Filed under: Digestive Health
A colon polyp is a small clump of cells that forms on the lining of the
colon. Although most colon polyps are harmless, some become cancerous
Anyone can develop colon polyps. But you're at higher risk if you're 50
or older, are overweight or a smoker, eat a high-fat, low-fiber diet, or
have a personal or family history of colon polyps or colon cancer.
Usually colon polyps don't cause symptoms. That's why experts recommend
regular screening. Colon polyps that are found in the early stages
usually can be removed safely and completely. Screening helps prevent
colon cancer, a common disease that's often fatal when it's found in
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Colon polyps range from smaller than a pea to golf ball sized. Small
polyps aren't likely to cause problems. You might not know you have one
until your doctor finds it during an examination of your bowel.
Sometimes, however, you may have signs and symptoms such as:
* Rectal bleeding. You might notice bright red blood on toilet paper
after you've had a bowel movement. Although this may be a sign of colon
polyps or colon cancer, rectal bleeding can indicate other conditions,
such as hemorrhoids or minor tears (fissures) in your anus. You should
discuss any rectal bleeding with your doctor.
* Blood in your stool. Blood can show up as red streaks in your
stool or make bowel movements appear black. Still, a change in color
doesn't always indicate a problem — iron supplements and some
anti-diarrhea medications can make stools black, whereas beets and red
licorice can turn stools red.
* Constipation, diarrhea or narrowing of the stool. Although a
change in bowel habits that lasts longer than a week may indicate the
presence of a large colon polyp, it can also result from a number of
* Pain or obstruction. Sometimes a large colon polyp may partially
obstruct your bowel, leading to crampy abdominal pain, nausea, vomiting
and severe constipation.
When to see a doctor
See your doctor if you notice the following symptoms.
* Abdominal pain
* Blood in your stool
* A change in your bowel habits that lasts longer than a week
You should be screened regularly for polyps if:
* You're age 50 or older
* You have risk factors, such as a family history of colon cancer —
in some cases, high-risk individuals should begin regular screening much
earlier than age 50
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Your digestive tract stretches from your mouth to your anus. As food
travels along this 30-foot (9-meter) passageway, nutrients are broken
down into a form that can be absorbed by your body and used to build
cells and produce energy.
The last part of your digestive tract is a long muscular tube called the
large intestine. The colon is the upper 4 to 6 feet (1 to 2 meters) of
the large intestine; the rectum makes up the lower 8 to 10 inches (20 to
25 centimeters). The colon's main function is to absorb water, salt and
other minerals from colon contents. Your rectum stores waste until it's
eliminated from your body.
Why polyps form
The majority of polyps aren't cancerous (malignant). Yet like most
cancers, polyps are the result of abnormal cell growth. Healthy cells
grow and divide in an orderly way — a process that's controlled by two
broad groups of genes. Mutations in any of these genes can cause cells
to continue dividing even when new cells aren't needed. In the colon and
rectum, this unregulated growth can cause polyps to form. Over a long
period of time, some of these polyps may become malignant.
Polyps can develop anywhere in your large intestine. They can be small
or large and flat (sessile) or mushroom shaped and attached to a stalk
(pedunculated). Small and mushroom-shaped polyps are much less likely to
become malignant than flat or large ones are. In general, the larger a
polyp, the greater the likelihood of cancer.
There are three main types of colon polyps:
* Adenomatous. About two-thirds of all polyps fall under this
category. Although only a small percentage of these polyps actually
become cancerous, nearly all malignant polyps are adenomatous.
* Hyperplastic. Most of the remaining polyps are hyperplastic. These
polyps occur most often in your left (descending) colon and rectum.
Usually less than 0.5 centimeters (5 millimeters) in size, they're very
* Inflammatory. These polyps may follow a bout of ulcerative colitis
or Crohn's disease of the colon. Although the polyps themselves are not
a significant threat, having ulcerative colitis or Crohn's disease of
the colon increases your overall risk of colon cancer.
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Expand Arrow DownRisk factors
A number of factors may contribute to the formation of colon polyps and colon cancer. They include:
* Age. The great majority of people with colon cancer are 50 or older. Your risk generally starts increasing around age 40.
* Inflammatory intestinal conditions. Long-standing inflammatory
diseases of the colon, such as ulcerative colitis and Crohn's disease,
can increase your risk.
