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Frequently Asked Questions

Topics
Risks
Symptoms
Screening
Polyps
Prevention

If you have additional questions, call 866-305-ASGE

Risks

Who gets colorectal cancer?

Anyone can get colorectal cancer (CRC). CRC is the third most commonly diagnosed cancer and the second most common cause of cancer death in the United States, with about 145,290 new diagnosed cases and 56,290 deaths expected in 2005. When men and women are considered separately, CRC is the third most common cause of cancer death in each sex.

Does food intolerance or lactose intolerance increase your risk for colon or rectal cancer?

Very little hard data exists that consumption of lactose products or that lactose intolerance is a risk factor for colorectal cancer. However, much new literature suggests that probiotic therapy is healthy and that microflora of the colon may be altered by dietary dairy products so that the risk for colon cancer is lessened.

Is there a correlation between the length of your colon and colon cancer?

No, there is no known correlation. Cancer is at least as common in men as women, but women tend to have longer colons.

Is there a connection between stomach cancer and colorectal cancer?

There is no association between stomach (gastric) cancer and colorectal cancer, except in individuals with hereditary non-polyposis colorectal cancer (HNPCC). This is a rare genetic syndrome in which affected individuals are at risk of colorectal cancer, as well as other cancers including gastric cancer, at a young age. Individuals with a strong family history (three or more affected relatives spanning two generations with at least one affected relative under age 50) of colorectal cancer, or colorectal cancer and endometrial (uterus) cancer, may have this syndrome and may warrant genetic testing and/or screening with colonoscopy. Patients with familial polyposis also have an increased risk of gastric cancer. A personal or family history of stomach cancer should not be confused with colorectal cancer.

Is Irritable Bowel Syndrome a risk factor for developing colorectal cancer?

Irritable bowel syndrome (IBS) is a chronic functional problem of the gut usually characterized by patterns of diarrhea and loose stools alternating with constipation. IBS may also be associated with abdominal cramping and pain. IBS is not associated with an increased risk of developing colorectal cancer. Patients with IBS have normal life expectancies but should follow the recommended screening guidelines appropriate to their population. If your IBS symptoms change from their usual behavior or regular pattern, or if you see blood in your stool, notify your physician and gastroenterologist.

Can young people get colorectal cancer?

If there is no family history and if the person is under 30, should they be concerned about getting colorectal cancer? In general, it is very uncommon for young people to get colorectal cancer. However, there are two well recognized hereditary syndromes in which cancer can develop in young people. The first is Familial adenomatous polyposis (FAP). This is a disease in which affected people develop hundreds to thousands of precancerous polyps in the colon. Unless the colon is removed, 100 percent of these patients will get colorectal cancer, usually by their late 30's. The disease is inherited directly from an affected parent (autosomal dominant inheritance), and the average age for polyp development in this syndrome is the mid-teens.

If a family is known to have FAP, the affected parent and at-risk children may be screened for a gene mutation with a genetic test. Children who do not have genetic tests should start having sigmoidoscopies or colonoscopies at about 10 or 12 years old and every 6 to 12 months to look for polyps. Once numerous polyps start developing, surgery is planned. The good news about this disease is that the surgical options are very good and now the colon can often be removed by a laparoscopic approach called cholostomy. The bowel is put directly back together and no bag is necessary. People move their bowels normally.

The other well-recognized, inherited disorder is hereditary non-polyposis colorectal cancer (HNPCC). In this syndrome cancers also occur early and develop from polyps. The disease presents at a later age, too. The standard recommendation is colonoscopy in at-risk children of affected families beginning at age 25 and repeated every two years. Genetic testing may also be helpful.

So, there are specific recommendations for children in families with high rates of colorectal cancer. But the specific syndrome must be known. It is very important for children from families like these to be seen by experts who have experience with these syndromes and in institutions where genetic counseling and testing services are available.

It is possible, although quite rare, for sporadic colon cancer to occur in young people outside of those affected by FAP or HNPCC.

Symptoms

What are early symptoms of this type of cancer?

Colorectal cancer can be associated with unexplained weight loss, change in bowel habits-either constipation or diarrhea-unexplained anemia (low blood count), visible blood in the stool, hidden blood in the stool (found with a fecal occult blood test), and unexplained or sustained abdominal pain. It is also important to remember that colon cancer may not be associated with any symptoms. That is why early detection through screening is so important.

