Colon Cancer Facts
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Introduction
Cancer of the colon or rectum is also called colorectal cancer. In the United States, colorectal cancer is the fourth most common cancer in men, after skin, prostate, and lung cancer. It is also the fourth most common cancer in women, after skin, lung, and breast cancer. This National Cancer Institute (NCI) booklet (NIH Publication No. 03-1552) has important information about the possible causes, symptoms, diagnosis, and treatment of colorectal cancer. It also has information to help patients cope with the disease. Scientists are studying colorectal cancer to learn more about it. They are finding out more about its causes and are exploring new ways to prevent, detect, and treat it. This research is increasing our knowledge about colorectal cancer. The NCI provides the most up-to-date information by telephone and on the Internet:
The colon and rectum are parts of the digestive system. They form a long, muscular tube called the large intestine (also called the large bowel). The colon is the first 4 to 5 feet of the large intestine, and the rectum is the last 4 to 5 inches. The part of the colon that joins to the rectum is the sigmoid colon. The part that joins to the small intestine is the cecum. Partly digested food enters the colon from the small intestine. The colon removes water and nutrients from the food and stores the rest as waste. The waste passes from the colon into the rectum and then out of the body through the anus.  This picture shows the colon and rectum.
Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body. Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place. Sometimes this orderly process goes wrong. New cells form when the body does not need them, and cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor. Tumors can be benign or malignant:
Colorectal Cancer Cancer that begins in the colon is called colon cancer, and cancer that begins in the rectum is called rectal cancer. Cancers affecting either of these organs may also be called colorectal cancer. When colorectal cancer spreads outside the colon or rectum, cancer cells are often found in nearby lymph nodes. If cancer cells have reached these nodes, they may also have spread to other lymph nodes, the liver, or other organs. When cancer spreads (metastasizes) from its original place to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if colorectal cancer spreads to the liver, the cancer cells in the liver are actually colorectal cancer cells. The disease is metastatic colorectal cancer, not liver cancer. It is treated as colorectal cancer, not liver cancer. Doctors sometimes call the new tumor "distant" or metastatic disease.
No one knows the exact causes of colorectal cancer. Doctors can seldom explain why one person develops the disease and another does not. However, it is clear that colorectal cancer is not contagious. No one can "catch" this disease from another person. Research has shown that people with certain risk factors are more likely than others to develop colorectal cancer. A risk factor is anything that is linked to an increased chance of developing a disease. Studies have found the following risk factors for colorectal cancer:
People who think they may be at risk should discuss this concern with their doctor. The doctor may be able to suggest ways to reduce the risk and can plan an appropriate schedule for checkups.
Screening for cancer before a person has symptoms can help the doctor find polyps or cancer early. Finding and removing polyps may prevent colorectal cancer. Also, treatment for colorectal cancer is more likely to be effective when the disease is found early.  To find polyps or early colorectal cancer:
The following screening tests are used to detect polyps, cancer, or other abnormalities in the colon and rectum. The doctor can explain more about each test:
   
Common symptoms of colorectal cancer include:
Most often, these symptoms are not due to cancer. Other health problems can cause the same symptoms. Anyone with these symptoms should see a doctor so that any problem can be diagnosed and treated as early as possible. Usually, early cancer does not cause pain. It is important not to wait to feel pain before seeing a doctor.
If a person has any signs or symptoms of colorectal cancer, the doctor must determine whether they are due to cancer or some other cause. The doctor asks about personal and family medical history and may do a physical exam. If the physical exam and test results do not suggest cancer, the doctor may decide that no further tests are needed and no treatment is necessary. However, the doctor may recommend a schedule for checkups. If tests show an abnormal area (such as a polyp), a biopsy to check for cancer cells may be necessary. Often, the abnormal tissue can be removed during colonoscopy or sigmoidoscopy. A pathologist checks the tissue for cancer cells using a microscope.
