| What Is Colorectal Cancer? |
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Colorectal cancer is a term used to refer to cancer that starts in either the colon or the rectum. Colon cancer and rectal cancer have many features in common. They are discussed together here except for the section about treatment, where they are discussed separately.
The normal digestive system
Colon and rectal cancers begin in the digestive system, also called the GI (gastrointestinal) system (see the picture below). This is where food is processed to create energy and rid the body of solid waste matter (stool). In order to understand colorectal cancer, it helps to know some basics about the normal structure and function of the digestive system.
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 width of the small intestine. In fact, the small intestine is the longest part of the digestive system -- about 20 feet.
The small intestine also breaks down the food and absorbs most of the nutrients. The small intestine leads to the large intestine (also called the large bowel or colon), a muscular tube about 5 feet long. 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 last 6 inches of the digestive system. From there the waste passes out of the body through the opening called the anus.
The wall of the colon and rectum has several layers of tissues. Colorectal 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 how deep the cancer goes into these layers.
Abnormal growths in the colon or rectum
Cancer that starts in these different areas may cause different symptoms. But colon cancer and rectal cancer have many things in common. In most cases, colorectal cancers develop slowly over many years. We now know that most of these cancers begin as a polyp--a growth of tissue that starts in the lining and grows into the center of the colon or rectum. This tissue may or may not be cancer. A type of polyp known as an adenoma can become cancerous. Removing a polyp early may prevent it from becoming cancer.
Over 95% of colon and rectal cancers are adenocarcinomas. These are cancers that start in 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.
| What Causes Colorectal Cancer? |
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While we do not know the exact cause of most colorectal cancers, there are certain known risk factors. A risk factor is something that affects 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.
But risk factors don't tell us everything. Having a risk factor, or even several risk factors, does not mean that you will get the disease. And some people who get the disease may not have any known risk factors. Even if a person with colorectal cancer has a risk factor, it is often very hard to know what part that risk factor may have contributed to the cancer.
Researchers have found several risk factors that may increase a person's chance of getting polyps or colorectal cancer.
Risk factors you cannot change
Age: The chances of having colorectal cancer go up after age 50. More than 9 out of 10 people found to have colorectal cancer are older than 50.
Having had polyps or colorectal cancer before: Some types of polyps increase the risk of colorectal cancer, especially if they are large or if there are many of them. If you have had colorectal cancer (even if it has been completely removed), you are more likely to have new cancers start in other areas of your colon and rectum. The chances of this happening are greater if you had your first colorectal cancer when you were younger than age 60.
Having a history of bowel disease: Two bowel 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. If you have either of these diseases your doctor may want you to have colon screening testing more often. (These diseases are different than irritable bowel syndrome (IBS), which does not carry an increased risk for colorectal cancer.)
Family history of colorectal cancer: If you have close relatives who have had this cancer, your risk might be 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 when and 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 called FAP that involves having hundreds of polyps in their colon or rectum. Cancer often develops in 1 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 want to talk about genetic counseling.
Race or ethnic background: Some racial and ethnic groups such as African Americans and Jews of Eastern European descent (Ashkenazi Jews) have a higher colorectal cancer risk. All of the reasons for this are not yet understood.
Risk factors linked to things you do
Several lifestyle-related factors have been linked to colorectal cancer. In fact, the links between diet, weight, and exercise and colorectal cancer risk are some of the strongest for any type of cancer.
Certain types of diets: A diet that is high in red meats (beef, lamb, or liver) and processed meats such as hot dogs, bologna, and lunch meat can increase your colorectal cancer risk. Cooking meats at very high heat (frying, broiling, or grilling) can create chemicals that might increase cancer risk. Diets high in vegetables and fruits have been linked with a lower risk of colorectal cancer.
Lack of exercise: Getting more exercise may help reduce your risk.
Overweight: Being very overweight increases a person's risk of dying from colorectal cancer.
Smoking: Most people know that smoking causes lung cancer, but long-time smokers are more likely than non-smokers to die of colorectal cancer. Smoking increases the risk of many other cancers, too.