* Family history. You're more likely to develop colon polyps or
cancer if you have a parent, sibling or child with them. If many family
members have them, your risk is even greater. In some cases this
connection isn't hereditary or genetic. For example, cancers within the
same family may result from shared exposure to a cancer-causing
substance (carcinogen) in the environment or from similar diet or
* Smoking and alcohol. Smoking significantly increases your risk of
colon polyps and colon cancer. Smokers are 20 percent more likely to
develop colon cancer than are nonsmokers. Drinking alcohol, especially
beer, in excess also makes it more likely that you'll develop colon
polyps. If you smoke and drink, your risk increases even more.
* A sedentary lifestyle. If you're inactive, you're more likely to
develop colon cancer. This may be because when you're inactive, waste
stays in your colon longer.
* Weight. Being overweight or obese has been linked to an increased risk of several types of cancer, including colon cancer.
* Race. If you are black or an Ashkenazi Jew of Eastern European descent, you are at higher risk of developing colon cancer.
Inherited gene mutations
Another risk factor for colon polyps is genetic mutations. A small
percentage of colon cancers result from gene mutations. Some of these
cancers are autosomal dominant, meaning you need to inherit only one
defective gene from either one of your parents. If one parent has the
mutated gene, you have a 50 percent chance of inheriting the mutation.
Although inheriting a defective gene greatly increases your risk, not
everyone with a mutated gene develops cancer.
* Familial adenomatous polyposis (FAP). This is a rare, hereditary
disorder that causes you to develop hundreds, even thousands, of polyps
in the lining of your colon beginning during your teenage years. If
these go untreated, your risk of developing colon cancer is nearly 100
percent, usually before age 40. The encouraging news about FAP is that
in some cases, genetic testing can help determine whether you're at risk
of the disease. People with FAP are also at risk of cancers of the
small intestine, particularly in the duodenum.
* Gardner's syndrome. This less common syndrome is a variant of FAP.
This condition causes polyps to develop throughout your colon and small
intestine. You may also develop noncancerous tumors in other parts of
your body, including your skin (sebaceous cysts and lipomas), bone
(osteomas) and abdomen (desmoids).
* MYH-associated polyposis (MAP). This inherited condition is
similar to FAP. People with MAP often develop multiple adenomatous
polyps and colon cancer at a young age, such as in their 20s. This is a
newly discovered disease and there's more that needs to be learned about
it. Genetic testing can help determine whether you're at risk of MAP,
which is caused by mutations in the MYH gene.
* Lynch syndrome. This condition, also called hereditary
nonpolyposis colorectal cancer (HNPCC) is the most common form of
inherited colon cancer. People with Lynch syndrome tend to develop
relatively few colon polyps, but those polyps can quickly become
malignant. Or, people with Lynch syndrome may have tumors in other
organs, including the breast, stomach, small intestine, urinary tract
and ovary, as well as in the colon.
* Peutz-Jeghers syndrome (PJS). This genetic condition usually
begins with freckles developing all over the body, including the lips,
gums and feet. Then benign polyps develop throughout the intestines.
These polyps may become malignant, so people with this condition have an
increased risk of colon cancer.
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Expand Arrow DownComplications
Some polyps may become cancerous (malignant), meaning you could develop
colon cancer. The earlier polyps are removed, the less likely it is that
they will become malignant.
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Expand Arrow DownPreparing for your appointment
If it's suspected that you have colon polyps, you're likely to start by
first seeing your family doctor or a general practitioner. However, in
some cases when you call to set up an appointment, you may be referred
immediately to a gastroenterologist.
Because appointments can be brief, and because there's often a lot of
ground to cover, it's a good idea to be well prepared for your
appointment. Here's some information to help you get ready for your
appointment, and what to expect from your doctor.
What you can do
* Be aware of any pre-appointment restrictions. At the time you make
the appointment, be sure to ask if there's anything you need to do in
advance, such as restrict your diet.
* Write down any symptoms you're experiencing, including any that
may seem unrelated to the reason for which you scheduled the
* Write down key personal information, including any major stresses or recent life changes.
* Make a list of all medications, including over-the-counter
medications, as well as any vitamins or supplements, that you're taking.
