| What is colorectal cancer? |
Colorectal cancer, which includes cancers of both the colon and the rectum, is the second-leading cause of cancer-related deaths in the United States. Only lung cancer claims more lives. Each year, approximately 155,000 Americans are diagnosed with colorectal cancer and 50,000 die.
Colon and rectal cancers develop in your large intestine, the lower part of your intestinal tract. Most begin as small, noncancerous (benign) clumps of cells called adenomatous polyps. Over time some of these polyps become cancerous.
Polyps may be small and produce few, if any, symptoms, so it's important to get regular screening tests to help prevent colorectal cancer. If symptoms of cancer do appear, they may include a change in bowel habits, blood in your stool, persistent cramping, gas or abdominal pain.
Still, much of the news about colorectal cancer is good. Screening tests, along with a few simple changes in your diet and lifestyle, can dramatically reduce your overall risk of developing the disease. And if polyps and early-stage cancers are found and removed before they produce symptoms, you'll likely make a full recovery.
Your chances of beating cancer increase significantly with screening and early detection. By the time symptoms develop, it may be too late for a full recovery.
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| Signs and symptoms |
Like many people with colorectal cancer, you may have no symptoms in the early stages of the disease. When symptoms appear, they will likely vary, depending on the cancer's size and location in your large intestine. In some cases, your symptoms may result from a condition other than cancer, such as inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and sometimes diverticulosis or diverticulitis. Like colorectal cancer, these conditions can be treated.
See your doctor if you experience any of the following symptoms for more than 2 weeks:
- A change in your bowel habits, including diarrhea or constipation or a change in your stool's
consistency
- Narrow, pencil-thin stools
- Rectal bleeding or blood in your stool on more than one occasion
- Persistent abdominal discomfort, such as cramps, gas or pain
- A feeling that your bowel doesn't empty completely
Normally, hemorrhoids don't bleed consistently over a period of weeks. If your bleeding is prolonged, be sure to tell your doctor.
In addition, certain foods, such as beets or red licorice, can turn your stools red. Iron supplements and some antidiarrheal medications (Pepto Bismol is one example) may make stools black. Still, it's best to have any sign of blood or change in your stools checked promptly by your doctor.
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| Causes |
Cancer affects your cells, the basic units of life. Healthy cells grow and divide in an elegant and orderly way to keep your body functioning normally. But sometimes this growth gets out of control — cells continue dividing even when new cells aren't needed. In the colon and rectum, this exaggerated growth may cause pre-cancerous polyps (adenomas) to form in the lining of your intestine. Over a long period of time — spanning up to several years — some of these polyps may become cancerous. In later stages of the disease, cancerous polyps may penetrate the colon walls and spread (metastasize) to nearby lymph nodes or other organs.
Polyps can occur anywhere in your large intestine, the muscular tube that forms the last part of your gastrointestinal (GI) tract. The colon comprises the upper 4 to 6 feet of your large intestine, and the rectum makes up the lower 8 to 10 inches. Your colon absorbs water, salt and other minerals from food and stores waste until it's eliminated from your body.
Polyps are either mushroom-shaped or flat and may be large or small. Large or flat polyps are more likely to become cancerous than mushroom-shaped or small ones are. There are also several different types of colon polyps. Among the most common are:
- Adenomas. These polyps have the potential to become cancerous and are usually removed
during screening tests such as flexible sigmoidoscopy or colonoscopy.
- Hyperplastic. Often less than 1/4-inch in diameter, these polyps are rarely, if ever, a
risk factor of colorectal cancer.
- Inflammatory. These polyps may follow a bout of ulcerative colitis. Although the polyps themselves are not a significant risk, having ulcerative colitis increases your overall risk of colon cancer.
Although no one knows exactly what triggers abnormal cell growth, researchers have identified a number of factors that may contribute to the formation of colorectal polyps. The most important are inflammatory bowel disease, heredity and age. Other contributing factors include a high-fat diet, smoking and alcohol, a sedentary lifestyle, and possibly a lack of dietary fiber.
| Risk factors |
Age is one of the greatest risk factors for colorectal cancer — about 90 percent of people with the disease are older than age 50. Your risk generally starts increasing around age 40, and the average age at diagnosis is 62. Nearly 6 percent of people between the ages of 75 to 80 have had colorectal cancer at some point in life.
