What Is Colorectal Cancer?
Colorectal cancer is a term used to refer to cancer that starts in the colon or rectum. Colon and rectal cancers begin in the digestive system, also called the GI (gastrointestinal) system. This is where food is processed to create energy and rid the body of waste matter.

After food is chewed and swallowed, it travels down to the stomach. There it is partly broken down and sent to the small intestine. The word "small" refers to the diameter of the small intestine. The small intestine is really the longest segment of the digestive system. It is about 20 feet long.

The small intestine continues breaking down the food and absorbs most of the nutrients. The small intestine joins the large intestine (large bowel), a muscular tube about five feet long. The first part of the large bowel, called the colon, absorbs water and nutrients from the food and also serves as a storage place for waste matter. The waste matter moves from the colon into the rectum, the final 6 inches of the large bowel. From there the waste passes out of the body through the opening called the anus during a bowel movement.

The colon has 4 sections, as shown in the picture above. Cancer can start in any of the four sections or in the rectum. The wall of each of these sections (and rectum) has several layers of tissues. Cancer starts in the inner layer and can grow through some or all of the other layers. Knowing a little about these layers is helpful because the stage (extent of spread) of a cancer depends to a great degree on which of these layers it affects.

Cancer that starts in the different areas may cause different symptoms. In most cases, colon and rectum cancers develop slowly over a period of several years. We now know that most of these cancers begin as a polyp – a growth of tissue into the center of the colon or rectum. A type of polyp known as adenomacan become cancerous. Removing the polyp early may prevent it from becoming cancer.

Over 95% of colon and rectal cancers are adenocarcinomas. These are cancers of the cells that line the inside of the colon and rectum. There are some other, more rare, types of tumors of the colon and rectum, but the facts given here refer only to adenocarcinomas.

Colon and rectal cancer have many features in common and are often referred to simply as “colorectal cancer.” They are discussed together here except for the section about treatment. At that point they will be discussed separately.

What Causes Colorectal Cancer?
While we do not know the exact cause of most colorectal cancer, there are certain known risk factors. A risk factor is something that increases a person's chance of getting a disease. Some risk factors, like smoking, can be controlled. Others, such as a person's age, can't be changed. Researchers have found several risk factors that increase a person's chance of getting colorectal cancer.

Risk Factors for Colorectal Cancer
Age: Your chance of having colorectal cancer goes up after age 50. More than 9 out of 10 people found to have colorectal cancer are older than 50.

Having had colorectal cancer before: Even if a colorectal cancer has been completely removed, new cancers could start in other areas of your colon and rectum.

Having a history of polyps: Some types of polyps increase the risk of colorectal cancer, especially if they are large or if there are many of them.

Having a history of bowel disease: Two diseases called ulcerative colitis and Crohn’s disease increase the risk of colon cancer. In these diseases, the colon is inflamed over a long period of time and there may be ulcers in its lining. If you have either of these, you should start being tested at a young age and have the tests often.

Family history of colorectal cancer: If you have close relatives who have had this cancer, your risk is increased. This is especially true if the family member got the cancer before age 60. People with a family history of colorectal cancer should talk to their doctors about how often to have screening tests.

Certain family syndromes: A syndrome is a group of symptoms. For example, in some families, members tend to get a type of syndrome that involves having hundreds of polyps in their colon or rectum. Cancer often develops in one or more of these polyps.

If your doctor tells you that you have a condition that makes you or your family members more likely to get colorectal cancer, you will probably need to begin colon cancer testing at a younger age and you might think about genetic counseling.

Ethnic background: Jews of Eastern European descent (Ashkenazi Jews) have a higher rate of colon cancer.

Diet: A diet high in fat, especially fat from animal sources, can increase the risk of colorectal cancer.

Lack of exercise: People who are not active have a higher risk of colorectal cancer.

Overweight: Being very overweight increases a person's colorectal cancer risk.

Smoking: Most people know that smoking causes lung cancer, but recent studies show that smokers are 30% to 40% more likely than nonsmokers to die of colorectal cancer. And smoking increases the risk of many other cancers as well.

Alcohol: Heavy use of alcohol has been linked to colorectal cancer.

Factors that Are Less Certain
Race: African Americans are at higher risk of getting this cancer and dying from it. The reason for this is not known.

Diabetes: People with diabetes have a 30% to 40% increased chance of getting colorectal cancer. They also tend to have a higher death rate from this cancer.