* Take a family member or friend along, if possible. Sometimes it
can be difficult to absorb all the information provided during an
appointment. Someone who accompanies you may remember something that you
missed or forgot.
* Write down questions to ask your doctor.
Your time with your doctor is limited, so preparing a list of questions
ahead of time will help you make the most of your time together. List
your questions from most important to least important in case time runs
out. For colon polyps, some basic questions to ask your doctor include:
* What is likely causing my symptoms or condition?
* Are there other possible causes for my symptoms or condition?
* What kinds of tests do I need?
* What is the best course of action?
* What are the alternatives to the primary approach that you're suggesting?
* I have these other health conditions. How can I best manage them together?
* Are there any restrictions that I need to follow?
* Should I see a specialist? What will that cost, and will my insurance cover it?
* Is there a generic alternative to the medicine you're prescribing me?
* Are there any brochures or other printed material that I can take with me? What Web sites do you recommend?
* What are the chances these polyps are malignant?
* If you find a polyp, how safe is it to remove during colonoscopy?
* If you find a polyp, when will I need another colonoscopy?
In addition to the questions that you've prepared to ask your doctor,
don't hesitate to ask questions at any time that you don't understand
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to
answer them may reserve time to go over points you want to spend more
time on. Your doctor may ask:
* When did you first begin experiencing symptoms?
* Have your symptoms been continuous or occasional?
* How severe are your symptoms?
* What, if anything, seems to improve your symptoms?
* What, if anything, appears to worsen your symptoms?
* Have you or has anyone in your family had colon cancer or colon polyps?
* How much do you smoke and drink?
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Expand Arrow DownTests and diagnosis
Nearly all colon cancers develop from polyps, but the polyps grow
slowly, usually over a period of years. Screening tests play a key role
in detecting polyps before they become cancerous. These tests can also
help find colorectal cancer in its early stages, when you have a good
chance of recovery. When early-stage cancers are found and removed
during routine screening, the five-year survival rate may be as high as
Several screening methods exist — each with its own benefits and risks. Be sure to discuss these with your doctor:
Fecal occult (hidden) blood test
This noninvasive test checks a sample of your stool for blood. It can be
performed in your doctor's office, but you're usually given a kit that
explains how to take the test at home. It's important to follow the
instructions carefully, because your diet and other factors can affect
the results. You return the test kit to a lab or your doctor's office to
* Risks and benefits. Although this test is relatively easy, it's
designed to screen for cancer, not for polyps. One problem is that most
polyps don't bleed, nor do all cancers. This can result in a negative
test result, even though you may have a polyp or cancer. On the other
hand, if blood shows up in your stool, it may be the result of
hemorrhoids or an intestinal condition other than cancer. For these
reasons, many doctors recommend other screening methods instead of, or
in addition to, fecal occult blood tests. Also, even if the test is
negative, if you have seen blood in the toilet, toilet paper or stool,
you will need to go through further testing.
In this test, your doctor uses a slender, lighted tube to examine your
rectum and sigmoid — approximately the last 2 feet (61 centimeters) of
your colon. Nearly half of all colon cancers are found in this area.
* Risks and benefits. A sigmoidoscopy looks at only the last third
of your colon, and this test doesn't detect polyps elsewhere in the
large intestine. It's often combined with a barium enema to better
visualize the entire colon, or your doctor may recommend performing a
colonoscopy instead. A sigmoidoscopy can be somewhat uncomfortable.
Also, there's a slight risk of perforating the colon, but the risks are
less than they are for colonoscopy.
This diagnostic test allows your doctor to evaluate your entire large
intestine with an X-ray. Barium, a contrast dye, is placed into your
bowel in enema form. The barium fills and coats the lining of the bowel,
creating a clear silhouette of your rectum, colon and sometimes a small
portion of your small intestine. Air may also be added to provide
better contrast on the X-ray.
* Risks and benefits. Because barium enema has a higher miss rate
for colon polyps, it's not nearly as reliable as some other screening
tests. It also doesn't allow your doctor to take a biopsy during the
procedure to determine whether a polyp is cancerous. This test can be
somewhat uncomfortable because the barium and air distend your bowel.
There's also a slight risk of perforating the colon wall.
Colonoscopy is similar to flexible sigmoidoscopy. However, the
instrument used — a colonoscope, which is a long, slender tube attached
to a video camera and monitor — allows your doctor to view your entire
colon and rectum.