Alcohol: Heavy use of alcohol has been linked to colorectal cancer.
Diabetes: People with type 2 diabetes have an increased chance of getting colorectal cancer. They also tend to have a higher death rate from this cancer.
Risk factors that are less certain
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 to check out this finding.
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, too.
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.
| How Is Colorectal Cancer Found? |
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Colorectal cancer screening tests 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. The tests used to screen for polyps and colorectal cancer can be divided into 2 broad groups:
- Tests that can find both colorectal polyps and cancer: These tests are done either with a scope inserted into the rectum or with special x-ray tests. Polyps found before they turn into cancer can be removed, so these tests may prevent colorectal cancer. Because of this, they are preferred if they are available and you are willing to have them.
- Tests that mainly find cancer: These involve testing the stool (feces) for signs of cancer. These tests are easier to have done, but they are less likely to find polyps.
Tests that can find both colorectal polyps and cancer
Flexible sigmoidoscopy (flex-sig): A sigmoidoscope is a thin, flexible, 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 some medicine to clean out your colon. If a small polyp is found your doctor may remove it during this test. If an adenoma polyp or colorectal cancer is found during the flex-sig, you will need to have a colonoscopy to look for polyps or cancer in the rest of the colon.
Colonoscopy: A colonoscope is a longer version of the sigmoidoscope. It is used the same way but 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.
Before the test: The colon and rectum must be empty and clean. You will need to some medicine to clean out your colon the day before the test and maybe an enema that morning. Your doctor will give you exact instructions. Be sure to read these carefully a few days ahead of time, since you may need to shop for special supplies and get laxatives from a drug store. If you are not sure about anything, call the doctor's office and go over them step by step with the nurse. Many people find the bowel preparation to be the most unpleasant part of the test, as you will most likely be in the bathroom quite a bit. You may be given other instructions, too, such as foods to avoid for a certain amount of time before the test.
During the test: The test itself usually takes about 30 minutes, but it may take longer if a polyp is found and removed. Before the test begins, you will be given medicine through your vein to make you feel comfortable and sleepy. You may be awake, but you may not be aware of what is going on and may not remember the test afterward. Most people will be fully awake by the time they get home from the test.
You may need to have someone drive you home from the test because the medicine used can affect your ability to drive. Some doctors require that someone drive you home.
Double contrast barium enema (DCBE): To do this test 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 pictures to be taken. If an area does not look normal you will need to have a colonoscopy.
The preparation for this test is similar to that for the colonoscopy (above), although for the DCBE you will not be given drugs to make you sleepy.
Virtual colonoscopy: You might think of this as a super x-ray or CT scan of the colon. The CT scanner takes many pictures as it rotates around you while you lie on a table. A computer then combines these pictures into images of slices of the part of your body being studied. Virtual colonoscopy ( also calledCT colonography) involves the use of special computer programs to create both 2 dimensional x-ray pictures and a 3-D "fly-through" view of the inside of the colon and rectum, which allows the doctor to look for polyps or cancer.
This test may be useful for some people who can't have or don't want to have tests such as colonoscopy. It can be done fairly quickly and you do not need sedation. But while this test is not invasive like colonoscopy, it still requires the same type of bowel preparation. If polyps or other problems are seen on this test, a colonoscopy will likely be needed to remove them or to explore them fully.
Tests that mainly find colorectal cancer
These tests are used to find small amounts of hidden (occult) blood in the stool. Most people find these tests to be easier because they can often be done at home. But they are not as good at finding polyps as the tests described above, and a positive result on one of these screening tests will likely mean you will need a test such as colonoscopy.
These tests have different names such as FOBT, FIT, and iFIT. They are all alike in that you will need to collect samples of your stool (bowel movement) to be sent to a lab for testing. They differ in the exact way in which you collect the samples and in how the samples are studied in the lab.
If you are having one of these tests, the doctor or nurse will give you a kit with exact instructions on what to do ahead of time (there may be some limits on what you can eat or drink or medicines that you take) and how to collect the samples.
