Colorectal cancer (patient information)

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Colorectal cancer


What are the symptoms?

Who is at highest risk?

Diseases with similar symptoms


When to seek urgent medical care?

Treatment options

Where to find medical care for Colorectal cancer?


What to expect (Outlook/Prognosis)?

Colorectal cancer On the Web

Ongoing Trials at Clinical

Images of Colorectal cancer

Videos on Colorectal cancer

FDA on Colorectal cancer

CDC on Colorectal cancer

Colorectal cancer in the news

Blogs on Colorectal cancer

Directions to Hospitals Treating Colorectal cancer

Risk calculators and risk factors for Colorectal cancer

Editor-in-Chief: C. Michael Gibson, M.S.,M.D. [1]; Associate Editor-In-Chief: Jinhui Wu, M.D., Maria Fernanda Villarreal, M.D. [2]


Colorectal cancer is a very common cancer in United States. It includes cancer of the colon or rectum. Symptoms can include general abdominal discomfort, abdominal pain, blood in the stool, narrower stools and a change in bowel habits. However, you may not have symptoms at first, so screening is important. If you are caught early, you may often curable. Treatments for colorectal cancer include surgery, chemotherapy, radiation therapy or a combination.

What are the symptoms of colorectal cancer?

Early colorectal cancer does not make any symptoms. When the cancer grows larger, people with colorectal cancer may experience the following symptoms.

  • Changes in bowel habits such as diarrhea, constipation, or narrowing of the stool that lasts for more than a few days

Other health problems may also cause these symptoms. Only a doctor can tell for sure. A person with any of these symptoms should tell the doctor so that problems can be diagnosed and treated as early as possible.

Who is at highest risk?

There are some factors may increase the risk of acquiring the colorectal cancer potentially. These risk factors are outlined in the table below:

  • Colorectal polyps: Person with a history of adenomatous polyps (adenomas) is at increased risk of developing colorectal cancer, especially with large or many of them.
  • Family history of colorectal cancer: The reasons are not clear in all cases. Inherited genes, shared environmental factors and some combination of these may contribute to the development of colorectal cancer.
  • Familial adenomatous polyposis (FAP): FAP is caused by changes (mutations) in the APC gene that a person inherits from his or her parents. About 1% of all colorectal cancers are due to FAP.
  • Turcot syndrome: This is a rare inherited condition in which people are at increased risk of adenomatous polyps and colorectal cancer.
  • Peutz-Jeghers syndrome: People with this syndrome are at greatly increased risk for multiple kind of cancer besides colorectal cancer.
  • Type 2 diabetes: Clinical data show that people with type 2 diabetes have an increased risk of developing colorectal cancer.
  • Lifestyle-related factors such as diets high in red meats and poor in vegetables and fruits, physical inactivity, smoking and alcohol abuse, obesity and so on.
  • Racial and ethnic background: Among all racial groups in the United States, African Americans have the highest incidence and mortality rates to develope colorectal cancer. The reason is not yet clear.
  • Age: Both youth and aged can develop colorectal cancer. But the chances increase markedly after age 50.

When to seek urgent medical care?

Call your health care provider if symptoms of colorectal cancer develop. If one emerges the following symptoms, seeking urgent medical care as soon as possible:

  • Defecation with a lot of blood: This is the result of cancer invading the vessels of rectum or colon walls. An abundant of blood loss may lead to shock and death. You need to go to hospital as soon as possible.


It is hard to diagnose colorectal cancer in its early stages. Other problems can also cause the same symptoms such as abdominal pain and hemafecia. So, if you have those symptoms, you had better go to see your doctor to do some tests. They include lab tests, image tests and endoscopy. Among them, the latter is the main test.