* Risks and benefits. This procedure is the most sensitive test for
colorectal polyps and colorectal cancer. It's better at detecting polyps
than is a barium enema X-ray alone. If any polyps are found during the
exam, your doctor may remove them immediately or take tissue samples
(biopsies) for analysis. In order to prepare for the exam, you follow
your doctor's instructions on restricting your diet and taking laxatives
to cleanse your bowel. You're likely to receive a mild sedative to make
you more comfortable. The risks of diagnostic colonoscopy include
hemorrhage and perforation of the colon wall. Complications are more
likely to occur when polyps are removed.
Computerized tomographic colonography (CTC)
Also referred to as virtual colonoscopy, this test involves a
computerized tomography scan, a highly sensitive X-ray of your colon.
Using computer imaging, your doctor rotates this X-ray in order to view
every part of your colon and rectum without actually going inside your
body. Before the scan, your large intestine is cleared of any stool, but
researchers are looking into whether the scan can be done successfully
without the usual bowel preparation.
* Risks and benefits. This newer technology may make colon screening
safer, more comfortable and less invasive. It can be done more quickly
and doesn't require sedation. However, it may not be as accurate as
regular colonoscopy. Some studies have shown it is effective, but there
are not enough data to make a good comparison between CTC and
colonoscopy. Also, this method doesn't allow your doctor to remove
polyps or take tissue samples during the procedure. If your doctor finds
polyps or wants to sample tissue, you will need a colonoscopy.
Stool DNA testing
This new colon cancer screening approach can detect cancer cells that
have shed into your stool. The malignant cells have altered DNA, and
this test can detect DNA mutations (markers) for some types of cancerous
tumors and precancerous polyps. Research is underway to increase the
test's accuracy and determine how often it should be done.
* Risks and benefits. This test is designed primarily to detect
colon cancer and not to screen for colon polyps. It is available but has
not been certified by the Food and Drug Administration.
If you have a family history of colorectal cancer, you may be a
candidate for genetic testing. This blood test may help determine if
you're at increased risk of colon or rectal cancer.
* Risks and benefits. Genetic testing is not without drawbacks. The
results can be ambiguous, and the presence of a defective gene doesn't
necessarily mean you'll develop cancer. Knowing you have a genetic
predisposition can alert you to the need for regular screening.
Treatments and drugs
Although some types of colon polyps are far more likely to become
malignant than are others, a pathologist usually must examine polyp
tissue under a microscope to determine whether it's potentially
cancerous. For that reason, your doctor is likely to remove all polyps
discovered during a bowel examination.
The great majority of polyps can be removed during colonoscopy or
sigmoidoscopy by snaring them with a wire loop that simultaneously cuts
the stalk of the polyp and cauterizes it to prevent bleeding. Some small
polyps may be cauterized or burned with an electrical current. Risks of
polyp removal (polypectomy) include bleeding and perforation of the
Polyps that are too large to snare or that can't be reached safely are
usually surgically removed — often using laparoscopic techniques. This
means your surgeon performs the operation through several small
incisions in your abdominal wall, using instruments with attached
cameras that display your colon on a video monitor. Laparoscopic surgery
may result in a faster and less painful recovery than does traditional
surgery using a single large incision. Once the section of your colon
that contains the polyp is removed, the polyp can't recur, but you have a
moderate chance of developing new polyps in other areas of your colon
in the future. For that reason, follow-up care is extremely important.
Endoscopic mucosal resection
Some specialized medical centers perform endoscopic mucosal resection
(EMR) to remove larger polyps with a colonoscope. For this newer
technique a liquid, such as saline, is injected under the polyp to
elevate and isolate the polyp from surrounding tissue. This makes it
easier to remove a larger polyp. With this procedure, you can avoid
surgery, but complication rates may be higher.
Colon and rectum removal
In cases of rare, inherited syndromes, such as familial adenomatous
polyposis (FAP), your surgeon may perform an operation to remove your
entire colon and rectum (total proctocolectomy). Then, in a procedure
known as ileal pouch-anal anastomosis, a pouch is constructed from the
end of your small intestine (ileum) that attaches directly to your anus.
This allows you to expel waste normally, although you may have several
watery bowel movements a day.
