Colonoscopy – A Dreaded Test Prevents Deaths

Colonoscopy cartoon. (Hemera)
Colonoscopy cartoon. (Hemera)

Dr. Bharwani demonstrating the use of flexible sigmoidoscope - checks left side of the colon for average risk patient.
Dr. Bharwani demonstrating the use of flexible sigmoidoscope – checks left side of the colon for average risk patient.

Rightly so, the media immediately picked up the conclusions of a recent study (Colonoscopic Polypectomy and Long-Term Prevention of Colorectal-Cancer Deaths) published in the New England Journal of Medicine (February 23, 2012).

Among 2602 patients who had adenomas (pre-malignant polyps) removed during participation in the study, after a median of 15.8 years, had 53 per cent reduction in death from colorectal cancer.

This indeed is an important conclusion. As New York Times (February 22/12) said, “Although many people have assumed that colonoscopy must save lives because it is so often recommended, strong evidence has been lacking until now.” This study has some limitations in that it was not a double blind or randomized trial.

The Times article also says, “The new study did not compare colonoscopy with other ways of screening for colorectal cancer and so does not fully resolve a longstanding medical debate about which method is best. Tests other than colonoscopy look for blood in the stool or use different techniques to examine the intestine. All the tests are unpleasant, and people are often reluctant to have them.”

In fact, a study from Spain found that when people were offered a stool test, only 34.2 per cent took it. The figure for colonoscopy was even worse: 24.6 per cent.

One thing most physicians agree is that it is important to get some type of screening test for colorectal cancer starting at age 50. Research indicates that not every polyp turns into cancer, but that nearly every colorectal tumor starts out as an adenomatous polyp. In the general population this type of polyp is found in about 15 per cent of women and 25 per cent of men.

So, not every 50 year old and older is at risk of having colorectal cancer. Some are at average risk, some are at moderate risk and some are at high risk. It all depends on your personal and family history.

Not all doctors who do colonoscopies are good at finding polyps. Studies have shown that polyps in the right side of the colon are more often missed than on the left side.

Good news is, colonoscopy does not have to be done every year. If there are no polyps, it is recommended just once every 10 years. People with polyps are usually told to have the test every three to five years depending on the size and kind of polyp.

Colonoscopy should be used judiciously. It is invasive and expensive. It carries small risks of bleeding or perforation of the intestine. It requires sedation, a day off work, and patients must take strong, foul-tasting laxatives to clean out the intestines.

Dr. Winawer, one of the authors of the new study is quoted in the Times article saying, “Any screening is better than none. The best test is the one that gets done, and that gets done well.”

So, what are you waiting for. Talk to your doctor about your risk (average, moderate, high), your options, the advantages and disadvantages of each test and go for it. It may save your life.

Honey, where is my bottle of laxative…I said laxative not a bottle of wine.

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Colorectal Cancer Screening Program

Last week, every physician in Alberta received an envelope from Alberta Cancer Board containing Alberta’s first clinical practice guidelines for colorectal cancer screening. There isn’t much new in the protocol they advocate. This protocol has been used before and followed by many physicians in Alberta and around the world. What is new is that the protocol has now been formally accepted and promoted by various health organizations in Alberta.

Number one cancer killer in Alberta is lung cancer. What is the second leading cause of cancer death in Alberta? Of course, colon and rectal cancer. In 2004, 650 Albertans died of this disease. In Canada, 8,700 people died of colorectal cancer in 2007.

How many people over the age of 50 get screened for colorectal cancer each year? Less than 15 per cent. That is not good. Alberta Cancer Board hopes that this number will improve in the next few years.

Asymptomatic men and women who are 50 years or older, with no family history of colorectal cancer, are considered to have average risk for colorectal cancer and one of the following options is available for screening:
-Stool tests, also known as fecal occult blood tests (FOBT), yearly or bi-annually or
-Flexible sigmoidoscopy (60 cm. scope) every five years – checks rectum and left side of the colon. This is an office procedure. It picks up 50 to 70 per cent of advanced polyps and cancer or
-Combine fecal occult blood tests with flexible sigmoidoscopy every five years or
-Barium enema every five years (not used very often for screening) or
-Colonoscopy every 10 years

It is quite reasonable to choose any one of the above methods. This is better than no screening. Each method has advantages and disadvantages which your doctor will discuss with you.

It is of interest to note that Alberta Medical Association’s TOP (Toward Optimized Practice) program has launched Health Screen in Act10n (meaning 10 screening maneuvers) program to enhance screening practices among Alberta doctors.

The TOP pamphlet says that the campaign asks physicians to use a checklist of health markers when seeing patients for periodic health examinations to make sure that they have covered areas of importance which would improve the quality of their practice and enhance patient’s health in preventing disease.

Ten markers or maneuvers were selected were on the basis of best practice evidence available from various sources. These are: patient’s smoking behavior, blood pressure, tetanus/diphtheria vaccination status, PAP test, clinical breast examination, fasting glucose, lipids, mammography, colorectal cancer screening and bone density.

It would not be a bad idea for you to make a list of these markers and see where you stand. Even better would be to take the list with you when you see your doctor next time and see how you are doing. Human memory can be short or deceptive when it comes to remembering dates. Your doctor should be able to help you update your checklist.

It is not easy to stay healthy. It requires time, perseverance and sacrifice. Good luck.

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Screening for Colorectal Cancer

Dear Dr. B: What is the best screening tool for early detection of colorectal polyps and cancer? What are the guidelines for screening?

