Number 35 June 26, 2004
Welcome to another e-newsletter from Three Rivers Endoscopy Center. Our physicians and nurse practitioner provide this information to help improve awareness in matters of health and nutrition. Each issue focuses upon a particular topic that we feel will be of interest.

Collecting a stool specimen for your doctor... Okay, I admit it's gross. But, so is dying of colon cancer, especially one that could have been easily prevented. What I am referring to is a common test that your family doctor may suggest - the stool Hemoccult card test. Every day in the office I interview patients who received a test kit from their doctor, but never bothered to collect and return the stool specimen. The American Cancer Society recommends that all adults over 50 have this simple screening test annually, but less than 25% are tested. To see why this is important, read on.

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The Stool Hemoccult Test

by Robert Fusco, MD

Tina: How a simple stool test saved her life....

Tina F. is a 52-year-old school psychologist who sees her gynecologist every year for a routine checkup. Like many women, she does not have a family doctor, but uses her gynecologist as her personal physician. This year her doctor suggested that a routine stool Hemoccult test be performed in addition to her annual blood tests and physical exam. As she left the office, the nurse gave her a Hemoccult card test kit and instructions. Tina collected the stool specimens as instructed and mailed the card back to her doctor's office for testing. She was surprised to receive a letter from her doctor the next week informing her that the Hemoccult test found traces of blood in her stool. Tina was especially surprised since she never had any problems with bowel movements and never noticed any blood in her stool. She was referred to our office and a colonoscopy exam was performed to determine the cause of the bleeding.

The colonoscopy exam went well and found the cause of Tina's bleeding - an inflamed colon polyp that was located in her right colon. It was slowly oozing small amounts of blood and was the source of the trace of hidden blood in the stool. The polyp was removed during colonoscopy (see below). It was a simple outpatient procedure and she was back to work the next morning.

Tina was pleased that her problem could be cured with a simple painless outpatient procedure. The polyp was sent for a biopsy. We called Tina the next week and informed her that she was very lucky. The biopsy showed that her polyp was "highly dysplastic with carcinoma-in-situ bordering on adenocarcinoma" - about as close as you can get to cancer, without actually being malignant. Her gynecologist did her a great service by being thorough and discovering her rectal bleeding even before it was visually apparent. The discovery and removal of this colon polyp saved Tina from having to deal with colon cancer in her future and probably saved her life. She will be scheduled to return for a follow-up colon exam in the future.

What is a Hemoccult test?
The Hemoccult test, a product of SmithKline Diagnostics, Inc., is a simple screening test which detects blood in the stool (bowel movements). It is a very sensitive test and can detect a small trace of blood even before it is visible to the naked eye. In medicine, the prefix "heme" refers to blood, as in "hematology". Blood that is hidden from view is called "occult" bleeding (nothing to do with witchcraft), hence the name Hemoccult for "hidden blood".

Why do this test?
Prevention - the purpose of the stool Hemoccult test is to help prevent colon cancer by searching for hidden (occult) blood in the stool even before the individual can see it. As in the above example, finding a trace of intestinal bleeding in the early stage can prevent colon cancer. The American Cancer Society estimates that over 135,000 Americans will develop colorectal cancer this year. Not only is this a common disease, it is quite sneaky. In fact, many patients with colon cancer are incurable when they have their first symptom. Despite undergoing the rigors of heroic treatment such as surgery, radiation, and chemotherapy, they succumb to the disease. In advanced stages, the overall cure rate is quite low - less than 10% are treated successfully. Over 56,000 Americans died last year from colon cancer.

However, when colorectal cancer is detected in an early localized stage, up to 90% of colorectal cancers can be treated successfully. This means that earlier detection could save thousands of lives each year. In some cases, the Hemoccult test will show hidden blood in the stool in early curable stages of colon cancer. Even better, as in this case, the Hemoccult test may be positive even before cancer cells have developed.

How is it done?
It is quite simple. Each Hemoccult kit contains a special card with three flaps on the front and three wooden sticks. Beneath each flap are two test windows. To complete the test, you are asked to place a thin smear of stool (bowel movement) onto each of the two windows. You do this for three consecutive bowel movements and simply mail the completed card back to your doctor's office in the special envelope.

To maximize the accuracy, some special precautions are suggested:

  • Do not collect samples during, or until three days after your menstrual period, or while you have bleeding hemorrhoids or blood in your urine.
  • Remove any cleaning or deodorizing agents from the toilet and flush twice.
  • For 3 days before the test, avoid Vitamin C tablets, iron tablets, red meat (rare, cooked and processed beef, lamb and liver), raw broccoli, cauliflower, horseradish, parsnips, radishes, turnips and melons.
  • Protect slides from heat, light and chemicals. Keep cover flap of slides closed when not in use.

What happens after the Hemoccult card is returned?
Testing the card is quick and simple. In the lab or doctors' office, the medical technician opens the flaps on the back of the card and applies a few drops of a special chemical developing solution onto each of the three stool specimens. If hemoglobin (a special blood protein found in red blood cells) is present in the stool, it reacts with the developing solution turning blue. This is an abnormal result and means that traces of blood are present. To be sure the card and developing solution are fresh and active, a quality control strip is included on the back of each card. Normally, the developing solution turns this control strip blue which means the card can be trusted.

