Surgical resection of primary tumor is associated with prolonged survival in low-grade pancreatic neuroendocrine tumors

Introduction. - The incidence of pancreatic neuroendocrine tumors (PNETs) is increasing over the past few decades. Surgery for low-grade and small PNETs of less than 2 cm and N0M0 is still debated. The purpose of this study is to examine the association between surgical resection and survival in patients with low-grade nonfunctioning PNETs. Materials and methods. - Patients diagnosed with PNETs between 2004 and 2015 were extracted from SEER. Kaplan-Meier methods and Cox proportional hazard models were used to estimate independent predictors in PNETs patients. Results. - A total of 2637 patients (2147 underwent surgical resection and 490 did not undergo surgery) with histologically confirmed low-grade PNETs in this cohort study. Overall survival (OS) and cancer-specific survival (CSS) of patients with surgery was better than those without surgery (log rank test POS < 0.001, PCSS < 0.001). Multivariate Cox regression analysis showed that surgical status was an independent prognostic factor associated with OS (HR 3.257, 95%CI: 2.635, 4.026) and CSS (HR 3.546, 95%CI: 2.798, 4.493). Subgroup analysis suggested the patients receiving surgery apparently had better OS and CSS regardless of tumor size (all log rank test POS < 0.001, all log rank test PCSS < 0.001) and SEER stage (all log rank test POS < 0.001, all log rank test PCSS < 0.001), compared to patients without removal of the primary tumor. <comment>Superscript/Subscript Available</comment> ABSTRACT Summary Introduction. - The incidence of pancreatic neuroendocrine tumors (PNETs) is increasing over the past few decades. Surgery for low-grade and small PNETs of less than 2 cm and N0M0 is still debated. The purpose of this study is to examine the association between surgical resection and survival in patients with low-grade nonfunctioning PNETs. Materials and methods. - Patients diagnosed with PNETs between 2004 and 2015 were extracted from SEER. Kaplan-Meier methods and Cox proportional hazard models were used to estimate independent predictors in PNETs patients. Results. - A total of 2637 patients (2147 underwent surgical resection and 490 did not undergo surgery) with histologically confirmed low-grade PNETs in this cohort study. Overall survival (OS) and cancer-specific survival (CSS) of patients with surgery was better than those without surgery (log rank test POS < 0.001, PCSS < 0.001). Multivariate Cox regression analysis showed that surgical status was an independent prognostic factor associated with OS (HR 3.257, 95%CI: 2.635, 4.026) and CSS (HR 3.546, 95%CI: 2.798, 4.493). Subgroup analysis suggested the patients receiving surgery apparently had better OS and CSS regardless of tumor size (all log rank test POS < 0.001, all log rank test PCSS < 0.001) and SEER stage (all log rank test POS < 0.001, all log rank test PCSS < 0.001), compared to patients without removal of the primary tumor. Conclusions. - Surgical resection of primary tumor may have a significant benefit on survival for patients with low-grade nonfunctioning PNETs. To determine the optimal management, grade, stage and tumor size should be considered comprehensively. (c) 2020 L'Auteur(s). Publi ' e par Elsevier Masson SAS. Cet article est publi ' e en Open Access sous licence CC BY-NC-ND (http://creativecommons.org/licenses/by-nc-nd/4.0/).