Impact of tumor size and nodal status on recurrence of nonfunctional pancreatic neuroendocrine tumors ≤2 cm after curative resection: A multi‐institutional study of 392 cases

Abstract

Background: The current study sought to define the impact of lymph node metastasis (LNM) relative to tumor size on tumor recurrence after curative resection for nonfunctional pancreatic neuroendocrine tumors (NF-pNETs) ≤2 cm.Methods: Patients who underwent curative resection for ≤2-cm NF-pNETs were identified from a multi-institutional database. Risk factors associated with tumor recurrence as well as LNM were identified. Recurrence-free survival (RFS) was compared among patients with or without LNM.Results: A total of 392 ≤2-cm NF-pNETs patients were identified. Among the 328 patients who had lymph node dissection and evaluation, 42 (12.8%) patients had LNM. LNM was associated with tumor recurrence (hazard ratio, 3.06; P = .026) after surgery. RFS was worse among LNM vs no LNM patients (5-year RFS, 81.7% vs 94.1%; P = .019). Patients with tumors measuring 1.5-2 cm had a two-fold increase in the incidence of LNM vs patients with tumors <1.5 cm (17.9% vs 8.7%, odds ratio, 2.59; P = .022), as well as a higher risk of advanced tumor grade and higher Ki-67 levels (both P < .01). After curative resection, a total of 14 (8.0%) patients with a tumor of 1.5-2 cm and 10 (4.5%) patients with tumor <1.5 cm developed tumor recurrence.Conclusion: Surgical resection with lymphadenectomy should be considered for patients with NF-pNETs ≥1.5-2.0 cm. K E Y W O R D S lymph node metastasis, neuroendocrine tumor, pancreas, surgery, tumor size Ding-Hui Dong and Xu-Feng Zhang contributed equally to this work.

Risk of malignancy and prognosis of sporadic resected small (≤2 cm) nonfunctional pancreatic neuroendocrine tumors

“…Also, regarding long-term pancreatic function, the rates of postoperative endocrine and exocrine pancreatic insufficiency in the present study were similar to those reported by others (23,33). According to previously published studies, the recurrence rate of small NF-PNETs that underwent curative resection ranged from 5.4% to 11% (18,20,28), consistent with our study (7.1%). Taken together, patients with small NF-PNETs can be considered for surgical management, which is considered the only possible cure for NF-PNETs; surgical resection can provide a very high cure rate for small NF-PNETs, with good postoperative and long-term outcomes.…”

“…Further, tumor size was not significantly correlated with the risk of malignancy in the multivariate analysis. The smallest tumor size with malignancy was 1.5 cm in our study, similar to those reported previously (18,27). Alternative tumor size cutoff points have been shown to effectively discriminate between benign and malignant NF-PNETs (20,23,28).…”

Resection of Non-Functional Pancreatic Neuroendocrine Neoplasms—A Single-Center Retrospective Outcome Analysis

“…The option of a limited resection seems to be reserved for patients with a small pNEN. This applies primarily to G1 pNEN, but also to G2 pNEN; here, the adequate preoperative staging, including the exclusion of lymphoid metastasis, is of great importance [27][28][29].…”

Prognosis analysis of patients with pancreatic neuroendocrine tumors after surgical resection and the application of enucleation

“…The case data were derived from the SEER database of the National Cancer Institute of the USA, using the SEER stat software (version 8.3.6), and the reference number was 11706-Nov2019. This database covers approximately 30.0% of cancer cases in the US population and provides clinical workers with first-hand data about cancer epidemiology, clinical features, treatment information, and outcomes [3]. All of the pNETs cases were diagnosed from 2004 to 2017.…”

“…Pancreatic neuroendocrine tumors (pNETs) constitute approximately about 3-5% of the total number of pancreatic tumors, and these tumors exhibit high heterogeneity. Compared with pancreatic adenocarcinomas, pNETs are relatively slow growing but have the potential to be malignant and develop distant metastases, most commonly in the liver [3]. In recent years, the incidence of pNETs in the population has shown a continuous upward tendency.…”