At the same time, nearly 10 percent of cases occur in men and women in their 30s or even younger. Unfortunately, no one is too young to develop colorectal cancer. This is especially true if other factors put you at a higher risk, such as:
- 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 colorectal cancer if you have a parent,
sibling or child with the disease. If many family members have colon or rectal cancer, your risk is
even greater. In some cases this connection isn't hereditary or genetic. Instead, cancers within the
same family may result from shared exposure to an environmental carcinogen or from diet or lifestyle
factors.
Familial adenomatous polyposis (FAP) is a rare hereditary disorder that causes you to develop hundreds, even thousands, of polyps in the lining of your colon and often in your upper intestine, beginning in your teenage years. If these go untreated, you'll likely develop colon cancer by age 40. In most cases, genetic testing can help determine if you're at risk of FAP.
Gardner's syndrome, a variant of FAP, is a condition that causes polyps to develop throughout your colon andupper 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).
Hereditary non-polyposis colorectal cancer (HNPCC) is another hereditary disorder that can put you at high risk of developing colon or rectal cancer. Unlike other disorders, however, you may have relatively few polyps.
If you're Jewish and of eastern European descent, you may have an inherited tendency to develop colorectal cancer. This is particularly true of Ashkenazi Jews. - Sex and race. In the United States men are at higher risk of colon cancer than are women,
and blacks have a greater risk than other racial groups do. Between 1973 and 1992, colon cancer
increased by 40 percent among black men and 16 percent among black women. But since the incidence of
colon cancer is far less in Africa than the rest of the world, the risk appears to be associated with
living in an industrialized nation, rather than with race per se.
- Diet. Researchers have long believed that eating a low-fiber diet — a diet that doesn't
include many fruits, vegetables or whole grains — greatly increases your risk of colon cancer. This
belief was bolstered by results of a study released in June 2001. Known as the European Prospective
Investigation of Cancer and Nutrition (EPIC), the study is the largest to look at the relationship
between diet and cancer. After examining 400,000 people, the study found that a high-fiber diet can
decrease the risk of colorectal cancer by as much as 40 percent. Two other studies, published in the
April 20, 2001, issue of the New England Journal of Medicine, did not find that a high-fiber
diet prevented the recurrence of colon polyps. Still, research on populations worldwide confirms that
people whose diets include plenty of fresh fruits and vegetables have less cancer than people whose
diets don't include these foods. It's likely that fruits and vegetables contain factors in addition
to fiber that help protect against colon cancer. Even so, fiber itself has a number of other health
benefits.
A diet high in fats, especially the saturated fats found in red meat, butter, dairy foods, and coconut and palm oils, seems to increase your risk of colon cancer as well as your risk of heart disease. To decrease your risk, limit the total amount of fat you eat to 30 percent of your calories each day. No more than 10 percent of fat should be saturated. - Smoking and alcohol. Smoking seems to increase your risk of colon cancer. Drinking alcohol
in excess also may increase your risk. The combination of smoking and excessive drinking makes it
even more likely you'll develop colon cancer.
- A sedentary lifestyle. If you're inactive, you're more likely to develop colon cancer, although not rectal cancer. This may be because when you're inactive, waste stays in your colon longer. Getting regular physical activity may actually cut your risk of colon cancer in half.
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| When to seek medical advice |
If you notice any symptoms of colon cancer, see your doctor right away. Keep in mind that colorectal cancer can strike younger as well as older people. If you're at high risk, don't wait until symptoms appear. See your doctor for regular screenings.
The American Cancer Society recommends colorectal screenings beginning at age 50 and more frequent or earlier screening if you have other risk factors, such as a family history of the disease. If you don't have other risk factors, Mayo Clinic physicians generally recommend colon cancer screening every 3 to 5 years, beginning at age 50.
Medicare has expanded its coverage of screening procedures. If you're over age 50 and have Medicare benefits, Medicare will cover annual fecal occult blood tests and sigmoidoscopy or barium enema X-ray every 4 years. If you're at high risk of colorectal cancer, you'll be covered for colonoscopy or barium enema every 2 years.
| Screening and diagnosis |
Most, if not all, colon cancers develop from polyps. Screening is extremely important for detecting polyps before they become cancerous. It can also help find colorectal cancer in its early stages when you have a good chance for recovery.
Like many people, you may be embarrassed by the screening procedures, worried about discomfort or afraid of the results. Try not to let these concerns stand in your way. Most procedures are only moderately uncomfortable, and working with a doctor you like and trust should help ease your embarrassment. If you question the results of your screening, ask for a second opinion. Keep in mind, however, that risks are associated with the more invasive screening procedures.