Some people who are given the kits never do the test or don't give it to their doctor because they worry that they might not have followed the instructions right. Be sure to talk to your doctor or nurse if you have any questions about what you should do or how to collect the samples. The most important thing is to get the test done.
Most of these tests need to be done every year, and, as mentioned before, if the lab spots any problems, you will need to have more tests, such as a colonoscopy.
Preventing colorectal cancer or finding it early
Colon cancer begins with a growth (a polyp) that is not yet cancer. Testing can help your doctor tell whether there is a problem, and some tests can find polyps before they become cancer. Most people who have polyps removed never get colon cancer. If colon cancer is found, you have a good chance of beating it with treatment if it is found early. Testing can find it early.
The American Cancer Society believes that preventing colorectal cancer (and not just finding it early) should be a major reason for getting tested. Finding and removing polyps keeps some people from getting colorectal cancer. Tests that have the best chance of finding both polyps and cancer should be your first choice if these tests are available to you and you are willing to have them.
Doctors will take into account a number of factors when they recommend the tests you should have, how often you should have them, and when you should begin testing. These factors include the following:
- Whether you are at average, increased, or high risk for colorectal cancer
- If you are at increased or high risk, the type of test used and how often it is done will further depend on whether you have had polyps, cancer, or certain other diseases, as well as aspects of your family history.
In general, both men and women at average risk of colorectal cancer should begin screening tests at age 50. But you should talk with your doctor about your own health and your family history so that you can choose the best screening plan for you.
Insurance coverage for colorectal cancer screening
Although there are good colorectal cancer screening tests, not enough people have them done. Some of the reasons could include the lack of awareness of screening tests, costs, and lack of health insurance coverage and/or benefits.
Laws regarding insurance coverage for colorectal cancer screening tests vary by state. The same is true of state Medicaid programs. For people with Medicare, coverage begins at age 50 for the most common colorectal cancer screening tests.
For more information on insurance coverage for colorectal cancer screening tests, please see the separate American Cancer Society document, Colorectal Cancer: Early Detection.
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.
Signs and symptoms of colorectal cancer
- 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
- rectal bleeding, dark stools, or blood in the stool (often, though, the stool will look normal)
- cramping or stomach pain
- weakness and tiredness.
Most of these symptoms are more likely to be caused by something other than colorectal cancer. Still, if you have any of these problems, it's important to see your doctor right away so the cause can be found and treated, if needed.
If there is any reason to suspect colon or rectal cancer you will need to have more 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. (See the section below, "Tests to look for colorectal polyps and cancer.")
Medical history and physical exam: Your doctor will ask you questions about your health, your family history, and she will also do a complete physical exam.
Blood tests
Your doctor may order certain blood tests to help find out if you have colorectal cancer. 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. 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. They are most often used for follow-up of people who have already been treated for colorectal cancer.
Tests to look for colorectal polyps or cancer
If symptoms or the results of the physical exam or blood tests suggest that you might have colorectal cancer, your doctor may want to do some more tests.
Biopsy: In a biopsy, the doctor removes a small piece of the tissue that does not look normal. This is done during a colonoscopy. The tissue is sent to the lab where it is looked at under a microscope to see if cancer is present. While other tests may suggest colorectal cancer, a biopsy is the only way to know this for sure.
Imaging tests
These tests, described below, make pictures of the inside of your body. Imaging tests may be done for a number of reasons, such as to help find out whether a suspicious area might be cancer, to learn how far cancer may have spread, and to help learn if treatment is working.
Computed tomography (CT or CAT) scan
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 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.
CT scans can also be used to guide a biopsy needle into a tumor or metastasis. For this to be done, the patient remains on the CT table, while a radiologist moves a biopsy needle through the skin and toward the mass. A tiny fragment of tissue or a thin cylinder of tissue about ½ inch long and less than 1/8 inch wide is then removed and looked at under a microscope.
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 then 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.
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 look at 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 wand that gives off sound waves is placed into the rectum to look for cancer there and to see if it has spread to nearby organs or tissues. In the other test, used during surgery, the wand is placed against the surface of the liver to see if the cancer has spread there.
