Tu1096 Utility of Neuroendocrine Biomarkers in Screening for Occult Familial Midgut Carcinoid Tumor in Asymptomatic High Risk Individuals: Results of a Prospective Study

Abstract

Background: The incidence of gastric neuroendocrine tumors (NETs) has increased ten-fold since the 1970s. The majority of type I gastric NETs arise from enterochromaffin-like cell hyperplasia in the setting of atrophic gastritis and pernicious anemia. Studies on type I gastric NETs have been limited, and consensus over their management and long-term outcomes remains elusive. Aim: The primary aim was to describe the clinicopathologic characteristics, management, and outcome of type I gastric NETs for this patient population at The Mount Sinai Hospital. Methods: From existing databases of the Mount Sinai Division of Gastrointestinal Pathology and the Carcinoid Cancer Foundation, we identified 56 patients with type I gastric NETs seen at The Mount Sinai Hospital from 1993 to 2012. A comprehensive dataset encompassing demographic, clinical, endoscopic and pathologic factors was generated. Overall survival information was determined from medical records and confirmed using the Social Security Death Index. Tumor-Node-Metastasis (TNM) staging was conducted according to tumor size, depth of invasion, presence of nodal involvement and presence of metastasis. Tumors were graded based on mitotic counts and Ki67 index. Statistical analysis was performed using SPSS. Results: The median age was 63.3 years (range: 37.2-89.4); 80.4% were female. Upon initial presentation, 70.3% exhibited abdominal pain and 24.3% unintentional weight loss. Two-thirds and one-third of patients tested positive for parietal cell and intrinsic factor antibodies, respectively, while median gastric pH was 6.9. Median carcinoid size was 3.0 mm (range: 0.8-25.0), with 55.8% displaying multifocal disease (Table 1). Stage I-IV disease was observed in 83.8%, 10.8%, 5.4% and 0%, respectively. Tumors were either low (69.7%) or intermediate (30.3%) grade. Furthermore, 7.3% of patients exhibited gastric dysplasia, whereas 5.5% developed gastric adenocarcinoma. Patients received a mean 1.15 endoscopies per year, while 28.6% underwent polypectomy, 32.7% somatostatin therapy and 46.4% laparoscopic antrectomy (Table 2). The 5and 10-year disease-specific survival rates were 100%. There were two patient deaths unrelated to NET disease. Conclusion: Most type I gastric NET patients developed multiple, small, benign, indolent lesions. The majority of patients underwent EGD surveillance annually, with a minority receiving somatostatin-based or surgical intervention. We discovered a very low but real rate of regional lymph node involvement; however, these occurred in the complete absence of distant metastasis. This was unexpected given the generally indolent behavior of type I gastric NETs. Interestingly, several patients demonstrated concurrent dysplasia or adenocarcinoma, underscoring the efficacy of regular endoscopic management not only for gastric NETs, but also for dysplasia and adenocarcinoma.