Reappraisal of lymphatic mapping for midgut neuroendocrine patients undergoing cytoreductive surgery.

Background: We previously reported that midgut neuroendocrine tumors (NETs) often develop alternative lymphatic drainage owing to lymphatic obstructions from extensive mesenteric lymphadenopathy, making intraoperative lymphatic mapping mandatory. We hypothesize that this innovative approach needs a longer term validation.

Methods: We updated our results by reviewing 303 patients who underwent cytoreduction from November 2006 to October 2011. Of these patients, 112 had lymphatic mappings and 98 were for midgut NET primaries. Among them, 77 mappings were for the initial cytoreduction and 35 were for reexploration and further cytoreduction. The operative findings, pathology reports, and long-term surgical outcomes were reviewed.

Results: Lymphatic mapping changed traditional resection margins in 92% of patients. Of the 35 patients who underwent reexploration without initial mapping, 19 (54%) showed a recurrence at or near the anastomotic sites. In contrast, none of the 112 mapped patients had shown signs of recurrence in a 1- to 5-year follow-up. Additionally, 20 of 45 ileocecal valves (44.4%) were spared in patients whose tumors were at the terminal ileum that, traditionally, would call for a right hemicolectomy.

Conclusion: With a longer follow-up, lymphatic mapping has proven to be a safe and effective way to prevent local recurrences and preserve the ileocecal valve for selected patients.