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Comprehensive COLARIS AP®
POSITIVE FOR A DELETERIOUS MUTATION IN THE APC GENE
 This test result means that a deleterious mutation was found in the APC gene, indicating a diagnosis of familial adenomatous polyposis (FAP) or attenuated FAP (AFAP). These adenomatous polyposis syndromes are associated with an increased risk for colorectal adenomas and various other associated cancers. If your patient has already been diagnosed with cancer and/or colorectal adenomas, he/she is at increased risk for second primary cancers and colorectal adenomas. Click here to a view a list of published estimates of cancer risks for APC mutation carriers.
Download the Results Patient Education Tool
COLARIS AP® Positive for a Deleterious Mutation or Suspected Deleterious
A
positive for a deleterious mutation in the APC gene result allows you to personalize your patient's medical management, as the diagnosis of FAP or AFAP is genetically confirmed. It also enables other family members to determine whether they also inherited the mutation and its associated cancer susceptibility.
Medical Management Recommendations
COLORECTAL CANCER
Increased Surveillance
Familial Adenomatous Polyposis (FAP)
- Flexible sigmoidoscopy annually, beginning at age 10-12
- Esophagogastroduodenoscopy (EGD) every 1-3 years (depending on adenoma burden) beginning at age 20-25
Attenuated FAP (AFAP)
- Colonoscopy every 1-3 years, beginning during the late teens to early twenties
- Esophagogastroduodenoscopy (EGD) every 1-3 years (depending on adenoma burden) beginning at age 20-25
Prophylactic Surgery
FAP
- Colectomy following the development of adenomas
AFAP
- For patients diagnosed with AFAP, prophylactic colectomy may not be necessary; surgery should be considered on an individual case-by-case basis
Post Colectomy
- Flexible sigmoidoscopy (following prophylactic subtotal colectomy) of the remaining ileal pouch and rectal epithelium every 6 months to 3 years, depending on the number of adenomas found during the previous exam
* Optional post-surgical chemopreventive agents if surgery is rectum sparing
EXTRA-COLONIC CANCER
Surveillance
- Screening for other FAP/AFAP cancers (thyroid, brain, pancreatic, hepatoblastoma, etc.) may be considered
Implications for Family Members
Once an APC mutation has been detected in a family, other family members can be tested for the specific family mutation. First-degree relatives are at 50% risk to carry the same mutation, since mutations in this gene are inherited in an autosomal dominant pattern. Those family members testing positive for the known mutation are managed more aggressively in order to detect cancer/adenomas early. In contrast, relatives who did not inherit the family mutation are not at increased risk for cancer and adenomas associated with FAP or AFAP and may adhere to general population screening guidelines, as long as there is no independent history of cancer on the other side of the family.
First-degree relatives include an individual's parents, siblings, and children. Click here for a pedigree that indicates which family members are first-degree, second-degree, and third-degree. Other more distant family members, such as nieces, nephews, aunts, uncles, and cousins, may also be at risk to have the same gene mutation found in your patient. In order to determine which side of the patient's family carries the mutation, the parents may have Single Site COLARIS AP® to determine their mutation status. For some patients, it may be possible to assume which side of the family is at risk, based on the history of cancer in the family. If possible, the suspected parent's carrier status should be confirmed through genetic testing. It is important to remind patients about the importance of sharing their genetic information with at-risk family members.
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