If the biopsy shows that cancer is present, the doctor needs to know the extent (stage) of the disease to plan the best treatment. The stage is based on whether the tumor has invaded nearby tissues, whether the cancer has spread and, if so, to what parts of the body. Staging may involve some of the following tests and procedures:
The doctor also may use other tests (such as MRI) to see whether the cancer has spread. Sometimes staging is not complete until the patient has surgery to remove the tumor. Doctors describe colorectal cancer by the following stages:
Many people with colorectal cancer want to take an active part in making decisions about their medical care. They want to learn all they can about their disease and their treatment choices. However, shock and stress after the diagnosis can make it hard to think of everything they want to ask the doctor. It often helps to make a list of questions before an appointment. To help remember what the doctor says, people may take notes or ask whether they may use a tape recorder. When they talk to the doctor, some people also want to have a family member or friend with them to take part in the discussion, to take notes, or just to listen. The doctor may refer a person with colorectal cancer to a specialist, or the patient may ask for a referral. Specialists who treat colorectal cancer include gastroenterologists (doctors who specialize in diseases of the digestive system), surgeons, medical oncologists, and radiation oncologists. Getting a Second Opinion Before starting treatment, people with colorectal cancer might want a second opinion about their diagnosis and treatment options. Some insurance companies require a second opinion; others may cover a second opinion if the patient or doctor requests it. It may take some time and effort to gather medical records and arrange to see another doctor. In general, taking several weeks to get a second opinion does not make treatment less effective. In some cases, however, people with colorectal cancer need immediate care. There are a number of ways to find a doctor for a second opinion:
Preparing for Treatment The doctor develops a treatment plan to fit each person's needs. Treatment for colorectal cancer depends mainly on the location of the tumor in the colon or rectum and the stage of the disease. The doctor can describe the treatment choices and the expected results.
People do not need to ask all of their questions at once. They will have other chances to ask the doctor to explain things that are not clear and to ask for more information. Methods of Treatment Treatment for colorectal cancer may involve surgery, rapy'); radiation therapy, or chemotherapy. Some people have a combination of treatments. Colon cancer sometimes is treated differently from rectal cancer. Treatments for colon and rectal cancer are described separately. At any stage of colorectal cancer, treatments are available to control pain and other symptoms, to relieve the side effects of therapy, and to ease emotional and practical problems. This kind of treatment is called supportive care, symptom management, or palliative care. Information about supportive care and coping with cancer is available on NCI's Web site at http://cancer.govhttp://cancer.gov/cancerinfo/coping/ and from NCI's Cancer Information Service at 1-800-4-CANCER. People with colorectal cancer may want to talk to the doctor about taking part in a clinical trial, a research study of new treatment methods. Surgery Surgery is the most common treatment for colorectal cancer. It is a type of local therapy. It treats the cancer in the colon or rectum and the area close to the tumor. A small malignant polyp may be removed from the colon or upper rectum with a colonoscope. Some small tumors in the lower rectum can be removed through the anus without a colonoscope. For a larger cancer, the surgeon makes an incision into the abdomen to remove the tumor and part of the healthy colon or rectum. Some nearby lymph nodes also may be removed. The surgeon checks the rest of the intestine and the liver to see if the cancer has spread. When a section of the colon or rectum is removed, the surgeon can usually reconnect the healthy parts. However, sometimes reconnection is not possible. In this case, the surgeon creates a new path for waste to leave the body. The surgeon makes an opening (a stoma) in the wall of the abdomen, connects the upper end of the intestine to the stoma, and closes the other end. The operation to create the stoma is called a colostomy. A flat bag fits over the stoma to collect waste, and a special adhesive holds it in place. For most people who have a colostomy, it is temporary. It is needed only until the colon or rectum heals from surgery. After healing takes place, the surgeon reconnects the parts of the intestine and closes the stoma. Some people, especially those with a tumor in the lower rectum, need a permanent colostomy.