Common screening and diagnostic procedures include the following:
- Digital rectal exam. In this simple office exam, your doctor uses a gloved finger to check
the first few inches of your rectum for polyps. Although safe and painless, the exam is limited to
your lower rectum and can't detect problems with your upper rectum and colon. In addition, it's
difficult for your doctor to feel small polyps.
- Fecal occult (hidden) blood test. This 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 sample at home. You then return it to a lab or your doctor's office to be checked. The problem is
that not all cancers bleed, and those that do often bleed intermittently. Furthermore, most polyps
don't bleed. This can result in a negative test result, even though you may have 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.
- Flexible sigmoidoscopy. In this test, your doctor uses a slender, lighted tube to examine
your rectum and sigmoid — approximately the last 2 feet of your colon. Nearly half of all colon
cancers are found in this area. The test usually takes just a few minutes. It can sometimes be
somewhat uncomfortable, and there's a slight risk of perforating the colon wall.
- Barium enema. 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 an enema form.
Sometimes, air is also added. 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. This test
typically takes about 20 minutes and can be somewhat uncomfortable. There's also a slight risk of
perforating the colon wall. A flexible sigmoidoscopy is often done in addition to the barium enema to
aid in detecting small polyps that a barium enema X-ray may miss, especially in the rectosigmoid
area.
- Colonoscopy. This procedure is the most sensitive test for colorectal cancer and polyps.
Recent studies have shown it is better at detecting polyps than barium enema X-ray alone. Colonoscopy
is similar to flexible sigmoidoscopy, but 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. If any polyps are found during the exam, your doctor may remove them immediately or take
tissue samples (biopsies) for analysis. And if you have adenomatous polyps, especially those larger
than .5 centimeters in diameter, you'll need careful screening in the future.
A colonoscopy takes about a half-hour. You may receive a mild sedative to make you more comfortable. Major risks of diagnostic colonoscopy include hemorrhage and perforation of the colon wall. But these risks are rare. Complications may be somewhat more frequent when polyps are removed. - Genetic testing. 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, but it's 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. Still, you'll also want to consider
the psychological impact of what the test may reveal. Knowing you may develop cancer will affect not
only your own life, but the lives of everyone close to you. Genetic testing for children is even more
complex and problematic. It's best if you discuss all of the ramifications of genetic testing with
your doctor or a medical geneticist.
- New technologies. In the near future, new technologies, such as virtual colonoscopy, may
make colon screening safer, more comfortable and less invasive. In virtual colonoscopy, you have a
2-minute computerized tomography scan, a highly sensitive X-ray of your colon. Then, using computer
imaging, your doctor rotates this X-ray in order to view every part of your colon without actually
going inside. Before the scan, your intestine is cleared of any stool, but researchers are looking
into whether the scan can be done successfully without the usual bowel preparation. Although virtual
colonoscopy potentially is a tremendous step forward, it's not as accurate as regular colonoscopy,
and doesn't allow your doctor to remove polyps or take tissue samples. This test is also not widely
available at the present time.
Another new test checks a stool sample for DNA from abnormal cells. In preliminary studies, the test has proved to be so accurate it may eventually eliminate the need for more invasive examinations such as colonoscopy. A 3-year clinical trial of this test by the National Cancer Institute is under way.
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| Treatment |
Surgery (colectomy) is the primary treatment for colorectal cancer. How much of your colon is removed and whether other therapies, such as radiation or chemotherapy, are an option for you depends on how far the cancer has penetrated into the wall of your bowel and whether it has spread to your lymph nodes or other parts of your body.
Surgical procedures
Surgery can eliminate colon cancer in about half of all cases. Your surgeon will remove the part of your colon that contains the cancer, along with a margin of normal tissue to help ensure that no cancer is left behind. Nearby lymph nodes are usually also removed. Your surgeon is often able to reconnect the healthy portions of your colon or rectum. But when that's not possible, you may need to have a permanent or temporary colostomy. This involves creating an opening in the wall of your abdomen for the elimination of body wastes into a special bag. Sometimes the colostomy is only temporary, allowing your colon or rectum time to heal after surgery. In some cases, however, the colostomy may be permanent.
In cases of rare, inherited syndromes, such as familial adenomatous polyposis, your whole colon and rectum may be removed. Then, in a procedure known as ileal pouch-anal anastomosis, your surgeon will likely construct a pouch from the end of your small intestine that attaches directly to your anus. This allows you to expel waste normally, although you may have several watery bowel movements a day.
