What are the preoperative and intraoperative considerations for a patient with a carcinoid tumor undergoing surgery?

Preoperative and Intraoperative Management of Carcinoid Tumor Surgery

Preoperative Assessment

All patients with carcinoid tumors require mandatory preoperative echocardiography to screen for carcinoid heart disease affecting both left and right-sided valves, as 10-30% develop valvular complications including tricuspid regurgitation and pulmonary stenosis 1, 2, 3.

Essential Preoperative Workup

Cardiac Evaluation:

• Echocardiography is non-negotiable before any surgical intervention 2, 3
• Screen specifically for tricuspid regurgitation and pulmonary stenosis, which occur in 10-30% of carcinoid syndrome patients 1

Functional Assessment:

• Perform pulmonary function testing with FEV1 and DLCO measurements to assess surgical risk 2
• If FEV1 or DLCO <80% predicted, proceed with exercise testing and split lung function assessment 2
• Functional respiratory tests must always be performed to assess chronic obstructive airways disease and screen for bronchostenosis 3

Biochemical Markers:

• Obtain baseline 24-hour urine 5-HIAA levels, particularly for small intestinal carcinoids 1
• Measure serum chromogranin A levels (though less specific) 1
• Instruct patients to avoid specific foods (avocados, bananas, cantaloupe, eggplant, pineapples, plums, tomatoes, hickory nuts, plantain, kiwi, dates, grapefruit, honeydew, walnuts) and substances (coffee, alcohol, smoking) for 48 hours before urine collection 1

Imaging:

• Multi-phase CT or MRI to assess disease burden and metastases 1
• Octreoscan (somatostatin receptor scintigraphy) to assess receptor status if octreotide therapy is planned 1

Preoperative Medical Optimization

Prophylactic Cholecystectomy Planning:

• Consider prophylactic cholecystectomy during surgery if long-term octreotide therapy is anticipated, as somatostatin analogs significantly increase risk of biliary symptoms and gallstones 1

Vaccination:

• All patients who might require splenectomy must receive preoperative trivalent vaccine (pneumococcus, haemophilus influenzae b, meningococcal group C) 1

Intraoperative Management

Critical Carcinoid Crisis Prevention

Octreotide must be administered parenterally prior to induction of anesthesia in all patients with functional carcinoid tumors to prevent potentially fatal carcinoid crisis 1, 4.

Octreotide Dosing Protocol:

• Initial dose: 50 mcg administered 2-3 times daily, with upward titration as needed 4
• For carcinoid tumors: 100-600 mcg/day in 2-4 divided doses during initial therapy (mean 300 mcg/day) 4
• In emergency situations (carcinoid crisis): administer by rapid IV bolus 4
• May be diluted in 50-200 mL sterile saline or D5W and infused over 15-30 minutes, or given by IV push over 3 minutes 4

Surgical Principles by Tumor Location

Small Bowel/Jejunum/Ileum/Colon:

• Perform surgical resection with regional lymphadenectomy 1
• Conduct careful examination of entire bowel for synchronous lesions (15-30% incidence) 1
• Resect all palpable regional/mesenteric lymph nodes where feasible 1

Appendiceal Carcinoids:

• Tumors ≤2 cm without aggressive features: simple appendectomy is sufficient 1
• Tumors >2 cm or 1-2 cm with poor prognostic features (lymphovascular invasion, mesoappendiceal invasion, atypical histology): right hemicolectomy 1

Pulmonary Carcinoids:

• For peripheral tumors: complete anatomic resection (lobectomy or segmentectomy) with systematic nodal dissection including minimum 6 nodes/stations, with at least 3 mediastinal nodes including subcarinal station 1, 2, 3
• For central airway tumors: prioritize lung parenchymal-sparing surgery (bronchial sleeve resection or sleeve lobectomy) over pneumonectomy 1, 3
• Avoid wedge resection as it increases local recurrence risk, particularly for atypical carcinoids 2, 3

Gastric Carcinoids:

• Type 1/2 (hypergastrinemic), ≤2 cm: endoscopic resection if feasible 1
• Type 1/2, >2 cm: surgical resection 1
• Type 3 (sporadic, normal gastrin): radical resection with regional lymphadenectomy 1

Intraoperative Complications Management

Carcinoid Crisis Recognition:

• Manifests as severe flushing, bronchospasm, hypotension, or hypertension 5, 6
• Treat immediately with rapid IV bolus octreotide 4, 5
• Have octreotide readily available throughout the procedure 5, 6

Common Pitfalls to Avoid:

• Never manipulate tumor extensively before octreotide administration, as this can precipitate crisis 5, 6
• Do not use medications that trigger histamine release (morphine, atracurium, succinylcholine) 5
• Avoid sympathomimetic agents that may exacerbate symptoms 5

Special Considerations for Metastatic Disease

Hepatic Metastases:

• Liver-directed therapies following pancreatoduodenectomy carry increased risk for perihepatic sepsis and liver abscess 1
• Complete resection of liver metastases achieves >70% 5-year survival when feasible 1
• Cytoreductive surgery (>90% tumor removal) may be considered for symptom control in selected patients 1, 3