You can greatly reduce your risk of colon polyps and colorectal cancer
by having regular screenings and by making certain changes in your diet
and lifestyle. The following suggestions may help lower your risk of
colon polyps and colon cancer:
* Pay attention to calcium. Calcium can significantly protect
against colon polyps and cancers, even if you've had them before. Good
food sources of calcium include skim or low-fat milk and other dairy
products, broccoli, kale and canned salmon with the bones. Vitamin D,
which aids in the absorption of calcium, also appears to help reduce the
risk of colorectal cancer. You get vitamin D from foods such as vitamin
D-fortified milk products, liver, egg yolks and fish. Sunlight also
converts a chemical in your skin into a usable form of the vitamin. If
you don't drink milk or you avoid the sun, you may want to consider
taking both a vitamin D and a calcium supplement.
* Include plenty of fruits, vegetables and whole grains in your
diet. These foods are high in fiber, which may cut your risk of
developing colon polyps. Fruits and vegetables also contain
antioxidants, which may help prevent cancer. The American Cancer Society
recommends eating at least five servings of fruits and vegetables every
day. Look for deep green and dark yellow or orange fruits and
vegetables such as Swiss chard, bok choy, spinach, cantaloupe, mango,
acorn or butternut squash, and sweet potatoes, as well as vegetables
from the cabbage family, including broccoli, Brussels sprouts and
cauliflower. Lycopene, a nutrient found in tomatoes and other red fruits
and vegetables, such as strawberries and red bell peppers, may be a
particularly powerful anti-cancer chemical.
* Watch your fat intake. Certain types of fat can increase your risk
of colon cancer, but other types are protective. It's important to
limit saturated fats from red meat as well as processed meat such as
hotdogs, sausage or brats. Other foods that contain saturated fat
include whole milk, cheese, ice cream, and coconut and palm oils.
Restrict your total fat intake to less than 35 percent of your daily
calories, with no more than 10 percent coming from saturated fats.
Healthy fats, such as omega-3 fatty acids found in fish, walnuts and
olive oil, may protect you from cancer. Try to get most of your fat
intake from these types of foods.
* Limit alcohol consumption. Consuming moderate to heavy amounts of
alcohol — more than one drink a day for women and two for men — may
increase your risk of colon polyps and cancer. A drink is considered to
be 4 to 5 ounces (12 to 15 centiliters) of wine, 12 ounces (35
centiliters) of beer, or 1.5 ounces (4.5 centiliters) of 80-proof
liquor. Curbing alcohol consumption can reduce your risk, even if colon
cancer runs in your family.
* Stop smoking. Smoking can increase your risk of colon cancer and a
wide range of other diseases. Talk to your doctor about ways to quit
that might work for you.
* Stay physically active and maintain a healthy body weight.
Controlling your weight alone can reduce your risk of colorectal cancer.
And staying physically active may significantly cut your colon cancer
risk. The American Cancer Society recommends at least 30 minutes of
physical activity five or more days a week. Forty-five minutes or more
is even better. If you're overweight, lose weight until you're at a
healthy level and maintain it.
* Talk to your doctor about aspirin. Studies on the role of aspirin
in polyp and cancer prevention are mixed. Some studies show that regular
aspirin use can reduce your risks, but others show no benefit. Aspirin
use can increase your risk of gastrointestinal bleeding. So check with
your doctor before starting any aspirin regimen.
* Talk to your doctor about hormone therapy (HT). If you're a woman
past menopause, hormone therapy may reduce your risk of colorectal
cancer. But not all effects of HT are positive. Taking HT as a
combination therapy — estrogen plus progestin — can increase your risk
of breast cancer, dementia, heart disease, stroke and blood clots, so
it's not usually used for preventing colon polyps. Discuss your options
with your doctor. Together you can decide what's best for you.
* If you're at high risk, consider your options. If you're at risk
of familial adenomatous polyposis (FAP) because of a family history of
the disease, consider having genetic counseling. And if you've been
diagnosed with FAP, start having regular colonoscopy tests in your early
teens and discuss your options with your doctor. Your doctor may
recommend having surgery to remove your entire colon when you're in your
20s. Doctors recommend that people at risk of Lynch Syndrome begin
having regular colonoscopies around age 20.