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Hereditary Colorectal Cancer

Hereditary Colorectal Cancer | ASCRS

Alternate Titles: 
Genetics and Colorectal Cancer

THE ROLE OF GENETICS

Genes are inherited from each parent. They determine various physical features and may predispose people to certain diseases. All cancers, but especially colon and rectal cancers, commonly referred to as colorectal cancer (CRC), have hereditary factors that potentially increase one’s risk. Genes are the underlying reason why many diseases such as CRC affect some families more often. For this reason, it is important to provide physicians with a detailed family history of cancer.

COLORECTAL CANCER CLASSIFICATIONS 

There are three broad classifications of CRC, two of which have a genetic component. The data below show the respective percentages for each type.

  • Sporadic Colorectal Cancer: 50% to 60%.
  • Familial Colorectal Cancer: 30% to 40%.
  • Hereditary Colorectal Cancers: 4% to 6%.

SPORADIC COLORECTAL CANCER

Sporadic colorectal cancer is the most common type, with 90% of people diagnosed at age 50 or older. It is not directly related to genetics or a family history. About 1 in 20 Americans develop this type of CRC. When a person is the first family member to be diagnosed with CRC, they should inform close relatives. People with a family history are advised to receive screenings at a younger age.

FAMILIAL COLON CANCER

Some families are predisposed to CRC. If a family has more than one relative with CRC, especially if it occurred before age 50, there is reason for concern. The risk for family members doubles when a first degree relative (parent, sibling or child) has it.

People with a close relative with CRC or colorectal polyps should receive their first screening at age 40, or 10 years before the youngest age at which the relative was diagnosed. These screenings should be done every five years, even if the test was normal.

HEREDITARY COLORECTAL CANCERS

Hereditary colorectal cancers are associated with a specific inherited genetic abnormality. As genetic researchers continue to define certain syndromes, more genes that predispose one to CRC will likely be identified. Currently, some of the syndromes include:

  • Hereditary Non-Polyposis Colon Cancer, Lynch Syndrome (HNPCC).
  • Familial Adenomatous Polyposis (FAP).
  • Attenuated Familial Adenomatous Polyposis (AFAP).
  • APCI 1307K.
  • Peutz-Jehger’s Syndrome.
  • MYH Associated Polyposis (MAP).
  • Juvenile Polyposis.
  • Hereditary Polyposis.

IMPORTANCE OF FAMILY MEDICAL HISTORY

Family history information enables your colon and rectal surgeon to assess your risk of CRC and formulate the best plan for prevention and treatment. It is important to share the following:

  • A list of all family members diagnosed with colorectal polyps or cancer, with estimated age(s) at time of diagnosis.
  • Family history of breast, ovarian or uterine cancer.

Additional patient evaluations can help detect and identify family cancer syndromes. These may include genetic counseling, formal genetic testing, colonoscopy, regular follow-up exams and possible referral to other medical specialists.

WHAT IS A COLON AND RECTAL SURGEON?

Colon and rectal surgeons are experts in the surgical and non-surgical treatment of diseases of the colon, rectum and anus. They have completed advanced surgical training in the treatment of these diseases as well as full general surgical training. Board certified colon and rectal surgeons complete residencies in general surgery and colon and rectal surgery, and pass intensive examinations conducted by the American Board of Surgery and the American Board of Colon and Rectal Surgery. They are well-versed in the treatment of both benign and malignant diseases of the colon, rectum and anus and are able to perform routine screening examinations and surgically treat conditions if indicated to do so.

DISCLAIMER

The American Society of Colon and Rectal Surgeons is dedicated to ensuring high-quality patient care by advancing the science, prevention and management of disorders and diseases of the colon, rectum and anus. These brochures are inclusive but not prescriptive. Their purpose is to provide information on diseases and processes, rather than dictate a specific form of treatment. They are intended for the use of all practitioners, health care workers and patients who desire information about the management of the conditions addressed. It should be recognized that these brochures should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtain the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all the circumstances presented by the individual patient. 

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