A simplified prognostic system for resected pancreatic neuroendocrine neoplasms

Background: A number of prognostically relevant clinicopathological variables have been proposed for pancreatic neuroendocrine neoplasms. However, a standardized prognostication system has yet to be established for patients undergoing potentially curative tumour resection. Methods: We examined a prospectively maintained, single-institution database to identify patients who underwent potentially curative resection of non-metastatic primary pancreatic neuroendocrine neoplasms. Patient, operative and pathological characteristics were analysed to identify variables associated with disease-specific and disease-free survival. Results: Between 1991 and 2007, 43 patients met inclusion criteria. After a median follow-up of 68 months, 5-year disease-specific survival was 94% and 5-year disease-free survival was 72%. Tumours sized >= 5 cm and vascular invasion were associated with worse disease-specific survival. Tumours sized >= 5 cm, nodal metastases, positive resection margins and perineural invasion were associated with worse disease-free survival. A scoring system consisting of tumour size >= 5 cm, histological grade, nodal metastases and resection margin positivity (SGNM) permitted stratification of disease-specific (P = 0.006) and disease-free (P = 0.0004) survival. This proposed scoring system demonstrated excellent discrimination of individual disease-specific and disease-free survival outcomes as reflected by concordance indices of 0.814 and 0.794, respectively. Conclusions: A simple scoring system utilizing tumour size, histological grade, nodal metastases and resection margin status can be used to stratify outcomes in patients undergoing resection of primary pancreatic neuroendocrine neoplasms.