Colon cancer genetic testing
Your family history indicates a suspiscion for hereditary colorectal cancer? Genetic testing could be recommended by our specialists.
Colorectal cancer (CRC) affects 1 in 20 people during their lifetime. An estimated 25% of all CRC cases present a familial clustering of the disease suggesting a contribution of genetic factors among other risk factors, while approximately 5% of all CRC cases are purely hereditary.
Hereditary non-polyposis colorectal cancer, also known as Lynch syndrome (LS) accounts for the majority of these hereditary CRC cases (2-3% of overall CRC cases).
Clinical Indication
The CRC gene panel is recommended for patient whose diagnosis and/or family history is indicative of a suspicion of hereditary CRC. Such indications include:
Early age of cancer onset:
- Patient diagnosed with CRC or endometrial cancer at an age < 50
- Patient diagnosed with CRC at an age < 60 and MSI-H histology
Patient presenting multiple cumulative polyps:
- >10 colorectal adenomatous polyps
- Multiple gastrointestinal hamartomatous polyps
Patient with multiple related primary CRCs or other associated LS cancers
Patient fulfilling the revised Bethesda guidelines or from a family meeting the Amsterdam II criteria
Family history:
- Patient with a family history of hereditary CRC, with or without a known mutation
- Multiple close family members with CRC or other associated LS cancers
Test Benefits & Risk Management
The finding of a pathogenic variant will help to relate the clinical phenotype to a precise type of hereditary CRC or related syndrome for which management strategies might be available.
Management options include:
For Lynch Syndrome
Surveillance
- Colon & rectum: Colonoscopy every 1-2 year(s), starting at age 20-25
- Endometrium & ovary: Gynecologic cancer screening
- Others:
› Esophagogastroduodenoscopy (EGD) including side-viewing examination every 1-2 year(s), starting at age 30-35
› Annual urinalysis starting at age 30-35
› Annual physical exam including screening for skin cancers
Prophylactic Surgical Options
- Prophylactic colectomy in young CRC patients
- Prophylactic hysterectomy and/or bilateral salpingo-oophorectomy, after childbearing is completed
For Familial Adenomatous Polyposis (FAP)
Surveillance
- Colon & rectum: Colonoscopy every 1-2 year(s), starting at age 10-12
- Others:
› EGD including side-viewing examination every 1-3 years, starting when colorectal polyposis is diagnosed or at age 20-25
› Annual physical exam including cervical ultrasonography, starting at age 25-30
Prophylactic Surgical Options
- Prophylactic colectomy when polyps become unmanageable
For attenuated Familial Adenomatous Polyposis (aFAP)
Surveillance
- Colon & rectum: Colonoscopy every 2 years, starting at age 18-20
- Others:
› EGD including side-viewing examination every 1-3 years, starting when colorectal polyposis is diagnosed or at age 20-25
› Annual physical exam including cervical ultrasonography, starting at age 25-30
Prophylactic Surgical Options
- Prophylactic colectomy when polyps become unmanageable
For MUTYH-Associated Polyposis
Surveillance
- Colon & rectum: Colonoscopy every 2 years, starting at age 18-20
- Others:
› EGD including side-viewing examination every 1-3 year(s), starting at age 20-25
Prophylactic Surgical Options
- Prophylactic colectomy when polyps become unmanageable
For Peutz-Jeghers syndrome
Surveillance
- Colon & rectum: Colonoscopy every 2-3 years, starting with symptoms or in late teens
- Others:
› EGD including side-viewing examination every 2-3 years, starting at age 10
› Magnetic resonance cholangiopancreatography and/or endoscopic ultrasound of the pancreas every 1–2 years starting at age 30
› Annual mammogram and breast MRI starting at age 25
› Clinical breast exam starting at age 25
› Annual pelvic examination, Pap smear and transvaginal ultrasound starting at age 18 years
› Annual testicular exam starting at age 10
For Juvenile Polyposis syndrome
Surveillance
- Colon & rectum: Colonoscopy every 2-3 years, starting with symptoms or in late teens
- Others:
› Esophagogastroduodenoscopy every 1-3 years