Validation of five contemporary prognostication systems for primary pancreatic endocrine neoplasms: results from a single institution experience with 61 surgically treated cases

Background: Presently, several systems for the prognostication of pancreatic endocrine neoplasms (PENs) exist and the most appropriate classification system has not been clearly defined. This study aims to validate the performance of the 2004 World Health Organization (WHO), European Neuroendocrine Tumor Society (ENETS), Memorial Sloan-Kettering Cancer Center (MSKCC), American Joint Committee for Cancer (AJCC) TNM staging and Bilimoria criteria in a cohort of patients with PENs who underwent surgery at a single institution. Methods: This study is a retrospective review of 61 consecutive patients who underwent surgical treatment for PEN. Actuarial disease-specific survival (DSS) of all 61 patients and recurrence-free survival (RFS) of 53 patients who had curative resection were analysed. Results: On univariate analyses, tumour size >= 50 mm, non-curative resection, lymph node involvement, presence of distant metastases, presence of necrosis, mitotic count >= 2/10 hpf and poor differentiation were associated with decreased DSS. Tumour size >= 50 mm, lymph node involvement, lymphovascular invasion, presence of necrosis and mitotic count >= 2/10 hpf were associated with decreased actuarial RFS. All five staging systems were useful in stratifying the 61 patients according to actuarial DSS. However, the MSKCC grading and ENETS grading systems were not statistically significant in stratifying DSS in the 61 patients. In the 53 patients who underwent curative resection, the WHO, ENETS, MSKCC, AJCC staging and the MSKCC grading systems were successful in stratifying the patients according to actuarial RFS. However, the Bilimoria scoring and ENETS grading systems were not useful in prognosticating these 53 patients. Conclusion: All five classification systems were useful for the prognostication of surgically treated PENs in our patient cohort.