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What is Colorectal Cancer?

Colorectal cancer is the third most commonly diagnosed cancer in men and women in the U.S. Colorectal cancer used to be the second most commonly diagnosed cancer in the U.S. But as more people have gone for routine colorectal cancer screening, incidence rates for this cancer have decreased. Statistics show that from 2007 to 2011, incidence rates for colorectal cancer declined by 4% per year among adults 50 years of age and older. However, they increased 2% per year among adults younger than age 50.

The decreased incidence in adults over age 50 can be attributed, in part, to cancer screening. That’s because some colorectal cancer screening tests, like colonoscopy, allow doctors to remove colorectal polyps before they become cancerous. The American Cancer Society recommends screening start at age 45 for people with average risk, while US Preventative Services Task Force still recommends screening starting at age 50. The reason why rates are increased among younger adults isn’t fully understood.

Deaths from colorectal cancer have actually been declining for women and men for decades, and may be attributed to improved treatment as well increased awareness about colorectal cancer screening.

Risk Factors

The risk of colorectal cancer increases with age. About 90% of colorectal cancer cases are diagnosed in women and men age 50 and older.

Some of the risk factors for colorectal are lifestyle factors that it may be possible for you to change. These include:

  • Obesity
  • Little or no physical activity
  • Moderate to heavy alcohol use
  • Smoking
  • Eating a lot of red or processed meat
  • Not getting enough calcium
  • Not eating enough whole grains, fruit and vegetables.

Other risk factors you have no control over. These include:

  • A personal history of polyps in the colon family history of colorectal cancer and/or polyps
  • A personal history of cancer of the ovary, endometrium (lining of the uterus) or breast. 
  • Chronic inflammatory bowel disease (ulcerative colitis or Crohn dis­ease)
  • Type 2 diabetes
  • Inherited genetic conditions, such as Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC), and familial adenomatous polyposis (FAP).

Knowing you have an inherited genetic condition or a family history of certain cancers that suggests you may be at increased risk for colorectal cancer is important because it affects the age you should begin screening, the type of screening you receive, and how often you are screened.

Signs and Symptoms

Many people with colorectal cancer have no symptoms at all. That’s because symptoms often only begin to occur when the cancer is more advanced.
Possible signs of colorectal cancer include: 

  • Blood (either bright red or very dark) in the stool 
  • Change in bowel habits 
  • Constant tiredness or anemia 
  • Diarrhea, constipation, or feeling that the bowel does not empty completely 
  • General abdominal discomfort (frequent gas pains, bloating, fullness, or cramps) 
  • Stools that are narrower than usual 
  • Vomiting 
  • Weight loss with no known reason 

If you have these symptoms, it is important to see your doctor for a physical examination, blood tests and a colonoscopy.

Diagnosis & Staging


There are a number of things that can lead to a colorectal cancer diagnosis. It’s possible that you called your doctor for an appointment because you were not feeling well and you have certain signs or symptoms that suggest you may have colorectal cancer. You may have gotten a positive result on a fecal occult blood test, which led your doctor to recommend a colonoscopy. Or, you may have had a colonoscopy where your doctor saw an area of concern and removed some tissue to have it biopsied.

These steps will likely include a:

  • Physical Exam
  • Colonoscopy
  • Blood Tests
  • Imaging Studies
  • Tumor Tissue Tests

Diagnosing Colorectal Cancer


Cancers are “staged” because a cancer’s stage helps determine the best treatments. The stage is determined by the cancer’s size and whether it has spread to nearby lymph nodes or other parts of the body. If your cancer spreads to the bone, visit our bone metastases page.

Staging of Colorectal Cancer depends on three factors:

  • T — for Tumor: How far the tumor extends from the inner lining of the colon through the layers of its walls. 
  • N — for Nodes: Whether cancer cells are found in the lymph nodes near the site of the cancer and how many nodes are affected. Lymph nodes are small, bean-shaped structures found throughout the body that filter substances in a fluid called lymph and help fight infection and disease. 
  • M — for Metastasis: Whether cancer has spread beyond the colon and its adjacent tissues to distant organs like the lungs or liver.

Stages of Colorectal Cancer

Treatment & Side Effects Management


Your treatment options will depend on your cancer’s stage, your age and your overall health. It is important for you and your doctor to decide together what treatment is best for you. It is also perfectly ok for you to get a second opinion from another doctor about your treatment options. Knowing that another doctor agrees with the first doctor or finding out you have other options can help you feel confident about the choices you have made.

You do not have to rush to make a decision. Ask questions if you do not understand any aspect of treatment or the terms your doctors are using. Bring someone along for support, or to take notes. Also, consider recording your conversations with your doctor. It’s a lot of information to take in at one time and having the recording will allow you to re-listen to the conversation as you consider your options. You may also want to talk to an oncology nurse. The nurse can help you understand your options and may have more time to talk though questions than your doctor does.

Treatment for colorectal cancer can include:

  • Surgery
  • Ostomy
  • Chemotherapy
  • Chemoradiation
  • Targeted Therapy

Learn More About Colorectal Cancer Treatments