Night-shift work: One study suggests that working a night shift at least 3 nights a month for at least 15 years might increase the risk of colorectal cancer in women. More research is needed.

Other cancers and their treatment: A recent report on testicular cancer survivors found that these men had a higher rate of colorectal cancer. Men who receive radiation therapy for prostate cancer have been reported to have a higher risk of rectal cancer.

The American Cancer Society and several other medical organizations recommend earlier testing for people with increased colorectal cancer risk. These recommendations differ from those for people at average risk. For more information, talk with your doctor.

Can Colorectal Cancer Be Prevented?
Even though we don't know exactly what causes colorectal cancer, there are some steps you can take to reduce your risk.

Screening tests: First, you should follow the early detection screening guidelines mentioned below to help find colon or rectal cancer. When these cancers are found and treated early, they can often be cured. Screening can also find polyps. Removing these polyps helps prevent some cancers.

People who have a history of colorectal cancer in their family should check with their doctor for advice about screening tests or other tests to find cancer early.

Diet and exercise: The American Cancer Society recommends choosing most of your foods from plant sources, eating at least 5 servings of fruits and vegetables every day and limiting the amount of high-fat foods you eat. Some studies suggest that taking a daily multivitamin containing folic acid or folate can lower colorectal cancer risk. Other studies suggest that getting more calcium can help. Getting enough exercise is important as well. The American Cancer Society recommends at least 30 minutes of physical activity on 5 or more days of the week.

Aspirin and other drugs: Aspirin appears to prevent the growth of polyps. A drug called Celebrex also reduces polyps for some people whose family members tend to develop polyps. But these medicines can have side effects. For this reason, experts do not advise the general public to take them to try to prevent colorectal cancer. If you are at high risk for colorectal cancer, talk to your doctor about what you should do.

Other factors: People with a family history of colorectal cancer may benefit from starting screening tests when they are younger and having them done more often than people without this risk factor.

How Is Colorectal Cancer Found?

Screening tests are used to look for disease in people who do not have any symptoms. In many cases, these tests can find colorectal cancers at an early stage and greatly improve the chances of successful treatment. Screening tests can also help prevent some cancers by allowing doctors to find and remove polyps that might become cancer. There are several tests used for colorectal cancer.

Stool blood test (fecal occult blood test – FOBT): This test is used to find small amounts of hidden (occult) blood in the stool. A sample of stool is tested for traces of blood. People having this test will receive a kit with instructions that explain how to take stool samples at home. The kit is then sent to a lab for testing. If the test is positive, further tests, such as a colonoscopy, will be done to pinpoint the exact cause of the bleeding.

A newer kind of stool blood test is known as FIT (fecal immunochemical test). It is very much like the FOBT but is perhaps a little easier to do and it gives a fewer number of false positive results. If it is positive, further tests will be done.

Flexible sigmoidoscopy (flex-sig): A sigmoidoscope is a slender, lighted tube about the thickness of a finger. It is placed into the lower part of the colon through the rectum. This allows the doctor to look at the inside of the rectum and part of the colon for cancer or polyps. Because the tube is only about 2 feet long, the doctor is only able to see about half of the colon. The test can be uncomfortable but it should not be painful. Before the test, you will need to take an enema to clean out the lower colon.

Colonoscopy: A colonoscope is a longer version of the sigmoidoscope. It allows the doctor to see the entire colon. If a polyp is found, the doctor may remove it. If anything else looks abnormal, a biopsy might be done. To do this, a small piece of tissue is taken out through the colonoscope. The tissue is sent to the lab to see if cancer cells are present. This test can be uncomfortable. To avoid this, you will be given medicine through a vein to make you feel relaxed and sleepy

Barium enema with air contrast: A chalky substance is used to partly fill and open up the colon. Air is then pumped in to cause the colon to expand. This allows good x-ray films to be taken. You will need to use laxatives the night before the exam and have an enema the morning of the exam.

Virtual colonoscopy: You might think of this as a super x-ray of the colon. Air is pumped into the colon to cause it to expand, and then a special CT scan is done. Right now, this test is not among those recommended by the ACS or other major medical organizations for finding colon cancer early. More studies are needed to find out if it is as good as or better than other methods of finding colon cancer early.

Colorectal Cancer Screening Guidelines
Beginning at age 50, both men and women at average risk should follow 1of the 5 screening options below:

1. yearly stool blood test (FOBT) or fecal immunochemical test (FIT)
2. flexible sigmoidoscopy every 5 years
3. yearly stool blood test plus flexible sigmoidoscopy every 5 years
Or you may have:
4. double contrast barium enema every 5 years
5. colonoscopy every 10 years

For the stool blood test, the take-home, multiple-sample method should be used.

