[751] Ki67 Proliferative Index: A Sensitive Indicator of Prognosis in Gastric Neuroendocrine Neoplasms

Hayriye Tatli Dogan, Aydan Kilicarslan, Serdar Balci, Ozge Basaran Aydogdu, Gulnur Guler. Yildirim Beyazit University, Ankara, Turkey

Background: Gastric neuroendocrine neoplasms (GNEN) display a diverse spectrum of clinical behavior. It is not easy to predict the clinical course of the disease because of wide variation in their potential to metastasize and progress. We aimed to search the association of Ki67 index with tumor size, mitotic rate, presence of lymphovascular invasion and distant metastasis.
Design: A retrospective study was performed by reviewing data for surgically and endoscopically resected GNENs from pathology database between 2007 to 2012. Mitotic count in 10 HPF's and Ki67 proliferation index, as a percentage of 500 cells are counted in areas of strongest nuclear labeling. Grading is reevaluated according to WHO 2010 gastrointestinal NET classification. Localization of the tumor, multifocality, metastasis, lymphovascular invasion, and adjacent intestinal metaplasia are also noted.
Results: 30 GNENs were identified among 80 gastroenteropancreatic neuroendocrine tumors. In GNENs the mean age of the patients was 56,53 ±13,001 (range 31-81). There was a slight female predominance (16 F, 14 M). Intestinal metaplasia and atrophic gastritis were found in 46,7%, multifocality was found in 33% of the cases. 16 (53,3%) of the cases were in corpus, 7 (23,3%) in antrum, 4 (13,3%) in fundus. The localisation of 3 were unknown. 16 (53,3%) of 30 cases were grade 1, 7 (23,3%) grade 2, and 7 (23,3%) poorly differantiated neuroendocrine carcinoma (PDNEC). There was a positive correlation between Ki67 index and mitosis (r2=0.914, p<0.001). We analysed Ki67 index association with different cutoff values. Tumor size was greater (average: 4,8cm) in Ki67>10% group, compared with Ki67< 10% ones (p<0,001). Lymphovascular invasion (LVI) and liver metastasis were seen only in cases with Ki67>2% (p=0,002). 5 of the 6 cases with LVI had >10% Ki67 indices.
Conclusions: Ki67 index is a sensitive indicator of aggressive behaviour. Our data indicate that LVI is seen in 83,3% of patients with Ki67 index >10% whereas in 54% of patients with Ki67 index >2%. Further studies including more patients are needed to test different Ki67 cut off values on prognosis of GNENs.
Category: Gastrointestinal

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 84, Wednesday Afternoon


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