Is it possible to have blood in your stool, but not have colon cancer?

Yes. Hemorrhoids, anal fissures or tears, infections of the colon (infectious diarrhea), inflammatory bowel disease (ulcerative colitis or Crohn's colitis), colonic diverticula and abnormal blood vessels (arteriovenous malformations or angiodysplasia) may all be associated with bleeding from the rectum or colon. Blood in the stool may also occur from lesions in the stomach and small intestine such as peptic ulcer disease, angiodysplasia and Crohn's disease of the small intestine. Rectal bleeding of any amount or blood in or on the stool is never normal and should not be ignored, as some causes of rectal bleeding and blood in the stool (colon cancer) are more serious than others. Speak with your gastroenterologist about any rectal bleeding and schedule a colonoscopy to get the bleeding properly checked out.

Are intestinal obstructions an early symptom of colon cancer?

Colonic obstruction is a late symptom of colon cancer. It occurs when the tumor has grown so large that it blocks the bowel. When it occurs, urgent surgery is often required. Screening for colon cancer with colonoscopy can detect tumors long before they cause symptoms, let alone serious complications like obstruction. Obstruction may also be the symptom of something else.

Is a palpable lump in the side a symptom of colon cancer? Or is it only found as a polyp inside and can not be felt?

A palpable lump in the abdomen can be a symptom of colon cancer, but it could also be a symptom of other conditions. Your doctor would be able to examine you and give you a more personalized opinion. A polyp inside the colon cannot be felt from the outside. Polyps are found by looking inside the colon with various procedures: a sigmoidoscopy (which only looks at a portion of the colon); a colonoscopy (which can look at the whole colon); or a Virtual Colonoscopy or CT colonography (which is an x-ray technique).

Colonoscopy is considered the gold standard test for this condition and offers the physician both diagnostic and therapeutic capabilities.

Screening

Who should be screened?

Colorectal cancer screening should be a part of routine healthcare for people over the age of 50. People at higher risk for colorectal cancer should be screened earlier. These people should discuss colorectal cancer screening with their gastroenterologist to determine the right plan for them. The bottom line is, screening saves lives. Colorectal cancers almost always develop from precancerous polyps (abnormal growths) in the colon or rectum. Screening tests can find polyps so that they can be removed before they turn into cancer. Screening tests also can find colorectal cancer early, when treatment works best and the chance for a full recovery is very high. Having regular screening tests beginning at age 50 could save your life.

What is the best colon cancer screening test?

Colonoscopy is the only method that has a high sensitivity for all polyps, small and large, that can remove them at the time of the procedure. CT colonography or virtual colonoscopy (VC) is not endorsed by ASGE or the American Cancer Society because it can miss small or flat lesions. If an abnormality is seen during VC, a colonoscopic examination will still be needed to verify the finding or for polyp removal. Other, newer screening procedures include testing for abnormal DNA in the stool and the combination of a flexible sigmoidoscopy and a barium enema, which is suggested if colonoscopy is not available. However, for the removal of polyps, there is only one procedure that is currently useful, and that is colonoscopy.

Are colorectal screening tests done by your general practitioner or should they be done by gastroenterologists or other experts?

There are several types of colorectal cancer screening tests. Fecal occult blood tests are usually provided by your general practitioner for you to take home and then return to the laboratory for development and analysis. Flexible sigmoidoscopy, which evaluates the lower 1/3 of the colon with an endoscope, is performed by some but not all general practitioners. Colonoscopy is a more extensive endoscopic evaluation of the entire length of the colon and is done by gastroenterologists or other gastrointestinal specialists. Colonoscopy is considered the gold standard procedure for colon cancer screening by the American Cancer Society and many more professional organizations, and it is highly recommended that your general practitioner refer you to a Board Certified gastroenterologist or endoscopist to have the test done. You can locate an expert ASGE member here.

Can a PET scan be used for colon cancer detection instead of a colonoscopy?

PET scanning is still at an early stage of development in the detection and staging of gastrointestinal tumors and is not replacing colonoscopy for diagnosing colon cancer.

How many people are being screened for colorectal cancer?