If you have colon surgery, side effects may sometimes include sexual dysfunction, bladder complications, diarrhea, irregular bowel movements and a sense of urinary urgency. And if you have a permanent colostomy, you'll no doubt have many other concerns, including worry about leakage or odor from your pouch, whether you'll be able to care for yourself and what people will think of you.
If your cancer is small, localized in a polyp and in a very early stage, your surgeon may be able to remove it during a colonoscopy. Some larger polyps may be removed using laparoscopic surgery. In this procedure, your surgeon performs the operation through several tiny incisions, using small instruments with attached cameras that display your colon on a video monitor. Doctors have long believed that laparoscopic surgery allows for a quicker, less painful recovery than traditional "open" surgery. But a study reported in the Jan. 16, 2002, issue of the Journal of the American Medical Association concludes that people treated with laparoscopic surgery require only slightly less pain medication and leave the hospital just a day earlier than those who have open surgery.
If your cancer is very advanced or your health very poor, only a small portion of your colon or rectum may be removed. This isn't as effective as surgeries that remove more tissue and is mainly done to relieve blockages or bleeding. Sometimes an obstruction can be relieved by using a small, expandable tube (stent) that your surgeon inserts with a colonoscope.
Chemotherapy
Chemotherapy uses drugs to destroy cancer cells. Your doctor may recommend chemotherapy, especially if your cancer has spread to your lymph nodes. Chemotherapy is usually started about a month after surgery and continued for 6 months. If your cancer has spread too far for surgery to be effective, you may also be a candidate for chemotherapy. In some cases, chemotherapy is used along with radiation therapy to treat rectal cancer. You'll likely be given the drug 5-fluorouracil (5-FU) in combination with leucovorin, a form of the B vitamin, folic acid. Right now, these drugs are given intravenously, but oral forms are being tested in clinical trials. By combining newer drugs with drugs that have been used for years, or using drugs in new ways or at different times, doctors hope to make chemotherapy more effective and lessen the severity of side effects. Possible side effects of 5-FU include nausea and vomiting, mouth sores, suppression of the bone marrow, and diarrhea. If your doctor suggests aggressive treatment with multiple drugs, be sure you understand the side effects and risks as well as the potential benefits.
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Radiation therapy
Radiation therapy uses X-rays to kill any cancer cells that might remain after surgery or to shrink large tumors before an operation so they can be removed more easily. Radiation is usually reserved for treatment of rectal cancer. The goal of therapy is to damage the tumor without harming the surrounding tissue. If your cancer has spread through the wall of the rectum, your doctor may recommend radiation treatments in combination with chemotherapy following surgery. This may help prevent cancer from reappearing in the same place. Side effects of radiation therapy may include diarrhea, rectal bleeding and, occasionally, a risk of bowel obstruction.
Staging helps determine how well you'll do and what treatments are most appropriate for you. In both cases, the size of your tumor isn't as important as how far your cancer has spread. People undergoing surgery for colon cancer have a 5-year survival rate as high as 90 percent for some cancers that haven't spread to the lymph nodes. When cancer has spread, the survival rate drops to 65 percent or less. The stages are:
- Stage 0. Your cancer is in the earliest stage. It hasn't grown beyond the inner layer
(mucosa) of your colon or rectum.
- Stage I. Your cancer has grown through the mucosa but hasn't spread through the colon
wall.
- Stage II. Your cancer has grown through the wall of the colon or rectum but hasn't spread
to nearby lymph nodes.
- Stage III. Your cancer has spread to nearby lymph nodes but not to other parts of your
body.
- Stage IV. Your cancer has spread to distant sites, such as other organs — for instance to your liver or lung, to the membrane lining the abdominal cavity, or to an ovary.
| Prevention |
The most encouraging news about colorectal cancer is that you can greatly reduce your risk by having regular screenings using colonoscopy or barium enema and flexible sigmoidoscopy. You can also protect yourself by making a few simple changes in your diet and lifestyle. The following suggestions may help save your life:
- Eat plenty of fruits and vegetables. Fruits and vegetables contain vitamins, minerals,
fiber and antioxidants, which may protect you from cancer. Try to eat five or more 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. Also try to include legumes —
including peas and beans — and soy foods, such as tofu or soy milk, in your diet.