Magnetic resonance imaging (MRI) scan
Like CT scans, MRIs show a cross-section of the body. But, MRI uses radio waves and strong magnets instead of radiation to take pictures. 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 narrow tube for the test. This can feel confining and upset people with a fear of closed spaces. The machine also makes a thumping noise, but some places will provide headphones with music to block this out.
Chest X-ray
This test may be done to see whether colorectal cancer has spread to the lungs.
Positron emission tomography (PET) scan
In this test, a type of radioactive sugar is injected into a vein. Then you are put into the PET machine where a special camera can detect the radioactivity. The cancer cells absorb high amounts of the sugar and show up on the pictures as dark "hot spots." 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 (called a catheter) 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 done, the catheter is taken out. Surgeons sometimes use this 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?
This information represents the views of the doctors and nurses serving on the American Cancer Society's Cancer Information Database Editorial Board. These views are based on their interpretation of studies published in medical journals, as well as their own professional experience.
The treatment information in this document is not official policy of the Society and is not intended as medical advice to replace the expertise and judgment of your cancer care team. It is intended to help you and your family make informed decisions, together with your doctor.
Your doctor may have reasons for suggesting a treatment plan different from these general treatment options. Don't hesitate to ask him or her questions about your treatment options.
The 4 main types of treatment for colorectal cancer are
- surgery
- radiation therapy
- chemotherapy (often called just "chemo")
- targeted therapies (called monoclonal antibodies)
Depending on the stage of your cancer, 2 or more types of treatment may be used at the same time, or used one after the other.
Take your time and think about all of your treatment choices. You may want to get a second opinion. This can give you 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
The types of surgery used to treat colon and rectal cancers are slightly different and are described separately.
Colon surgery
Surgery is often the main treatment for earlier stage colon cancer. The surgery is called a colectomy or a segmental resection. Usually the cancer and a length of normal colon on either side of the cancer (as well as nearby lymph nodes) are removed. The 2 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 short-term colostomy may be done to allow the colon to heal.
Most often, surgery is done through an incision in the abdomen, but for some earlier stage cancers a different approach might be an option. In laparoscopic-assisted colectomy, instead of 1 long incision in the abdomen, the surgeon makes several small ones. Special long instruments are put into these small openings and used to remove part of the colon and lymph nodes. This method appears to be about as likely to cure the cancer as the standard approach for earlier stage cancers and patients usually recover faster than they do after the usual operations. But the surgery calls for special skill. If you are thinking about this approach, be sure to look for a skilled surgeon who has done a lot of these operations.
Some very early colon cancers (stage 0 and some early stage I tumors) or polyps can be removed using a colonoscope. When this is done, the surgeon does not have to cut into the abdomen. Early stage cancers that are only on the surface of the colon lining can be removed along with a small amount of nearby tissue. For a polypectomy, the cancer is cut out across the base of the polyp's stalk, the area that looks like the stem of a mushroom.
Rectal surgery
Surgery is usually the main treatment for rectal cancer, too, although radiation and chemotherapy will often be given before surgery. There are several types of surgery for rectal cancer.
Some operations (such as 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. These are described here:
Low anterior resection: This approach is used for cancers near the upper part of the rectum, close to where it connects with the colon. The surgeon makes the incision only in the abdomen. Then he removes the cancer and a small amount of normal tissue on either side of the cancer, along with nearby lymph nodes and a large amount of fatty and fibrous tissue around the rectum. The anus is not affected. After the surgery, the colon is reattached to the anus and waste leaves the body in the usual way.
Abdominoperineal (AP) resection: For cancers in the lower part of the rectum, close to its outer connection to the anus, an abdominoperineal (AP) resection is done. For this the surgeon makes 1 incision in the abdomen, and another in the area around the anus. Because the anus is removed, a colostomy is needed. A colostomy is an opening of the colon in the front of the abdomen. It is used for the body to get rid of solid body waste (feces or stool).
Pelvic exenteration: 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 (an opening to collect urine) is also needed.