If something abnormal is found, a colonoscopy should be done. If any polyps are found they should be removed if possible.

While a digital rectal exam (DRE) is often done as part of a regular physical exam, it should not be used as a stand-alone test for colorectal cancer. For a DRE, the doctor examines the patient’s rectum with a gloved finger.

If anything abnormal is found on any of the tests, a colonoscopy should be done.

People with certain risk factors should begin screening earlier or have screening more often. For more information, please see Colrectal Cancer Early Detection. Talk to your doctor about your own risk and when you should have screening tests

Medicare Coverage
For people on Medicare, this is what is covered:
Stool blood test (FOBT or FIT) each year for those 50 and over
Flexible sigmoidoscopy (flex-sig) every 4 years for those 50 and over at average risk
Colonoscopy every 2 years for those at high risk
Colonoscopy once every 10 years for those 50 and over at average risk
Barium enema with air contrast instead if a doctor believes that it is as good as or better than flex-sig or colonoscopy.

What would someone on Medicare expect to pay for these tests?
Stool blood test: people age 50 and older pay no coinsurance and no Part B deductible
Flex-sig: Patient pays 20% of Medicare-approved amount after the yearly Part B deductible Colonoscopy: Patient pays 20% of Medicare-approved amount after the yearly Part B deductible Barium enema: When used instead of flex-sig or colonoscopy, patient pays 20% of Medicare-approved amount after the yearly Part B deductible

How Is Colorectal Cancer Diagnosed?
Most people with early colon cancer don’t have symptoms. Symptoms usually appear with more advanced disease. If something suspicious turns up as a result of screening or if you have symptoms, you will need further tests. Symptoms of colorectal cancer include:

• a change in bowel habits such as diarrhea, constipation, or narrowing of the stool that lasts for more than a few days
• a feeling that you need to have a bowel movement that doesn't go away after doing so
• bleeding from the rectum or blood in the stool (often, though, the stool will look normal)
• cramping or steady stomach pain
• weakess and tiredness

Just because you have these symptoms does not mean you have cancer. But you need to talk to your doctor to be sure. It is also possible to have colon cancer and not have any symptoms.

If there is any reason to suspect colon or rectal cancer, the doctor will ask you questions about your symptoms and risk factors (take a medical history) and do a physical exam. Then you will need to have further tests to find out if the disease is really present and if so, to see how far it has spread. Some of these tests are the same ones that are used for screening people who do not have symptoms.

Stool blood test, flex-sig, barium enema, and colonoscopy: your doctor may do one or more of these tests. They were described earlier.

Blood tests: Your doctor will order a blood count to see if you have too few red blood cells (anemia). People with colorectal cancer often become anemic because of bleeding from the tumor. You might also have blood tests to check your liver function because colorectal cancer can spread to the liver causing problems. There are other substances (tumor markers) in the blood that can help tell how well treatment is working. But these tumor markers are not used to find cancer in people who have not had cancer and who appear to be healthy; rather, they are most often used for follow-up of people who have already been treated for colorectal cancer.

Biopsy: In a biopsy, the doctor removes a small piece of tissue. The tissue is sent to the lab where it is looked at under a microscope to see if cancer is present.

Ultrasound: Ultrasound uses sound waves to produce a picture of the inside of the body. Most people know about ultrasound because it is often used to view a baby during pregnancy. This is an easy test to have. You simply lie on a table while a kind of wand is moved over your skin.
Two special types of ultrasound might be used for people with colon or rectal cancer. In one, the instrument that gives off sound waves is placed into the rectum. In the other test, used during surgery, the instrument is placed against the surface of the liver to see if the cancer has spread there.

CT scan (computed tomography): A CT scan uses x-rays to take many pictures of the body that are then combined by a computer to give a detailed picture. A CT scan can often show whether the cancer has spread to the liver, lungs, or other organs. CT scans can also be used to help guide a biopsy needle into a tumor. CT scans take longer than regular x-rays. The patient has to lie still on a table while the CT scan is being done. A contrast "dye" may be injected or a special drink used to help outline the area being viewed.

A new way to use a CT scan is to do a "virtual colonoscopy." After stool is cleaned from the colon and the colon is filled with air, a computer can put together a picture of the inside of the colon. This method requires the same preparation as for a colonoscopy and there is some discomfort from the bowel being filled with air. If anything not normal is seen, a follow-up colonoscopy will be needed.

