Prognostic Value of Lymph Node Status and Lymphadenectomy in Pancreatic Neuroendocrine Tumors

Abstract

Listen

Translate article

Introduction: Lymph node metastasis (LNM) is common in patients with pancreatic neuroendocrine tumors (pNETs) but the prognostic value and optimal management remains controversial. The objective of the current study was to investigate factors associated with LNM and the prognostic value of LNM and lymphadenectomy in pNETs. Method: A total of 1067 patients who underwent resection for pNETs between 1997 and 2016 were identified from the US Neuroendocrine Tumor Study Group. Clinicopathologic data were reviewed and survival analysis was performed to identify the prognostic factors. Result: There were 549 (51.5%) male, and 518 (48.5%) females, with a median age of 58 years (IQR 47-65 years). There were 525 (49.2%) patients with WHO G1 tumor, 257 (24.1%) with G2 and 32 (3.0%) with G3. Lymphadenectomy was performed in 891 (83.5%) patients, and 256 (24.0%) cases were confirmed to be positive. Multivariable analysis revealed that LNM was associated with head/uncinate location (p=0.021), largest tomur size>2cm (p=0.004), increasing tumor grade (p=0.021), lymph vascular invasion (p<0.001) and distant metastasis (p=0.001). With a median follow up of 34.5 months, 144 (13.5%) patients recurred and 124 (11.6%) patients died of disease progression. The median OS of N1 group was 127.2 moths, which was significantly shorter than N0/Nx group (176.4 months, p<0.001). For patients underwent curative resection (R0/R1, n=1012), the median RFS in N0/Nx group was also superior to N1 group (not reached vs. 91.1 months, p<0.001). In addition, number of positive lymph node>5 was associated with worse OS (p=0.013). Lymphadenectomy was mostly performed in distal pancreatectomy (59.9%), tumor size >2cm (89.7%), and grade G3 (93.8%). The median OS in Nx group (190.9 months) was similar to N0 group (176.4 months, p=0.265). Conclusion: LNM are valuable predictor of poor outcomes for pNETs. Surgery without LA is safe in selected patients with small G1 lesions, normal sized and soft lymph nodes.