  • Colonoscopy and biopsy: It is the main test used to diagnose colorectal cancer when people have certain risk factors or when signs and symptoms suggest this disease may be present. After you are sedated, a thin, flexible, lighted tube called endoscope is passed down your anus. Then the doctor can view the lining of your rectum and each section of your colon, up to ileocecal junction. If abnormal areas are noted, biopsies (tissue samples) can be obtained through the endoscope. The tissue samples will be checked by the pathologists under a microscope to see whether cancer is present or not. This is the most important test for colorectal cancer.
  • Computed tomography (CT) scan and guided needle biopsy: CT scans are often used to diagnose colorectal cancer. It can confirm the location of the cancer and show the organs near the large intestine, as well as lymph nodes and distant organs where the cancer might have spread. These are helpful in staging the cancer and in determining whether surgery is a good treatment option. And CT scans can also be used to guide biopsy and a biopsy sample is then removed and looked at under a microscope.
  • Magnetic resonance imaging (MRI): An MRI uses magnetic fields but which is a different imaging type from computed tomography (CT) to produce detailed images of the body. Like computed tomography (CT), a contrast agent may be injected into a patient’s vein to create a better picture. MRI scan may take longer time than CT scan.
  • Positron emission tomography (PET) scan: When doing this test, a small amount of a radioactive medium is injected into your body and absorbed by the organs or tissues. This radioactive substance gives off energy to accept to produce the images. PET can provide more helpful information than CT scan and MRI scan. It is useful to see if the cancer has spread to lymph nodes and also useful for your doctor to locate where the cancer has spread.
  • Tumor markers such as CEA, CA199: These tumor markers are used not as screening tests to find colorectal cancer but as follow-up marker for patients who already have been diagnosed with or treated for colorectal cancer. They may help doctors judge how well treatment is working or provide an early warning of a cancer that has recurred.
  • Blood tests including complete blood tset and liver function test: These are regular tests in hospitals. These tests may help your doctor see whether you have anemia and colorectal cancer has spread to the liver and cause abnormalities or not.

Treatment options

There are four main types of treatment for colorectal cancer: surgery, radiation therapy, chemotherapy and targeted therapies. The option depends on the stage of your cancer. Sometimes two or more types of treatment may be used at the same time or used one after the other. Before treatment starts, ask your health care team about possible side effects and how treatment may change your normal activities. Because cancer treatments often damage healthy cells and tissues, side effects are common. Side effect may not be the same for each person, and they may change from one treatment session to the next.

  • Surgery: Surgery is the main treatment for both colon cancer and rectal cancer. The types of surgery are different for each cancer. For colon cancer, surgery type includes colectomy, segmental resection and laparoscopic-assisted colectomy. As rectal cancer is concerned, there are low anterior resection, proctectomy with colo-anal anastomosis, abdominoperineal (AP) resection and pelvic exenteration.
  • Radiation therapy: It includes external-beam radiation therapy and brachytherapy (internal radiation therapy). This is a cancer treatment to kill cancer cells or keep them from growing by using high-energy x-rays or other types of radiation.
  • Chemotherapy: This treatment is to use drugs to stop the growth of cancer cells either by killing the cells or by stopping them from dividing.
  • Targeted therapy: This type of therapy is to use drugs such as monoclonal antibodies to attack parts of cancer cells.

Diseases with similar symptoms

Symptoms of colorectal cancer have no specificity. Other health problems may also cause similar symptoms. Go to see your doctor to verify your diseases as early as possible. Diseases with similar symptoms are listed in the following:

  • Intestinal tuberculosis

Where to find medical care for colorectal cancer?

Directions to Hospitals Treating colorectal cancer


As a common cancer in the United States, prevention of colorectal is very important. Epidemiology data show the following intervention may help to reduce your risk of colorectal cancer:

  • Regular screening tests: For those with history of colorectal cancer or with precancerous diseases, regular colorectal cancer screening or testing is one of the best ways to help prevent colorectal cancer.
  • Changing lifestyle: Eating little red meats and high in vegetables and fruits, doing physical exercises, quitting smoking and alcohol abuse, controlling weight and avoiding obesity and so on.

What to expect (Outook/Prognosis)?

The prognosis of colorectal cancer varies widely. For patients whose tumor is caught early may often be curable. It depends on the following:

  • The size of the tumor
  • Location of the tumor in the colrectal
  • Whether the cancer has distant spread
  • Patients's general health
  • Whether cancer remains after initial treatment or has recurred


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