Skip to Content

Prevent Colorectal Cancer with Screenings

March is National Colorectal Cancer Awareness Month

March 18, 2011 | Heather Burchfield

What is Colon/Rectal Cancer?

Colorectal cancer begins in the colon or rectum and can be referred as colon or rectal cancer depending upon where the cancer starts. Colon and rectal cancer have many commonalities, but they tend to be treated differently.

In order to understand colorectal cancer, it helps to be familiar with the structure of the digestive system and how it works. The small intestine breaks down your food and absorbs most of the nutrients once it has been chewed, swallowed, and traveled through the esophagus.  The small intestine connects to the large intestine or large bowel, which is made up of the colon, a muscular tube about 5 feet long. The colon stores waste as well as absorbs salt and water. The waste then passes into the rectum and out of the body through the anus.

Most colorectal cancers develop slowly over several years. A tissue growth or tumor typically begins as a non-cancerous polyp on the inner lining of the colon or rectum before the actual cancer develops. A tumor can be benign (non-cancerous), such as a polyp, or malignant (cancerous). Some polyps can morph into cancer but not all. Adenomatous polyps have the potential to change into cancer. Therefore, adenomas are called a pre-cancerous condition. Hyperplastic polyps and inflammatory polyps are usually not pre-cancerous. Although various doctors think that some hyperplastic polyps can become pre-cancerous or create a risk factor of developing adenomas and cancer, particularly when the tumors grow in the ascending colon.

Another pre-cancerous condition that lines the wall of the colon and rectum is dysplasia. Dysplasia is a group of abnormal cells and can change into cancer over time. Many times dysplasia is seen in those who have had ulcerative colitis or Crohn’s disease for several years and both of these illnesses can cause chronic colon inflammation.

If cancer forms within a polyp, it can grow into the wall of the colon or rectum. Cancer cells in the colon/rectum wall can grow into blood or lymph vessels. Once these cancer cells spread, they can travel to nearby lymph nodes or to distant parts of the body, which is called metastasis.

Possible symptoms of colorectal cancer according to the National Cancer Institute include:

  • Change in bowel habits
  • Constipation or diarrhea
  • Feeling that your bowel doesn’t completely empty
  • Finding blood (either bright red or very dark) in your stool
  • Finding your stools are narrower than usual
  • Frequently having gas pains or cramps, or feeling full or bloated
  • Losing weight with no known reason
  • Feeling very tired all the time
  • Nausea or vomiting

Many times these symptoms are not cancer related as other health problems can cause the same symptoms. Anyone with these symptoms should consult with a doctor to be diagnosed and treated as early as possible. Early stages of cancer, typically, do not cause pain, but it is important to visit a doctor before feeling pain.


Regular colorectal screenings is one of the most powerful weapons for preventing colorectal cancer. Other prevention tips include:

  • Genetic testing, screening, and treatment for those with a strong family history
  • Healthy diet, exercise and body weight
  • Taking a daily multi-vitamin containing folic acid or folate
  • Vitamin D and calcium
  • Magnesium
  • Non-steroidal anti-inflammatory drugs (Ex. Ibuprofen and naproxen)
  • Hormone replacement therapy consisting of estrogen and progesterone for postmenopausal women

Early Detection

Many polyps and growths can be detected and removed before they have the chance to turn into cancer with regular screenings. Once a biopsy has been conducted, your doctor will have to know the disease stage in order to prepare a treatment plan. The cancer stage is dependent upon whether the tumor has invaded nearby tissues, spread, and if so, to what parts of the body. Your doctor will more than likely perform some of the following tests:

  • Blood tests: You doctor checks for carcinoembryonic antigen (CEA) and other substances in your blood.
  • Colonoscopy: Your doctor checks for abnormal areas along the entire length of the colon and rectum with a colonoscope.
  • Endorectal ultrasound: This ultrasound can show how deep a rectal tumor has grown or whether the cancer has spread to lymph nodes or other nearby tissues.
  • Chest x-ray: X-rays of your chest may show whether cancer has spread to the lungs
  • CT scan: A CT scan may show whether cancer has spread to the liver, lungs, or other organs.
  • MRI: A MRI may show if the cancer has spread.

See the American Cancer Society Guidelines on Screening and Surveillance for the Early Detection of Colorectal Adenomas and Cancer in People at Increased Risk or at High Risk.

Colon Cancer Risk Factors

Some risk factors cannot be changed, such as:

  • Age (Younger adults can develop colorectal cancer, but 9 out of 10 people diagnosed are older than 50.)
  • Personal history of colorectal polyps or colorectal cancer
  • Personal history of inflammatory bowel disease
  • Family history of colorectal cancer
  • Inherited syndromes (Inherited gene changes that can cause the disease are familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC).)
  • Racial and ethnic background (African-Americans have the highest colorectal cancer incidence and mortality rates of all racial groups in the United States. Jews of Eastern European descent (Ashkenazi) have one of the highest colorectal cancer risks of any ethnic group in the world.)

Lifestyle-related factors

  • Diets high in red and processed meats
  • Cooking meats at very high temperatures (frying, boiling, or grilling)
  • Physical inactivity
  • Obesity
  • Smoking
  • Heavy alcohol use
  • Type 2 diabetes

Facing Diagnosis

Doctors describe colorectal cancer in the following stages:

  • Stage 0: The cancer is found only in the innermost lining of the colon or rectum. Carcinoma in situ is another name for Stage 0 colorectal cancer.
  • Stage I: The tumor has grown into the inner wall of the colon or rectum. The tumor has not grown through the wall.
  • Stage II: The tumor extends more deeply into or through the wall of the colon or rectum. It may have invaded nearby tissues, but cancer cells have not spread to the lymph nodes.
  • Stage III: The cancer has spread to nearby lymph nodes, but not to other parts of the body.
  • Stage IV: The cancer has spread to other parts of the body, such as the liver and lungs.
  • Recurrence: This is cancer that has been treated and has returned after a period of time when the cancer could not be detected. The disease may return in the colon or rectum, or in another part of the body.

Treatment methods are dependent upon the location of the tumor in the colon or rectum along with the cancer stage. Treatment for colorectal cancer may involve surgery, chemotherapy, biological therapy, or radiation therapy. Some people have a combination of treatments.

Sources: National Cancer Institute and American Cancer Society