Positive Test

The developer turns the stool specimen blue - this is an abnormal result and means that blood is present in that stool specimen.
  Negative Test

If the stool specimen does not turn blue, then no hidden blood is present. This is a normal result.

Who should do a Hemoccult test?
All adults over 50 should do this test annually even if there are no symptoms. This really should just be part of an annual checkup from your family doctor or gynecologist. Unfortunately, at present less than 25% of adult Americans are tested each year.

Who should NOT do a Hemoccult test?
Anyone with visible rectal bleeding. This test looks for hidden blood in the stool - before it is visible to the naked eye. If an individual has visible blood in the stool, there is no reason to do a Hemoccult test. You already know that bleeding is present and needs to be evaluated.

What if it is abnormal (POSITIVE)?
Don't panic! A positive Hemoccult test (one that shows blood) does not diagnose cancer. It simply means that there is blood in the stool that is not supposed to be there. There are many possible causes for blood in the stool which have nothing to do with colon cancer such as hemorrhoids, fissures, ulcers, and, as in the above example, colon polyps. The important point is that when a Hemoccult test is positive for occult blood, you must see your doctor for further testing to determine the cause. Most adults who have an abnormal stool Hemoccult test will be referred to a gastroenterologist for further evaluation. As in Tina's case, this will usually include an examination of the colon, or colonoscopy.

What if it is normal (NEGATIVE)?
That sounds reassuring, but perhaps falsely so. The Hemoccult test is a test for blood, not cancer. It is very sensitive for finding small traces of blood in the stool when present. But, you should know that most colon cancers and polyps bleed intermittently. They may lose a small amount of blood one day and not bleed again for several days. Some don't bleed at all - especially in early curable stages. So, a normal (NEGATIVE) stool Hemoccult test misses about 60% of colon polyps and 40% of colon cancers. Not very reassuring. This test is really a screening test that has some significance only if abnormal (POSITIVE). It is meant to be just a part of an overall program of colon cancer prevention, and must be supplemented with periodic direct examinations of the colon which are more accurate.

Screening colonoscopy
Because of its limited accuracy, the Hemoccult test should not be relied upon as the sole screening method. It is best combined with a periodic direct examination of the colon such as a colonoscopy. For the average adult with no symptoms, a good screening regimen would be a full colonoscopy every 10 years beginning at age 50 combined with an annual 3-day stool Hemoccult card test. High-risk individuals or those with symptoms need to be seen sooner. The colonoscopy is done by a gastroenterologist who has received special training. The family doctor or gynecologist usually orders the Hemoccult test.

Do you still need this test if you have had a colonoscopy?
Because of the higher accuracy of colonoscopy, the stool Hemoccult test becomes somewhat less valuable in patients who have periodic colonoscopy examinations. However, the test is quick, inexpensive, and non-invasive. Since colonoscopy only examines the large intestine or colon, it is possible that a Hemoccult test might detect a problem in the upper digestive tract (stomach or small intestine) - such as an ulcer. Therefore, most family doctors suggest that all of their patients over age 50 complete a 3-day stool Hemoccult card test each year - even if they have periodic colonoscopy exams.

The Hemoccult test is a simple test that can be done in the privacy of your own home. It is not a test for colon cancer, but detects hidden (occult) blood in the stool before it becomes visible. A normal test should not be reassuring since it misses over half of the colon cancers and polyps. It is not meant to be used alone, but must be part of a comprehensive colon cancer screening program which include other screening exams. A positive test should not cause panic, but must be further investigated to determine the source of bleeding. Only diagnostic testing from a physician can determine the cause of the bleeding. Used correctly, the stool Hemoccult test can be an important aid in preventing colon cancer or detecting it at a early curable stage. If you have further questions, discuss them with your doctor.

Removing Tina's Polyp

This is a photo taken during Tina's colonoscopy examination. This polyp was found on the right side of her colon about four feet inside the rectum. You can clearly see the stalk or "stem" beneath the inflamed head. Polyps that have a visible stalk are termed "pedunculated." The head is quite fragile and bleeds slightly with manipulation. This tiny amount of bleeding was detected in Tina's Hemoccult stool test. The subsequent biopsy showed this polyp to be very close to cancer, but not quite malignant. By taking the time to do this simple test, Tina added years to her life. During Tina's colonoscopy, Dr. Fusco used an electrocautery wire snare to encircle the stalk of the polyp. Under computerized control, the wire snare simultaneously cauterized the blood vessels to prevent bleeding and completely severed the stalk. The head of the polyp was retrieved in a small mesh basket and sent to the lab for biopsy. In this photo, you can see the portion of the stalk left behind after the polyp was removed. Over time, this residual stalk will simply wither away, like an old tree stump. It does not grow back. Another potential colon cancer was prevented...

Useful Digestive Links
Functional GI Disorders
Crohns and Colitis
Liver Foundation
Celiac Society
H. pylori Foundation
Ostomy Association
Amer Gastro Assoc
Gastro Endoscopy
Amer Cancer Society
Tufts Nutrition
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