What is the recommended management for a patient with de novo Familial Adenomatous Polyposis (FAP) diagnosed at 26 years?

Management of De Novo FAP Diagnosed at 26 Years

For a 26-year-old patient with newly diagnosed de novo Familial Adenomatous Polyposis (FAP), prophylactic colectomy is strongly recommended as the primary intervention to prevent the inevitable development of colorectal cancer. 1, 2

Initial Steps After Diagnosis

• Genetic testing should be performed to confirm the APC mutation and allow for mutation-specific testing in family members 3
• Testing for MUTYH mutations should be considered if APC testing is negative 1
• Complete colonoscopy should be performed to assess polyp burden and presence of dysplasia 1
• Upper GI endoscopy should be performed to evaluate for gastroduodenal polyps 3, 4

Surgical Management

Surgical Options:

• Colectomy with ileorectal anastomosis (IRA) - appropriate for patients with:

  • Few rectal adenomas (<15-20) 1
  • Polyp-free rectum 1
  • Desire to preserve fertility 1

• Proctocolectomy with ileal pouch-anal anastomosis (IPAA) - recommended for patients with:

  • Large number of rectal adenomas (>15-20) 1
  • High-grade dysplasia in rectal adenomas 1
  • Severe rectal polyposis 1

Timing of Surgery:

• At 26 years, surgery should be performed promptly as the patient is already beyond the typical age range (16-25 years) for prophylactic surgery 1, 2
• Without surgical intervention, FAP patients almost inevitably develop colorectal cancer by age 40-50 years 1, 5

Post-Surgical Surveillance

After IRA:

• Rectoscopy every 3-6 months depending on severity of rectal adenomas 1
• Lifelong surveillance is essential due to 12-29% risk of cancer in the retained rectum 1, 6

After IPAA:

• Pouchoscopy every 6-12 months 1
• Lifelong surveillance is necessary as adenomas can develop in the pouch (9.4-85% risk) 7, 8

Upper GI Surveillance

• Upper endoscopy every 3 years starting from diagnosis 1, 4
• Both front and side-viewing endoscopes should be used with special attention to the papillary area 4
• Frequency of subsequent screenings should be guided by the Spigelman classification 4

Chemoprevention

• NSAIDs and/or COX-2 inhibitors may reduce colorectal and duodenal adenomas, but their effect on preventing cancer development is unknown 1
• Caution is warranted due to potential cardiovascular side effects 1

Special Considerations

• De novo FAP (no family history) requires genetic counseling for future family planning 1
• Patients should be informed that prophylactic surgery does not eliminate cancer risk completely, as adenomas can develop in the rectal remnant, pouch, or anorectal segment 7, 8
• The cumulative risk of requiring secondary proctectomy after IRA is 70% at 40 years 9

Pitfalls to Avoid

• Delaying surgery is dangerous as the patient is already 26 years old and beyond the recommended age range for prophylactic surgery 2
• Inadequate surveillance after surgery can lead to missed adenomas and cancer development 8
• Assuming complete cancer prevention after surgery - lifelong surveillance remains essential 7, 8