Recommended Screening Programs for Familial Adenomatous Polyposis (FAP) Patients
FAP patients require comprehensive, lifelong surveillance with specific screening protocols for both colorectal and extracolonic manifestations beginning in early adolescence.
Colorectal Screening
Classical FAP
- Flexible sigmoidoscopy should be performed every 2 years starting at age 12-14 years and continued lifelong in mutation carriers 1
- Once adenomas are detected, colonoscopy should be performed annually 1
- Surgery is indicated when there are large numbers of adenomas or adenomas showing high-grade dysplasia 1
- Prophylactic colorectal surgery is recommended by the late teens or early twenties 2
Attenuated FAP (AFAP)
- Total colonoscopy (not just sigmoidoscopy) should be performed every 2 years starting at age 18-20 years and continued lifelong in mutation carriers 1
- Once adenomas are detected, colonoscopy should be performed annually 1
- Some patients with AFAP can be conservatively managed with annual colonoscopy and polypectomy rather than immediate surgery 1
Extracolonic Manifestations Screening
Upper Gastrointestinal Tract
- Gastroduodenal endoscopy using both front and side-view scopes, with special attention to the papillary area, should be performed every 5 years until adenomas are detected 1
- Screening should start when colorectal polyposis is diagnosed or at age 25-30 years, whichever comes first 1
- Upper endoscopy is necessary for surveillance to reduce the risk of ampullary and duodenal cancer 2
Thyroid Cancer Screening
- Annual cervical ultrasonography is recommended for thyroid cancer screening 1
- This should be included as part of the regular extracolonic manifestation screening protocol 1
Desmoid Tumors
- Regular physical examination and abdominal CT should be performed, especially in patients with a positive family history of desmoids or after abdominal surgery 1
- Desmoids are one of the two main causes of mortality after total colectomy and need to be identified early 2
Genetic Testing Considerations
- Genetic testing should be considered in patients with FAP who have relatives at risk 1
- Full germline genetic testing of APC should include DNA sequencing and large rearrangement analysis 1
- When the APC mutation in the family has been identified, genetic testing of all first-degree relatives should be performed 2
- Genetic counseling should guide genetic testing and considerations of colectomy 1
Post-Surgical Surveillance
- After colorectal surgery, surveillance of the rectum or pouch should be carried out regularly 1
- Annual physical examination is recommended for patients who have undergone surgical management 3
- The decision on the type of colorectal surgery (total colectomy + IRA versus proctocolectomy + IPAA) depends on the age of the patient, severity of rectal polyposis, wish to have children, risk of developing desmoids, and possibly the site of the mutation in the APC gene 1
Importance of Registry Enrollment
- Enrollment in a Polyposis Registry significantly improves survival from 58.1 years to 69.6 years 4
- Registry-managed screening programs have been shown to reduce CRC incidence from 28.7% to 14.0% 4
- Systematic follow-up through registries helps ensure appropriate prophylactic surgery is performed before colorectal cancer develops 4
Common Pitfalls and Caveats
- Delays in treatment often occur due to social factors or fear of surgery, which can lead to preventable colorectal cancers 5
- Colonoscopy alone may not be reliable for detecting malignancy when multiple colorectal polyps are present, emphasizing the importance of prophylactic surgery 5
- Upper endoscopy adherence is suboptimal, with approximately 20% of FAP patients not undergoing recommended upper endoscopy 6
- Genetic testing rates among family members are often low (around 40%), highlighting the need for better family education and follow-up 6