Lymphatic mapping helps to define resection margins for midgut carcinoids

Background: The extensive mesenteric lymphadenopathy associated with midgut carcinoids often causes lymphatic obstruction and leads to the development of alternative lymphatic drainage pathways. We hypothesized that altered lymphatic drainage makes traditional determination of resection margins inadequate. Methods: One hundred and seventy patients underwent cytoreductive surgery for neuroendocrine tumors from November 2006 to August 2008. Forty-nine patients underwent intra-operative lymphatic mapping with lymphazurin dye as a single agent. Twenty-seven patients had midgut primaries. We reviewed operative findings and pathology to evaluate the safety and efficacy of lymphatic mapping for midgut carcinoids. Lymphatic mapping defined resection margins were compared to traditional surgical margins. Results: There were no adverse events associated with the 49 lymphatic mapping procedures. Twenty-five (92%) patients had ileal and 2 had jejunal primaries. Lymphatic mapping changed traditional resection margins in 88% of patients. We preserved the ileocecal valve in 6 of 15 (40%) of patients with terminal ileal primaries. Conclusion: Lymphatic mapping seems to be a safe, time efficient, and effective way to determine adequate resection margins for midgut carcinoids. We advocate using lymphatic mapping for patients with midgut carcinoids to identify adequate resection margins and assist in preservation of the ileocecal valve in patients with terminal ileal primary carcinoids.