What is the recommended management for an adult with over 100 colonic polyps, a family history of Familial Adenomatous Polyposis (FAP), and a benign lesion on biopsy?

Management of Adult with >100 Colonic Polyps and Family History of FAP

This patient requires immediate prophylactic surgery, specifically proctocolectomy with ileal pouch-anal anastomosis (IPAA), given the presence of >100 polyps consistent with classical FAP and strong family history—surveillance alone is inadequate and dangerous. 1

Why Surgery is Mandatory

• Patients with classical FAP and 100+ colorectal polyps require colectomy without delay to prevent the near-inevitable development of colorectal cancer, which occurs by mean age 40-50 years without surgical intervention 1, 2

• The presence of >100 polyps definitively establishes classical FAP diagnosis, particularly with two first-degree relatives already diagnosed and treated for FAP 3

• Follow-up colonoscopy alone (Option B) is contraindicated as the primary management strategy—this patient has already crossed the threshold requiring definitive surgical intervention 1

Choosing Between Surgical Options

Proctocolectomy with IPAA (Option C) - RECOMMENDED

This is the preferred operation for classical FAP because it removes all at-risk colorectal mucosa and eliminates the 12-29% lifetime risk of rectal cancer that persists after ileorectal anastomosis. 3, 1

• IPAA is specifically indicated when there are >15-20 rectal polyps, which is likely given the >100 total colonic polyps described 1

• The operation achieves excellent long-term functional outcomes with >95% patient satisfaction and is safe with 0.5-1% mortality 4

• Guidelines explicitly state IPAA is "the operation of choice" for FAP "in view of the long-term risk of rectal cancer" 3

Colectomy with IRA (Option A) - NOT RECOMMENDED in this case

• IRA is reserved only for highly selected patients with relative rectal sparing (<20 polyps), all rectal adenomas <5mm, and patients who can commit to lifelong intensive surveillance 1

• The question states "normal rest of the rectum" but does not specify polyp count in the rectum—with >100 total colonic polyps, significant rectal involvement is highly probable 5

• The 12-29% risk of rectal cancer after IRA requires annual lifelong surveillance, and this risk is unacceptable when IPAA can eliminate it 3, 1

• IRA might be considered only if there are truly <5 rectal polyps, but even then IPAA is recommended for the vast majority of FAP patients 4

Critical Decision Algorithm

Choose IPAA if ANY of the following:

• 15-20 rectal polyps 1

• Any rectal polyps >5mm diameter 1
• High-grade dysplasia in any rectal polyp 1
• Patient unlikely to comply with annual lifelong rectal surveillance 1
• Patient preference to eliminate cancer risk completely 3

Consider IRA ONLY if ALL of the following:

• <20 rectal polyps (preferably <5) 1, 4
• All rectal polyps <5mm 1
• No high-grade dysplasia 1
• Patient strongly desires better functional outcomes 1
• Patient can commit to annual lifelong rectoscopy 3

Post-Surgical Surveillance Requirements

After IPAA (if chosen):

• Annual surveillance of the anorectal cuff for life (can be every 1-2 years in some protocols) 1
• Adenomas can still develop in the pouch (8-62% incidence) requiring lifelong monitoring 4

After IRA (if chosen):

• Annual endoscopic examination of retained rectum for life is mandatory 3, 1
• More frequent surveillance (every 6-12 months) if significant rectal polyp burden persists 1

Upper GI Surveillance (regardless of procedure):

• Begin at age 25-30 years with gastroduodenal endoscopy using front and side-view scopes 3, 1
• Frequency based on Spigelman staging of duodenal polyposis 1

Common Pitfalls to Avoid

• Do not delay surgery for "further surveillance"—this patient is already at high risk and surgery should proceed promptly 1, 6

• Do not choose IRA simply because the rectum appears "normal" on visual inspection—polyp count and size must be specifically documented 1

• Do not perform abdominoperineal resection (Miles operation)—this is not recommended for FAP as it requires permanent stoma and discourages family screening 3

• Do not assume benign biopsy means low risk—the sheer number of polyps (>100) drives cancer risk, not individual polyp histology at this point 1, 2