Chemotherapy Chemotherapy uses anticancer drugs to kill cancer cells. It is called systemic therapy because it enters the bloodstream and can affect cancer cells throughout the body. The patient may have chemotherapy alone or combined with surgery, radiation therapy, or both. Chemotherapy given before surgery is called neoadjuvant therapy. Chemotherapy before surgery may shrink a large tumor. Chemotherapy after surgery is called adjuvant therapy. Adjuvant therapy is used to destroy any remaining cancer cells and prevent the cancer from coming back in the colon or rectum, or elsewhere. Chemotherapy is also used to treat people with advanced disease. Anticancer drugs are usually given through a vein, but some also may be given by mouth. The patient may be treated in an outpatient part of the hospital, at the doctor's office, or at home. Rarely, a hospital stay may be needed.
Radiation Therapy Radiation therapy (also called dow('definition' radiotherapy) is local therapy. It uses high-energy rays to kill cancer cells. It affects cancer cells only in the treated area. Doctors use two types of radiation therapy to treat cancer. Sometimes people receive both types:
Treatment for Colon Cancer Most patients with colon cancer are treated with surgery. Some have both surgery and chemotherapy. A colostomy is seldom needed for people with colon cancer. Although radiation therapy is not commonly used to treat colon cancer, sometimes it is used to relieve pain and other symptoms. Treatment for Rectal Cancer For all stages of rectal cancer, surgery is the most common treatment. Some patients receive surgery, radiation therapy, and chemotherapy. About 1 out of 8 people with rectal cancer needs a permanent colostomy. Radiation therapy may be used before and after surgery. Some people have radiation therapy before surgery to shrink the tumor, and some have it after surgery to kill cancer cells that may remain in the area. At some hospitals, patients may have radiation therapy during surgery. This is called IORT. People also may have radiation therapy to relieve pain and other problems caused by the cancer.
Because treatment often damages healthy cells and tissues, unwanted side effects are common. Side effects depend mainly on the type and extent of the treatment. Side effects may not be the same for each person, and they may change from one treatment session to the next. Before treatment starts, the health care team will explain possible side effects and suggest ways to help the patient manage them. The NCI provides helpful information about cancer treatments and coping with side effects. See Eating Hints for Cancer Patients Surgery It takes time to heal after surgery, and the time needed to recover is different for each person. Patients are often uncomfortable during the first few days. However, medicine can usually control their pain. Before surgery, patients should discuss the plan for pain relief with the doctor or nurse. After surgery, the doctor can adjust the plan if more pain relief is needed. It is common to feel tired or weak for a while. Also, surgery sometimes causes constipation or diarrhea. The health care team monitors the patient for signs of bleeding, infection, or other problems requiring immediate treatment. People who have a colostomy may have irritation of the skin around the stoma. The doctor, nurse, or enterostomal therapist can teach patients how to clean the area and prevent irritation and infection. The section called Chemotherapy The side effects of chemotherapy depend mainly on the specific drugs and the dose. In general, anticancer drugs affect cells that divide rapidly, especially:
Radiation Therapy The side effects of radiation therapy depend mainly on the amount of radiation given and the part of the body that is treated. Radiation therapy to the abdomen and pelvis may cause nausea, vomiting, diarrhea, bloody stools, rectal leakage, or urinary discomfort. In addition, the skin in the treated area may become red, dry, and tender. Patients are likely to become very tired during radiation therapy, especially in the later weeks of treatment. Resting is important, but doctors usually advise patients to try to stay as active as they can. Although the side effects of radiation therapy can be distressing, the doctor can usually treat or control them.
It is important to eat well during cancer treatment. Eating well means getting enough calories to maintain a good weight and enough protein to keep up strength. Good nutrition often helps people with cancer feel better and have more energy. But eating well can be difficult. Patients may not feel like eating if they are uncomfortable or tired. Also, the side effects of treatment, such as poor appetite, nausea, vomiting, or mouth sores, can be a problem. Some people find that foods do not taste as good during cancer therapy. The doctor, dietitian, or other health care provider can suggest ways to maintain a healthy diet. Patients and their families may want to read the National Cancer Institute booklet Eating Hints for Cancer Patients, which contains many useful ideas and recipes.