Answer: This subject is gaining more importance each day. In the month of March I was at Peter Lougheed Centre, Calgary to attend a seminar on Update on Colon Cancer and Endoscopy organized by the University of Calgary’s Division of Gastroenterology. One of the topics for discussion was on colon cancer screening guidelines.

Colorectal cancer is the fourth most common cancer. It is the second leading cause of cancer death in Canada. In 2004, 19,100 new cases of colorectal cancers were diagnosed in Canada and 8300 deaths were reported.

Screening for colorectal cancer is recommended to pick up polyps and cancer at an early stage when they can be treated effectively. Currently we do not know what the best test is for screening purposes. A variety of tests are now available, each with advantages and disadvantages.

Every individual is at risk of developing colorectal cancer. The average lifetime risk of developing colorectal cancer is six per cent. If you have any of the following risk factors then the risk increases:
-Family history of colorectal cancer or polyps
-Ulcerative colitis or Crohn’s colitis
-Presence of polyps or previous history of colorectal cancer

What is the approach to an individual with average risk of colorectal cancer?

For asymptomatic men and women who are 50 years or older with no family history of colorectal cancer are considered to have average risk and the following options are available for screening:
-Fecal occult blood tests yearly or bi-annually
-Flexible sigmoidoscopy every five years
-Fecal occult blood tests plus flexible sigmoidoscopy every five years
-Barium enema every five years
-Colonoscopy every 10 years

What is the approach to an individual with above average risk of colorectal cancer?

For asymptomatic men and women age 50 or over with a positive family history of colorectal cancer the lifetime risk of developing colorectal cancer is anywhere from 15 per cent to 80 per cent depending on how many first degree relatives had colon cancer and at what age.
-If two or more first degree relatives have had colon cancer and if one of them is under the age of 60 then colonoscopy is advised at the age of 40 or 10 years earlier than the affected first degree relative and then every five years
-If only one first degree relative has colorectal cancer and is 60 years old or older then the individual is considered to have average risk and the screening starts at age 40
-If there is a hereditary history of polyps then genetic testing and colonoscopy is advised.

Fecal occult blood tests are done by patients and stool samples are taken to a lab to detect traces of blood not visible to naked eye. If positive then the patient needs a colonoscopy in the hospital. If negative then the test is repeated yearly or every two years. If done annually death rate from colorectal cancer is reduced by 30 to 45 per cent. The test can be combined with a short scope (flexible sigmoidoscopy) which is an office procedure. We do flexible sigmoidoscopy in our office on a regular basis. This can be repeated every five years.

Barium enema and colonoscopy are done in the hospital. If abnormality is found on a barium enema then colonoscopy is required. If colonoscopy is normal then it should be repeated every ten years for an average risk person. If less than one centimeter adenomatous polyp is found then the scope should be repeated in five years. If the polyp is bigger than one centimeter then it should be repeated after three years.

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Asprin and Colon Cancer

Dear Dr. B: Does aspirin prevent colon and rectal cancer?

Answer: In the past there have been numerous reports supporting the protective effect of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) on the development of cancer.

But a recent study from the Harvard Medical School, published in the Journal of the American Medical Association (JAMA), concluded that low doses of aspirin (100 mg) taken over a long period of time (10 years) do not help prevent colon cancer. In fact, the researchers found that low-dose use of aspirin had no effect on total cancer, breast cancer, colorectal cancer or cancers at any other sites, with the exception of lung cancer. Again, the findings on lung cancer were not conclusive.

In another study, the researchers found high doses of aspirin (14 tablets of 325 mg. aspirin in a week) taken over 10 years can prevent colorectal cancer by 53 per cent. This study involved 80,000 women. If you take six to 14 aspirins a week you reduce your risk by 22 per cent.

This information is important for individuals who are at a high risk for development of colon cancer because of personal or family history. But there is a risk involved when aspirin is consumed. For every one or two women who were protected from cancer, eight developed serious bleed from the stomach and intestine.

Aspirin is not the magic pill for prevention of colorectal cancer. But there are other things one can do to prevent colorectal cancer. Limit consumption of red meat and processed meat. Maintain normal body weight. Have a regular rectal examination after the age of 40. Have your stool checked for occult blood. Report any alarm symptoms to your doctor because you may be a candidate for further investigations involving barium enema and flexible sigmoidoscopy or colonoscopy.

These investigations are also used for screening. All screening tests have advantages and disadvantages and none of the screening tests have 100 per cent accuracy rate. Screening for colorectal cancer is important and should be encouraged among healthy asymptomatic Canadians who are 50 years of age or over. But the ideal method of screening remains controversial.

There is no controversy when it comes to patients who have alarm symptoms. The alarm symptoms are: rectal bleeding, change in bowel habit, anemia, change in the caliber of your stool, loss of weight and abdominal mass. These complaints should be investigated early as colorectal cancer is the second most common cancer among Canadians and affects men and women equally.

Something to think about!

Peter Mansbridge, Chief Correspondent of CBC Television News and Anchor of The National writes in his Macleans column, “The war on terror now enters its fifth year, making it as long as the First World War, almost as long as the Second, and longer than the Korean war.” He goes on to say that as in all wars, most of the dead are young, some very young.

“Each week there seems to be at least one 18-year-old listed. That means that on September 11, 2001, those youngsters were barely in their teens – just 13 or 14. Barely into high school… Now they are dead soldiers.”

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