Side effects of colorectal surgery
Side effects of surgery depend on several things, such as the extent of the operation and a person's general health before surgery. Most people will have at least some pain after the operation, but this can usually be controlled with medicines if needed. Eating problems usually inprove within a few days of surgery.
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 scar tissue in your abdomen (called adhesions) that could cause the bowel to become blocked.
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.
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 comes out. In some cases an AP resection may make you unable to have erections or 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. This is not harmful. But 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 colorectal surgery, you should not normally find any loss of sexual function. Scar tissue may sometimes cause pain or discomfort during intercourse. And if the uterus is removed, pregnancy will not be possible.
For men and women, a colostomy can affect your body image and your sexual comfort level. While you may need to make some adjustments, it should not keep you from having an enjoyable sex life.
The American Cancer Society has more information for both men and women about sexuality and cancer. Please see the list of booklets at the end of this article.
Surgery for colorectal cancer that has spread
Sometimes, surgery for cancer that has spread to other organs can help you to live longer or, depending on the extent of the disease, may even cure you. If the colorectal cancer has spread to a few areas in liver or lungs (and nowhere else), the cancer can sometimes be removed by surgery.
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 (brachytherapy or internal or implant radiation).
After surgery, radiation can kill small areas of cancer that may not be removed 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 can't 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-beam radiation therapy: In this method, radiation is focused on the cancer from a machine outside the body. This approach 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 although the setup time -- getting you into place for treatment -- usually takes longer.
A different approach may be used for some cases of rectal cancer with small tumors. The radiation can be aimed through the anus and reaches the rectum without passing through the skin of the abdomen. This means it is less likely to damage nearby tissues and cause side effects.
Brachytherapy (internal radiation therapy): In this method, small pellets or seeds of radioactive material are placed next to or directly into the cancer. The radiation travels only a short distance, limiting the effects on nearby healthy tissues. 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
Side effects of radiation therapy for colon or rectal cancer include mild skin irritation, nausea, diarrhea, trouble controlling your bowel, rectal or bladder irritation, or tiredness. Sexual problems may also occur. Side effects often go away after treatment is over. If you have these or other side effects, talk to your doctor. There are often ways to reduce or relieve many of these problems.
Chemotherapy
Chemotherapy (often called simply "chemo") is the use of drugs to fight cancer. The drugs may be 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.
Chemo after surgery can increase the survival rate for patients with some stages of colorectal cancer. Chemo can also help relieve symptoms of advanced cancer.
In some cases, chemo 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.
Side effects of chemotherapy
While chemo kills cancer cells, it also damages some normal cells and this can cause 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
- hair loss
- hand and foot rashes and swelling
- mouth sores
- increased chance of infection
- easy bleeding or bruising after minor cuts or injuries
- severe tiredness (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
Targeted therapies are drugs that attack a part of cancer cells that makes them different from normal cells. Because these drugs affect only cancer cells, they often cause fewer side effects than chemo. Man-made proteins called monoclonal antibodies have been approved for use, along with chemo, against colorectal cancer.
Colorectal cancer survival rates
The 5-year survival rate is the percentage of patients who are alive 5 years after their cancer is found (leaving out those who die of other causes). Many of these patients live much longer than 5 years. While the numbers below are among the most current we have, they are from people who were first treated many years ago. Because cancer treatment continues to improve, the survival rates for people now may be higher.
Survival rates for colon cancer by stage
| Stage I | 93% |
| Stage IIA | 72% |
| Stage IIB | 72% |
| Stage IIIA | 83%* |
| Stage IIIB | 64% |
| Stage IIIC | 44% |
| Stage IV | 8% |
*In this study, survival was better for stage IIIA than for stage IIB. The reasons for this are not clear, and it is not known if this is still the case.
Relative survival rates for rectal cancer by stage
| Stage | Relative 5-year Survival Rate |
| Stage I | 92% |
| Stage II | 73% |
| Stage III | 56% |
| Stage IV | 8% |
These numbers provide an overall picture, but keep in mind that every person is unique and statistics can’t predict exactly what will happen in your case. Talk with your cancer care team if you have questions about your own chances of a cure, or how long you might survive your cancer. They know your situation best.
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