Women's Health Matters

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Diagnosing Colorectal Cancer

When detected early, colorectal cancer is highly treatable. It is important that women over the age of 50 and women with risk factors, such as a family history of colorectal cancer, a history of polyps or symptoms of colorectal cancer, get screened regularly for colorectal cancer. Screening means being tested when there are no symptoms. The screening tests used to detect colorectal cancer vary, depending on a woman’s risk factors.

Because age is the number one factor associated with colorectal cancer, any woman 50 years or older should discuss screening tests with her doctor. More than 90 percent of cases of colorectal cancer occur in people over the age of 50.

A number of other factors can increase a woman's risk of developing this disease, including a family history of colorectal cancer. If a woman has a family history, she may need to get screened earlier. Women whose screening tests suggest polyps or other abnormalities need further testing.

Who is at high risk of colorectal cancer?

Some illnesses and inherited conditions increase a person's risk of developing colorectal cancer. For people with these conditions, a more thorough screening program is recommended.

Conditions associated with an increased risk of colorectal cancer include:

  • a personal history of colorectal cancer or polyps

  • a personal history of inflammatory bowel disease (ulcerative colitis or Crohn's disease, which cause inflammation in the lining of the colon)

  • a personal history of ovarian or endometrial cancer

  • a family history of colorectal cancer or colonic polyps

Although they account for only five percent of colorectal cancers, a number of inherited genetic conditions increase some people’s risk of developing colorectal cancer. People who have these inherited conditions or any of the high-risk conditions listed above should have a colonoscopy.

Genetic conditions associated with colorectal cancer

In some families, a rare genetic mutation makes it more likely that a family member will develop colorectal cancer. These inherited conditions include:

  • Familial Adenomatous Polyposis (FAP)
    A person with familial adenomatous polyposis (FAP) develops hundreds or even thousands of polyps in the colon and rectum. FAP usually appears during the teenage years. In the vast majority of cases, cancer develops in one or more of these polyps, usually between the ages of 30 and 50, but sometimes at a younger age. This condition occurs because a gene that normally prevents tumour growth is absent or damaged.

  • Hereditary Nonpolyposis Colon Cancer (HNPCC)
    Hereditary nonpolyposis colon cancer (HNPCC, also known as Lynch Syndrome) is the most common type of genetic colorectal cancer. People with this condition tend to develop cancer at a young age, but do not have as many polyps as those with FAP (described above). HNPCC is the result of a genetic defect, which prevents the body from repairing genetic errors in new cells. HNPCC increases a person’s risk of developing other cancers as well.

  • Peutz-Jeghers Syndrome (JPS)
    Peutz-Jeghers Syndrome (JPS) causes polyps on a person’s small intestine and colon, as well as small dark freckles on their cheeks, lips, fingertips and toes. These blue, brown or black freckles often appear during infancy or childhood, providing an early indication that a child has the disease.  

  • Juvenile Polyposis
    People with juvenile polyposis develop polyps throughout their gastrointestinal tract, especially in the large intestine and bowel, in early childhood. These polyps often become cancerous. The disease is frequently misdiagnosed because of its similarity to FAP.

Tests have been developed to detect the genetic mutations that cause syndromes such as FAP and HNPCC. In families where these mutations have been identified, testing can help determine which members of the families have inherited the condition. Genetic testing is usually available only if a member of your family has colorectal cancer and has been found to carry one of these genetic mutations. A genetic counselor can discuss the benefits and risks of genetic testing with you.

People with these conditions should have a colonoscopy at an early age, to be screened for colorectal cancer.

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  • A publication of:
  • Women's College Hospital