Rehabilitation is an important part of cancer care. The health care team makes every effort to help the patient return to normal activities as soon as possible. A person with a stoma needs to learn to care for it. Doctors, nurses, and enterostomal therapists can help. Often, enterostomal therapists visit the person before surgery to discuss what to expect. They teach the person how to care for the stoma after surgery. They talk about lifestyle issues, including emotional, physical, and sexual concerns. Often they can provide information about resources and support groups.
Follow-up care after treatment for colorectal cancer is important. Even when the cancer seems to have been completely removed or destroyed, the disease sometimes returns because undetected cancer cells remained somewhere in the body after treatment. The doctor monitors the person's recovery and checks for recurrence of the cancer. Checkups help ensure that any changes in health are noted. Checkups may include a physical exam (including a digital rectal exam), lab tests (including fecal occult blood test and CEA test), colonoscopy, x-rays, CT scans, or other tests. Between scheduled visits with the doctor, patients should contact the doctor as soon as any health problems appear. The NCI has prepared a booklet for people who have completed their treatment to help answer questions about follow-up care and other concerns. Facing Forward Series: Life After Cancer Treatment provides tips for making the best use of medical visits. It describes how to talk to the doctor about creating a plan of action for recovery and future health.
Living with a serious disease such as colorectal cancer is not easy. People may worry about caring for their families, keeping their jobs, or continuing daily activities. Concerns about treatments and managing side effects, hospital stays, and medical bills are also common. Doctors, nurses, and other members of the health care team can answer questions about treatment, working, or other activities. Meeting with a social worker, counselor, or member of the clergy can be helpful to those who want to talk about their feelings or discuss their concerns. Often, a social worker can suggest resources for financial aid, transportation, home care, or emotional support. Support groups also can help. In these groups, patients or their family members meet with other patients or their families to share what they have learned about coping with the disease and the effects of treatment. Groups may offer support in person, over the telephone, or on the Internet. Patients may want to talk with a member of their health care team about finding a support group. The Cancer Information Service can provide information to help patients and their families locate programs, services, and publications.
Doctors all over the country are conducting many types of clinical trials (research studies in which people volunteer to take part). Doctors are studying new ways to prevent, detect, diagnose, and treat colorectal cancer. Clinical trials are designed to answer important questions and to find out whether the new approach is safe and effective. Research already has led to advances in these areas, and researchers continue to search for more effective approaches. People who join clinical trials may be among the first to benefit if a new approach is shown to be effective. And if participants do not benefit directly, they still make an important contribution to medicine by helping doctors learn more about the disease and how to control it. Although clinical trials may pose some risks, researchers do all they can to protect their patients. People who are interested in being part of a clinical trial should talk with their doctor. They may want to read the NCI booklets Taking Part in Clinical Trials: What Cancer Patients Need To Know or Taking Part in Clinical Trials: Deciding to Take Part in a Clinical Trial. Research on Prevention Recent studies suggest that certain drugs may help prevent colorectal cancer. Researchers are studying aspirin, celecoxib, and other drugs in people with a higher-than-average chance of developing this disease. Research on Screening and Diagnosis Researchers are testing new ways to check for polyps and colorectal cancer. One study is looking at the usefulness of virtual colonoscopy. This is a CT scan of the colon. Another study is using genetic testing to check stool samples for colorectal cancer cells. Research on Treatment Researchers are studying chemotherapy, biological therapy, and combinations of treatments:
The National Digestive Diseases Information Clearinghouse is a service of the Federal Government's National Institute of Diabetes and Digestive and Kidney Diseases. This Clearinghouse can supply free information about colon polyps and other noncancerous digestive tract problems. The Web site address for the Clearinghouse is http://digestive.niddk.nih.gov. Materials also may be obtained by writing or calling the Clearinghouse:
National Cancer Institute (NCI) publications can be ordered by writing to the address below:
Some NCI publications can be viewed, downloaded, and ordered from http://cancer.gov/publications on the Internet. In addition, people in the United States and its territories may order these and other NCI booklets by calling the Cancer Information Service at 1-800-4-CANCER.
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