MRI (magnetic resonance imaging): Like CT scans, MRI displays a cross-section of the body. However, MRI uses radio waves and strong magnets instead of radiation. As with CT scans, a contrast dye may be injected, although this is used less often. MRI scans are helpful in looking at the brain and spinal cord. They take longer than CT scans and you may have to be placed inside a tube. This can feel confining and upset people with a fear of closed spaces.

Chest x-ray: This test may be done to see whether colorectal cancer has spread to the lungs.

PET scan (positron emission tomography): In this test, a type of radioactive sugar is used. The cancer cells absorb high amounts of the sugar. PET is useful when your doctor thinks the cancer has spread, but doesn't know where. PET scans are now more accurate because they can be combined with a CT scan.

Angiography: For this test, a tube is placed into a blood vessel and moved until it reaches the area to be studied. Then a dye is injected and a series of x-ray pictures is taken. When the pictures are complete, the tube is removed. Surgeons sometimes use this method to find blood vessels next to cancer that has spread to the liver. The cancer can then be removed without causing a lot of bleeding.

How Is Colorectal Cancer Treated?
The 3 main types of treatment for colorectal cancer are surgery, radiation therapy, and chemotherapy. Newer, targeted therapies called monoclonal antibodies are now being used as well. Depending on the stage of your cancer, 2 or more types of treatment may be used at the same time, or one after the other.

Feel free to take your time and think about all of the choices. You may want to get a second opinion. This can provide more information and help you feel better about the treatment plan you choose. Your chances of having a good outcome are highest in the hands of a medical team that has experience in treating colorectal cancer.

Surgery
Surgery is the main treatment for colon cancer. Usually the cancer and a length of normal colon on either side of the cancer (as well as nearby lymph nodes) are removed. The two ends of the colon are then sewn back together. For colon cancer, a colostomy (an opening in the abdomen for getting rid of body wastes) is not usually needed, although sometimes a temporary colostomy may be done.

Sometimes very early colon cancer can be removed through a colonoscope. When this is done, the doctor does not have to cut into the abdomen. Surgery for colon cancer can sometimes be done with a new approach called “laparoscopic” or “keyhole” surgery. In this method, a lighted tube and special instruments are placed inside the body through a few small incisions, rather than one large one. Keyhole surgery for colon cancer works as well as the standard approach and patients usually recover faster than they do after the usual operations.

Surgery is usually the main treatment for rectal cancer, although radiation and chemotherapy will often be given before surgery. There are several types of surgery for rectal cancer.

Some operations (polypectomy, local excision, and local transanal resection) can be done with instruments placed into the anus, without having to cut through the skin. One of these methods might be used to remove some stage I cancers that are fairly small and not too far from the anus.

For some stage I, and most stage II or III rectal cancers, other types of surgery may be done. A low anterior resection is used for cancers near the upper part of the rectum, close to where it connects with the colon. After this operation waste is eliminated in the usual way.

For cancers in the lower part of the rectum, close to its outer connection to the anus, an abdominoperineal resection is done. After this surgery, a colostomy is needed. A colostomy is an opening of the colon in the front of the abdomen. It is used for the elimination of solid body waste (feces or stool).

If the rectal cancer is growing into nearby organs, more extensive surgery is needed. In a pelvic exenteration the surgeon removes the rectum as well as nearby organs such as the bladder, prostate, or uterus if the cancer has spread to these organs. A colostomy is needed after this operation. If the bladder is removed, a urostomy (opening to collect urine) is needed.

If you have a colostomy or a urostomy, you will need help in learning how to manage it. This can be done by specially trained nurses. They will usually see you before your operation and again afterwards for more training.

Possible side effects of surgery include bleeding from the surgery, blood clots in the legs, and damage to nearby organs during the operation. Rarely, the connections between the ends of the intestine may not hold together completely and leak. If an infection occurs, it is possible that the incision might open up, causing an open wound. Later, after the surgery, you might develop what are called adhesions that could cause the bowel to become blocked.

Colorectal surgery and sex
If you are a man, an AP resection can cause you to have "dry" orgasms. That is, the feeling of pleasure will most likely still be there, but no semen is released. In some cases an AP resection may stop your erections or ability to reach orgasm. In other cases your pleasure at orgasm may become less intense. Normal aging may cause some of these changes, but surgery can increase them.

For some men, the surgery causes the semen to go backward into the bladder. If you still want to father a child, you should talk to your doctor about how the surgery will affect you and what might be done to achieve a pregnancy.

