (occult) blood in the stool.
Flexible Sigmoidoscopy (flex-sig): A sigmoidoscope is a slender, lighted tube placed into the lower part of the colon through the rectum. This allows the doctor to look at the inside of the rectum and part of the colon for cancer or polyps.
Colonoscopy: The colonoscope is a longer version of the sigmoidoscope. It allows the doctor to see the entire colon. A small piece of tissue called a biopsy may be removed to look at under a microscope to see if cancer is present.
Barium enema with air contrast: A chalky substance is used to partly fill and open up the colon.
Virtual colonoscopy: Air is pumped into the colon to cause it to expand, then a special CT scan is done.
Your doctor will order a blood count to see if you are anemic. People with colorectal cancer are often anemic because of intestinal bleeding.
Ultrasound uses sound waves to produce a picture of the inside of the body, another tool to find signs of cancer. An MRI, chest x-ray, PET scan, or angiogram may also be used to detect cancer.
You can be at risk
Several risk factors increase a person's chance of getting colorectal cancer:
- Your risks increase if you have close relatives who have had this cancer.
- A history of polyps and ulcerative colitis where the colon has been inflamed over a long period of time can increase your risk.
- If you are over 50, overweight, smoke, sedentary, and drink heavily, your chances go up for having colorectal cancer.
- A diet of mostly foods high in fat and low in fiber can heighten your risk for this type of cancer.
Treatment
Your treatment and the outlook for your recovery depends on the stage of your cancer. Staging is the process of finding out how far the cancer has spread. Surgery may be all that is needed in early stages of cancer. Other treatments such as chemotherapy or radiation therapy may be used for more advanced stages of cancer.
Surgery is the primary treatment for colon cancer. The surgeon removes the part of the colon that is cancerous, along with some surrounding normal tissue so no cancer is left behind. If your cancer is small, localized in a polyp and in a very early stage, The surgeon may be able to remove any small, localized polyps during a colonoscopy.
Chemotherapy destroys cancer cells through drugs. Chemotherapy can be used to destroy cancer cells after surgery or control tumor growth. If your cancer has spread, chemotherapy may be recommended along with radiation therapy.
Radiation therapy uses X-rays to destroy any cancer cells that might remain after surgery, to shrink larger tumors before an operation so they can be removed more easily, or to relieve symptoms of colorectal cancer.
Prevention
By having regular colon screenings, you can reduce your risk. You can protect yourself by making a few simple changes in your diet and lifestyle.
For many years most health authorities have advocated a diet higher in whole grains, fruits and vegetables and lower in fatty foods and red meats.
Fiber may reduce the risk of colon cancer. According to some theories, fiber works as a "colonic broom," sweeping carcinogens out of the large intestine before they can do damage.
Insoluble fiber speeds digested food through your intestine which may reduce the time your colon is exposed to cancer-promoting substances during digestion. It's not yet clear whether other ingredients in high fiber foods or just fiber alone protects against cancer.
Controversy . . .
A study published in NEJM, in which the Harvard School of Public Health examined data from it's long-running Nurses' Health Study (which since 1980 it has been tracking the diet and health of 88,757 women). With 16 years of follow-up, the research team uncovered no connection between dietary fiber and risk of colon cancer.
NEJM published results from two studies that looked at diet and colon cancers. Both studies found no evidence that a low-fat, high-fiber diet protects against the recurrence of colorectal cancers.
In a May 2000 article published in Hippocrates, Peter Jaret reports even so, there is much reason to believe that these diets do in fact help to prevent colorectal cancer.
The evidence has always been ambiguous. The disease is extremely rare in Africa where diets are quite high in fiber. But their diets differ in many other ways from a Western diet. They eat much less red meat and sugar, and alcohol consumption is non existent.
. . .and common sense
In an analysis of dozens of studies from around the world published in 1997, the
American Institute for Cancer Research
along with the
World Cancer Research Fund
"found reasonable evidence that a diet rich in vegetables does lower colon cancer risk."
Red meat and excessive alcohol consumption appear to increase the danger.
Gene Spiller, PhD, a leading expert on fiber, notes that a Western diet with a marginally low amount of daily fiber is not enough to protect against colon cancer. Many traditional diets are made up of 40 to 60 grams of fiber. Most Americans consume only 13 grams,less than half the recommended amount.
And, to create even more questions about the Nurses Health Study, the May 2003 issue of the British Journal Lancet in an article entitled
Europe-Wide Study Finds Fibre Can Cut Colon Cancer Risk By Up To 40%
discusses the results of a study by Dr. Sheila Bingham and Dr. Nick Day from the British Medical Research Council Dunn Human Nutrition Unit, University of Cambridge; Dr Elio Riboli the WHO International Agency for Research on Cancer, Lyon, France; and colleagues from the European Prospective Investigation into Cancer (EPIC).
They concluded that "People consuming an average of 35 g fibre a day can cut their risk of colorectal cancer up to 40%, compared to people who consume an average of 15 g per day . . ."
Peter Jaret goes on to say, "Perhaps the biggest flaw of the Harvard study is the failure to account for the wide range of fiber types found in foods that are plant-based. Celery has a very different fiber from that found in brown rice or citrus. Raw broccoli has a very different fiber structure than when cooked.
"A complete understanding of dietary fiber's health impact may come only after researchers begin to refine the biological effects of certain kinds of fiber."
For now, it is still a good bet to count on a high fiber diet to support one's overall program for wellness and the prevention of diseases, such as colon cancer and rectal cancer.
Whether it turns out to be the fiber, fiber type, phytochemistry, or just the plain "good Karma" of whole foods, the ultimate source of the benefit doesn't matter. Observation shows that it works for some populations, common sense still predicts that it will work for us.
And science is often the last to explain why.
Feel free to search through the many links we offer on easy, tasteful, and healthful high fiber recipes and a high fiber diet to add to your health and wellness program.