Unfortunately, screening rates are low. In a recent survey of Americans over 50 conducted by the Centers for Disease Control (CDC), only 41% reported having had either an FOBT (the take-home stool card test) or a partial colon exam (by sigmoidoscopy) within the time intervals recommended by major professional groups such as ASGE. This number falls far short of the 86% of women who were screened for breast cancer.

Some reasons for low colorectal cancer screening rates include:

Polyps

What causes a polyp to form?

The exact causes of polyps are uncertain, but they appear to be caused by both inherited and lifestyle factors. Genetic factors may determine a person's susceptibility to the disease, whereas dietary and other lifestyle factors may determine which individuals at risk actually go on to form polyps (and later cancers). Diets high in fat and low in fruits and vegetables may increase the risk of polyps. Cigarette smoking, a sedentary lifestyle, and obesity may also increase the risk.

How can you prevent polyps from forming?

Few studies have been able to show that modifying lifestyle can greatly reduce the risk of colon polyps or cancer. However, reducing dietary fat, increasing fiber, ensuring adequate vitamin and micro-nutrient intake, and exercise may improve general health. Studies have shown that getting adequate calcium may reduce the risk of polyps.

If the polyp is removed, does that mean I am cured?

Removal of a benign polyp does prevent a cancer from developing at that one location, but the patient is likely to develop polyps at other locations. Close follow up is indicated for these patients.

Can polyps "fall off" or take care of themselves without having them removed?

Polyps have a slow growth rate and studies show polyps that are 10 mm or less have a fairly stable size over a three-year interval. A true polyp will never "fall off" or take care of itself on its own.

Is it possible to have colon or rectal cancer without having polyps?

Colorectal cancer can occur without polyps, but it is an uncommon event. Individuals with long-standing inflammatory bowel diseases, such as chronic ulcerative colitis and Crohn's colitis, are at increased risk for developing colorectal cancer that occurs in the absence of polyps.

However, colorectal cancer associated with inflammatory bowel disease accounts for less than 1 percent of all colorectal cancers diagnosed in the United States each year. There are also reports that suggest some tiny colon cancers may arise in flat colon tissue which is either entirely normal or contains a small flat area of adenomatous (precancerous) tissue. This type of colorectal cancer is the exception to the rule. The vast majority of colorectal cancers arise from pre-existing adenomatous (precancerous) polyps.

Prevention

What foods or what diet should I follow to prevent colorectal cancer from occurring? Are there any foods that actually cause colorectal cancer?

There are no foods that cause colorectal cancer. However, studies of different populations have identified associations that may affect your risk of developing colorectal cancer, or the precancerous lesions called polyps. There appears to be a slightly increased risk of developing colorectal cancer in countries with higher red meat or non-dairy (meat-associated) fat intake. For example, the U.S. and Canada have much higher rates of colorectal cancer than countries like Japan or Nigeria, where meat and fat consumption are lower. Similarly, there has been an association with decreased rates of colorectal cancer and increased fiber intake. Recent studies have questioned this association, but in general we recommend a diet high in vegetable fiber and low in fat and moderate to low in red meat. Finally, calcium and folic acid appear to have protective effects in the colon. There remain many unanswered questions in this area. No matter what your dietary intake is, don't forget to ask your doctor about the appropriate screening test to identify polyps and early cancers!

Can flax seed or green tea prevent colorectal cancer?

Green vegetables, which are rich in the antioxidant vitamins C, E, and beta-carotene and are a good source of dietary fiber, seem to provide some protection against colorectal cancer. There is an explosion of literature looking at the effect of green tea and colon cancer. Tea catechins and related polyphenols may have an inhibitory effect on colon cancer. Grape juice may have a similar inhibitory effect. Clinical trials are needed to determine true efficacy.

Does fiber play a protective role in colorectal cancer?

The question of whether fiber plays a protective role against colorectal cancer has become quite controversial. Early studies suggested that fiber is indeed protective, whereas more recent and highly publicized studies find no protective effect. Pending additional studies that may resolve this controversy, a high fiber diet is recommended because of its overall nutritional value and because it promotes good bowel function. Furthermore, fiber is also beneficial for individuals with diabetes, heart disease, hypertension and a variety of other medical conditions.