WHAT DOES GENETICS HAVE TO DO WITH COLON AND RECTAL CANCER?
Genes are the biochemical information that we inherit from each of our parents. They determine our varied physical features and may predispose us to certain diseases. Probably all cancers, especially colon and rectal cancer (CRC), have hereditary genetic factors that potentially increase an individual's risk to develop these malignancies. In other words, genes are the reason why some diseases such as CRC occur more frequently in certain families. For this reason, when visiting a colon and rectal surgeon, it is important to provide a detailed family history with regard to cancer.
ARE THERE DIFFERENT TYPES OF COLON AND RECTAL CANCER?
From a genetic perspective, there are three broad classifications of CRC. The table below shows the respective proportion of each different classification.
Sporadic Colon Cancer50-60%
Familial Colon Cancer30-40%
Inherited Colon Cancer Syndromes4-6%
WHAT IS SPORADIC COLON CANCER?
Sporadic colon cancer generally occurs in someone over age 60, without a prior family history of CRC. Patients who develop CRC as we first member of the family should be encouraged to inform relatives. People with a family history of colon rectal cancer should be advised to inquire about screening protocols at an earlier age.
WHAT IS FAMILIAL COLON CANCER?
Some families are predisposed to getting colon cancer. There should be concern if a family has more than one relative with CRC, especially if the CRC occurred in an individual before age 50. If a first degree relative (parent, sibling, or child) develops a colorectal cancer, the risk of family members developing this disease is doubled. Individuals with a first degree relative who has been diagnosed with CRC should begin colon cancer screening at 40 years of age or 10 years earlier than the age at which their relative was diagnosed with cancer, whichever is earlier.
WHAT ARE HEREDITARY COLORECTAL CANCERS?
Hereditary colorectal cancers are associated with a specific genetic abnormality. As genetic researchers continue to define certain syndromes, more genes that predispose colorectal cancer will likely be identified. Currently, some of the syndromes include:
- HNPCC (Hereditary Non-Polyposis Colon Cancer, Lynch Syndrome)
- FAP (Family Adenomatous Polyposis)
- aFAP (Attenuated Familial Adenomatous Polyposis)
- APCI 1307K
- Peutz-Jehger's Syndrome
- MAP (MYH associated Polyposis)
- Juvenil e Polyposis
- Hereditary Polyposis
WHAT TYPE OF INFORMATION REGARDING FAMILY HISTORY SHOULD I TELL MY COLON AND RECTAL SURGEON?
Family history information regarding the following items will allow your colon and rectal surgeon to formulate the best plan for prevention and treatment.
- All family members and their approximate ages of when they were diagnosed with colorectal polyps or cancer
- Family history of gynecologic cancers (ovarian or uterine)
WHO IS A COLON & 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. 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.