- Limit fat, especially saturated fat. People who eat high-fat diets have a higher rate of
colorectal cancer. Be especially careful to limit saturated fats from animal sources such as red
meat. Other foods that contain saturated fat include milk, cheese, ice cream, and coconut and palm
oils. Try to restrict your total fat intake to less than 30 percent of your daily calories, with no
more than 10 percent coming from saturated fats.
- Get recommended amounts of calcium and folic acid. New research suggests that calcium and
the B vitamin, folic acid, may help reduce your risk of colorectal cancer. In fact, a study published
in the March 2002 issue of Cancer Epidemiology, Biomarkers and Prevention found that people with a
family history of colon cancer could reduce their risk by limiting alcohol consumption and upping
their intake of folic acid to 400 micrograms a day.
Good food sources of calcium include skim or low-fat milk and other dairy products, broccoli, kale and canned salmon with the bones. Folic acid is found in dark leafy greens such as spinach, and in pinto, kidney and navy beans, some nuts and seeds, and fortified cereals. Most multiple vitamins also contain both calcium and folic acid. Eating foods rich in calcium and folic acid can have added benefits for women. If you're pregnant, or think you may become pregnant, getting enough folic acid in your diet reduces the risk of certain birth defects. Recent studies also suggest that folic acid can reduce a risk factor for heart disease in postmenopausal women. Among its many other benefits, calcium helps prevent osteoporosis. - Limit alcohol consumption. Consuming moderate to heavy amounts of alcohol — more than one
drink a day for women and two for men — increases your risk of colon cancer. This is particularly
true if you have a close relative, such as a parent, child or sibling, with the disease. A drink is
considered to be a 4- to 5-ounce glass of wine, a 12-ounce can of beer, or a 1.5-ounce shot of
80-proof liquor. Studies show that curbing alcohol consumption can reduce your risk, even if colon
cancer runs in your family.
- Stop smoking. Smoking can increase your risk of both colon and lung cancer. Talk to your
doctor about ways to quit that may 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 cut your colon cancer
risk in half. Exercise stimulates movement through your bowel and reduces the time your colon is
exposed to harmful substances that may cause cancer. Try to get at least 30 minutes of exercise on
most days. If you've been inactive, start slowly and build up gradually to 30 minutes. Also, talk to
your doctor before starting any exercise program.
- Consider hormone replacement therapy. If you're a woman past menopause, hormone replacement therapy (HRT) may reduce your risk of colorectal cancer. Women who use HRT have a somewhat lower risk of colorectal cancer than women who don't use HRT. But not all effects of HRT are positive. Taking HRT as a combination therapy — estrogen plus progestin — can result in serious side effects and health risks. Work with your doctor to discuss the options and decide what's best for you.
| Coping skills |
A diagnosis of cancer can be extremely challenging. Even when a full recovery is likely, you may worry about a recurrence of the disease. But no matter what your concerns or prognosis, you're not alone. Here are some strategies and resources that may make dealing with cancer easier:
- Know what to expect. Find out everything you can about your cancer — the type, stage, your
treatment options and their side effects. The more you know, the more active you can be in your own
care. In addition to talking with your doctor, look for information in your local library and on
reliable Web sites on the Internet. The National Cancer Institute will answer questions from the
public. You can reach them at 800-4-cancer (800-422-6237). Or contact the American Cancer Society
(ACS) at 800-227-2345. Among the many services the ACS offers is a support program for people with
colostomies.
- Be proactive. Although you may feel tired and discouraged, don't let others — including
your family or your doctor — make important decisions for you. It's vital that you take an active
role in your treatment.
- Maintain a strong support system. A growing number of studies show that strong
relationships are crucial for surviving cancer. Although friends and family can be your best allies,
they sometimes may have trouble dealing with your illness. If so, the concern and understanding of a
formal support group or other cancer survivors can be especially helpful. Although support groups
aren't for everyone, they can be a good source for practical information. You may also find you
develop deep and lasting bonds with people who are going through the same things you are. There are
also support groups for the families of cancer survivors.
- Set reasonable goals. Having goals helps you feel in control and can give you a sense of
purpose. But don't choose goals you can't possibly reach. You may not be able work a 50-hour week,
for example, but you may be able work at least half-time. In fact, many people find that continuing
to work can be helpful.
- Take time for yourself. Eating well, relaxing and getting enough rest can help combat the
stress and fatigue of cancer. Also, plan ahead for the down times when you may need to rest more or
limit what you do.
- Look for a connection to something beyond yourself. Having a strong faith or a sense of something greater than yourself seems to be a factor in surviving cancer.