If you are a woman having a colostomy, you should not normally find any loss of sexual function. The American Cancer Society has more information for both men and women about sexuality and cancer. Please see the, "How Can I Learn More" section.

Surgery for Colorectal Cancer That Has Spread
If the colorectal cancer has spread to a few areas in the lungs, liver, ovaries, or elsewhere in the abdomen, the cancer might be cured by removing it from these areas. Or the surgery might help to extend life.

For spread to the liver, there are other methods besides surgery which might be used to destroy the cancer. These include methods to block the blood supply to the tumor or to destroy the cancer through freezing or by heating with microwaves. These methods are not meant to cure the cancer.

Radiation Therapy for Colon and Rectal Cancer
Radiation therapy is treatment with high-energy rays (such as x-rays) to kill or shrink cancer cells. The radiation may come from outside the body (external radiation) or from radioactive materials placed directly in the tumor (internal or implant radiation).

After surgery, radiation can kill small areas of cancer that may not be seen during surgery. If the size or location of a tumor makes surgery hard, radiation may be used before the surgery to shrink the tumor. Radiation can also be used to ease symptoms of advanced cancer such as intestinal blockage, bleeding, or pain.

The main use for radiation therapy in people with colon cancer is when the cancer has attached to an internal organ or the lining of the abdomen. If this happens, the doctor cannot be sure that all the cancer has been removed, and radiation therapy is used to kill the cancer cells left behind after surgery. For rectal cancer, radiation is also given to prevent the cancer from coming back in the place where it started and to treat local recurrences that are causing symptoms such as pain. Radiation is seldom used to treat metastatic colon cancer.

External radiation is most often used for people with colon or rectal cancer. Treatments are given 5 days a week for several weeks. Each treatment lasts only a few minutes and is something like having an x-ray for a broken bone.

A different approach may be used for some cases of rectal cancer. The radiation can be aimed through the anus and reaches the rectum without passing through the skin of the abdomen.

For internal radiation therapy, small pellets of radioactive material are placed next to or directly into the cancer. This method is sometimes used in treating people with rectal cancer, particularly sick or older people who would not be able to withstand surgery.

Side effects of radiation therapy for colon or rectal cancer include mild skin irritation, nausea, diarrhea, rectal or bladder irritation, or tiredness. Sexual problems may also occur in men. Side effects often go away after treatment is over. If you have these or other side effects, talk to your doctor. There are ways to reduce or relieve many of these problems.

Chemotherapy
Chemotherapy is the use of anticancer drugs injected into a vein or given by mouth. These drugs enter the bloodstream and spread throughout the body, making the treatment useful for cancers that have spread to distant organs.

Chemotherapy after surgery can increase the survival rate for patients with some stages of colorectal cancer. Chemotherapy can also help relieve symptoms of advanced cancer.

In some cases, chemotherapy drugs can be injected into an artery leading to the part of the body with the tumor. This approach is called regional chemotherapy. Since the drugs go straight to the cancer cells, there may be fewer side effects.

While chemotherapy drugs kill cancer cells, they also damage some normal cells and this can lead to side effects. These side effects will depend on the type of drugs given, the amount given, and how long treatment lasts. Side effects could include the following:

• diarrhea
• nausea and vomiting
• loss of appetite
• loss of hair
• hand and foot rashes and swelling
• mouth sores
• increased chance of infection
• bleeding or bruising after minor cuts or injuries
• fatigue

Most of the side effects go away when treatment is over. For example, hair will grow back after treatment ends, though it may look different. Anyone who has problems with side effects should talk with their doctor or nurse, as there are often ways to help.

Targeted therapies are methods that attack some part of cancer cells that make them different from normal cells. Because of this, they often cause fewer side effects than chemotherapy. Manmade proteins called monoclonal antibodies have been approved for use, along with chemotherapy drugs, against colorectal cancer.

Some cancer drugs, especially monoclonal antibodies, are very expensive. Patients on Medicare without any other insurance will need to pay for 20% of this cost.

Colorectal Cancer Survival Rates
Nine out of 10 people whose colorectal cancer is found and treated at an early stage, before it has spread, live at least five years. Once the cancer has spread to nearby organs or lymph nodes, the 5-year survival rate goes down. The 5-year survival rate is the percentage of patients who are alive 5 years after diagnosis (leaving out those who die of other causes). Of course, patients might live more than 5 years after diagnosis.

Colon cancer survival rates*