What is the recommended management approach for appendicular neoplasms?

Management of Appendicular Neoplasms

For appendicular neoplasms, surgical management should be based primarily on tumor size, with simple appendectomy sufficient for well-differentiated tumors <2 cm confined to the appendix, while right hemicolectomy is indicated for tumors ≥2 cm or those with high-risk features. 1, 2

Management Algorithm Based on Tumor Size and Features

For Tumors <2 cm

• Simple appendectomy is sufficient for most appendiceal neuroendocrine tumors (NETs) ≤2 cm confined to the appendix with well-differentiated histology, as metastases are uncommon 1
• For tumors 1-2 cm with poor prognostic features (lymphovascular invasion, mesoappendiceal invasion, or atypical histologic features), more aggressive treatment should be considered 1, 2
• For appendiceal NETs <1 cm confined to the appendix without adverse features, simple appendectomy is likely curative 2

For Tumors ≥2 cm

• Right hemicolectomy is indicated due to higher risk of locoregional or distant metastases 1, 3
• Staging with abdominal/pelvic CT or MRI scans should be performed to rule out distant disease 1
• If no distant disease is identified, proceed with right hemicolectomy 1

For Incomplete Resection

• Patients with incomplete resection should undergo staging with abdominal/pelvic CT or MRI scans 1
• If no distant disease is identified, reexploration with right hemicolectomy is recommended 1

Special Considerations

For Adenocarcinoid or Goblet Cell Carcinoid

• These tumors should be managed according to colon cancer guidelines due to their more aggressive behavior 1
• Right hemicolectomy is recommended as the treatment of choice for these tumors 3
• These tumors have a high incidence of synchronous and metachronous colorectal cancer 4

For Patients ≥40 Years with Complicated Appendicitis

• The incidence of appendicular neoplasms is high (3-17%) in adult patients ≥40 years with complicated appendicitis 1
• For patients ≥40 years treated non-operatively for appendicitis, both colonic screening with colonoscopy and interval full-dose contrast-enhanced CT scan are recommended 1
• A recent RCT found a 17% rate of neoplasm in patients older than 40 years with periappendicular abscess 1

Surveillance Recommendations

• For patients with resected appendiceal NETs, follow-up should include complete history and physical examination and consideration of multiphasic CT or MRI (abdominal/pelvic) 1
• Most patients should be reevaluated 3-12 months after resection (earlier if symptomatic) and then every 6-12 months for up to 10 years 1
• Chromogranin A may be used as a tumor marker; elevated levels have been associated with recurrence (category 3 recommendation) 1
• 5-HIAA in a 24-hour urine sample may also be considered as a biochemical marker in some cases 1

Common Pitfalls to Avoid

• Underestimating the risk of lymph node metastases in appendiceal NETs <2 cm with aggressive histologic features 1
• Failing to perform adequate staging for patients with tumors ≥2 cm or incomplete resection 1
• Not considering right hemicolectomy for adenocarcinoid or goblet cell carcinoid tumors, which have more aggressive behavior 1, 3
• Overlooking the high incidence of synchronous and metachronous colorectal cancer in patients with appendiceal tumors 4
• Neglecting to consider interval appendectomy in patients ≥40 years with complicated appendicitis treated non-operatively, given the high rate of neoplasm in this population 1