[763] Ileal 'Carcinoid' Tumours – Small Size Belies Deadly Intent: High Rate of Nodal Metastasis in Tumours ≤1cm

Joanna C Walsh, David F Schaeffer, Marco Manzoni, Aaron Pollett, Richard Kirsch, Robert H Riddell, Luca Albarello. Mount Sinai Hospital, Toronto, ON, Canada; San Raffaele Scientific Institute, Milan, Italy

Background: Neuroendocrine ('carcinoid') tumours account for 2% of tumours of the GI tract, most occurring in the small intestine. A size of 2cm is generally regarded as a cut off point for risk of lymph node metastasis in intestinal neuroendocrine tumours in the absence of other high risk features. However, metastatic disease has been reported in 12% in tumours of the jejunum and ileum measuring 1cm or less.
Design: Archives from 2 institutions were searched for ileal neuroendocrine tumours measuring 1cm or less. Gross, histologic, demographic, clinical and follow-up data were recorded.
Results: Twenty-one ileal neuroendocrine tumours were identified measuring ≤10mm (mean 6.5 mm (range 1-10mm), male:female ratio 11:10, mean age 64y (range 36-90y)). At least 6 cases were incidental findings either at colonoscopy or at surgery for other causes. Seven (33%) were multiple and 19 (90%) met the WHO criteria for well differentiated neuroendocrine carcinoma. Regional lymph nodes were examined in 14 cases (67%) and 10 of these cases (71%) showed lymph node metastasis (mean number of nodes examined 8.79 (range 1-25), mean number of positive nodes 2.36 (range 1-11)). Mean primary tumour size in cases with nodal metastasis was 7.3mm (range 3-10mm) and 4 (29%) were multifocal. Seven (33%) had distant metastasis at diagnosis (6 liver, 1 mesentery). Follow up data were available for 17 patients (81%) with a mean follow up period of 39 months (range 1-135 months). Four patients (19%) were dead from disease, 8 (38%) were dead from other causes, 3 (14%) were alive without disease at last follow up and 2 (10%) were alive with disease.
Conclusions: In this series of ileal neuroendocrine tumors ≤1cm in size, the rate of lymph node metastasis was 48% overall and 71% for cases with regional lymph node resections. In addition, 33% showed distant metastasis at the time of diagnosis (possible referral bias). It is apparent that tumours as small as 3mm and those confined to the submucosa can give rise to lymph node metastasis. These data emphasise the need for serious consideration of local resection with regional lymphadenectomy, even for sub-centimetre ileal neuroendocrine tumours.
Category: Gastrointestinal

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 74, Wednesday Morning


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