Tag: colonoscopy

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What to Use for Bowel Cleansing Prior to Colonoscopy?

Dear Dr. B: I have been booked for a colonoscopy. I know I have to have my bowel cleaned out for this test to be successful. I am worried about using Fleet Phospho-soda (oral sodium phosphate product) bowel cleansing laxative because of the recent negative media reports. What should I do, doctor?

Answer: US Food and Drug Administration (FDA) issued an alert in December, 2008 which said, “FDA has become aware of reports of acute phosphate nephropathy, a type of acute kidney injury, associated with the use of oral sodium phosphate products (OSP) for bowel cleansing prior to colonoscopy or other procedures.”

FDA also says that in some cases when OSP is used for bowel cleansing, kidney failure has occurred in patients without identifiable factors that would put them at risk for developing acute kidney injury.

FDA recommends, in light of the risk of acute phosphate kidney injury, over-the-counter laxative OSPs should not be used for bowel cleansing. Consumers should only use OSPs for bowel cleansing pursuant to a prescription from a healthcare professional.
Fleet Phospho-soda has been used for many years, on millions of people, in many countries. It has been popular because of low cost and small volume of fluid to drink. The incidence of side effects is minimal in healthy individuals. There are three dangers associated with OSP in venerable patients who have heart failure or kidney disease – dehydration, electrolyte imbalance and phosphate injury to kidneys.

OSP is popular amongst physicians because it has been found to be a better bowel cleansing preparation than many other similar products.

FDA’s warning regarding kidney injury with OSP is of real concern to physicians and patients. A study published in the American Journal of Gastroenterology (103(11):2707-16, 2008 Nov.) concluded that in patients with preexisting kidney disease, OSP use was associated with an increased risk of kidney dysfunction. Their suggestion was to measure the kidney function before OSP administration in order to avoid its use in patients with renal disease.

Is bowel preparation before colonoscopy a risky business for the kidneys? This is the title of an article in Nature Clinical Practice Nephrology (4(11):606-14, 2008 Nov.). It says that in 2004, five cases of irreversible renal failure after bowel preparation with OSP were reported.

The authors say that more recently, several retrospective studies have shown that the incidence of acute kidney injury after OSP use is in the range of one to four per cent, similar to the incidence of contrast kidney disease in patients who undergo special x-rays where contrast dye is used.

During bowel preparation physicians should watch for and correct any fluid and electrolyte imbalance. Patients should be checked for kidney function and serum phosphorus level after colonoscopy. Other option would be to use alternative bowel cleansing agents.

What should you do if you are going for a colonoscopy? If your doctor wants you to use Fleet Phospho-soda to cleanse your bowel then your kidney function should be normal and you should have no cardiac problems like heart failure. The risk of kidney damage in healthy individuals is about one to four per cent. There are other bowel cleansing agents in the market. You can discuss with your physician what are your best options for a good clean out.

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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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Colonoscopy

Recently, Dave turned 50.

Over the years, he has been very conscious of his health. He eats low fat, high fibre diet. He believes in the dictum, “Those who live by the sweets, die by the sweets.” He is careful about his weight. He exercises regularly – 30 minutes each day, five times a week. He gets his prostate checked.

“So, Doc, what’s missing? Is it time for colonoscopy? Is it the best test for prevention and early detection of colorectal cancer?

Dave has no risk factors and no symptoms of colon and rectal cancer. So, here are the questions:

1. Should a 50-year-old asymptomatic individual undergo screening tests for prevention and early detection of colon and rectal cancer?
2. If yes, what is the best test – is it colonoscopy?

It is unfortunate that prevention and early detection of colorectal cancer does not get the same publicity as breast and prostate cancer. Last time media paid some attention to this subject was when the former U.S. President Ronald Reagan was found to have precancerous colonic polyps. That was many years ago!

Some young prominent Canadians have had colorectal cancer. Recently, Pamela Wallin, 48, broadcaster and author was diagnosed and treated for colorectal cancer. Former leader of the Alberta Liberal Party and Leader of the Opposition in Alberta Legislature, Lawrence Decore, died from colorectal cancer at a young age. Former Premier of Prince Edward Island, Joe Ghiz, died of colorectal cancer at age 51 (1945-1996).

Answer to Dave’s first question: Yes, there is evidence to suggest that asymptomatic 50 year olds should undergo screening for colorectal cancer.

Answer to Dave’s second question is not that straight forward. The screening tests recommended by the Canadian Task Force on Preventive Health Care (discussed here on August 9th) for asymptomatic people over the age of 50, who are at normal risk, are:

1. Annual or biennial (every two years) fecal occult blood tests (to check for non-visible blood in the stool)
2. Flexible sigmoidoscopy (an office procedure) – probably every five years.

Unfortunately, one-quarter of colorectal cancers or serious precancerous lesions may be missed by these tests.

Colonoscopy is considered the gold standard. Some experts suggest colonoscopy every 10 years for asymptomatic individuals after the age of 50. In an editorial in the New England Journal of Medicine (August 23), Dr. Allan Detsky of University of Toronto says, “I recommend a single screening colonoscopy at the age of 50, with perhaps another in 10 to 15 years if no precursor lesions are found.”

But can we afford colonoscopy for all asymptomatic Canadians over the age of 50? Probably not! Then what should one do? The best thing is to discuss your concerns with your family doctor and he can assess your risks and order appropriate tests. Blood test – CEA –is not a good test for screening and is not recommended for this purpose and should not be done.

Although screening for colorectal cancer should begin routinely at the age of 50, adherence to recommendation is 50 per cent or less. This is unfortunate and there is no mechanism to ensure better compliance.

In Canada, colorectal cancer is the third most common cancer. Both sexes are equally affected. Last year, about 17,000 Canadians were diagnosed with colorectal cancer and about 6500 died from this disease. So, Dave, you should undergo screening and my recommendation would be colonoscopy.

Have I had one? Yes.

Dave is a composite character representing a typical patient.

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