appropriate surgical management for non–PNETS (carcinoid tumors)
- Gastric carcinoids are classified into three types. Types I and II account for most gastric carcinoids (> 75%) and are associated with chronic hypergastrinemia resulting from chronic atrophic gastritis (type I) and ZES (type II), respectively.
- These tumors are most commonly small (< 1 cm) and multifocal and are typically treated by endoscopic resection and surveillance with excellent outcomes.
- Octreotide or lanreotide therapy can control symptoms in patients with type II gastric carcinoids and ZES. Type III gastric carcinoids occur sporadically and are usually larger, solitary, and invasive.
- They are treated similarly to gastric adenocarcinoma with formal gastric resection and lymph node dissection. For tumors < 2 cm in size, endoscopic or wedge resection is possible.
- Small intestinal carcinoids without metastases should be excised by segmental resection and lymph node dissection.
- Some studies advocate the use of prophylactic octreotide (preoperative bolus and/or continuous infusion) during surgery for foregut and midgut carcinoids to prevent carcinoid crisis; however, this remains controversial because some studies have shown it to be ineffective.
- Appendiceal carcinoids are typically incidentally discovered and occur most commonly at the appendiceal tip. Distal lesions < 2 cm are adequately treated with appendectomy.
- The presence of a carcinoid tumor near the appendiceal base, size > 2 cm, or gross lymph node involvement requires a formal right hemicolectomy.
- Rectal carcinoids often manifest with bleeding or are incidentally found on endoscopy.
- Tumors < 1 cm can be subjected to endoscopic resection, tumors 1 to 2 cm to transanal excision, and tumors > 2 cm or with evidence of lymph node metastasis on endoscopic ultrasonography to surgical resection (low anterior resection or abdominoperineal resection).