Comparison of clinical outcomes between enucleation and regular pancreatectomy in patients with non-functional pancreatic neuroendocrine tumors: a retrospective multicenter and propensity score-matched study

Robotic-assisted pancreatic enucleation: Posterior uncinate approach

Functional pancreatic neuroendocrine tumors (pNET) necessitate surgical resection. Enucleation is the preferred surgical method for well-differentiated pNETs that measure less than 2 cm in diameter, as it offers a greater likelihood of enhancing post-operative recovery and decreasing morbidity and mortality. Insulinomas are particularly suitable for enucleation when such a procedure is viable. However, enucleating tumors within the uncinate process of the pancreas, especially on its posterior aspect, can present substantial challenges. The accompanying video illustrates a robotic-assisted enucleation of an insulinoma in the uncinate process, performed on a 41-year-old male with recurrent hypoglycemia. This intervention led to the resolution of symptoms and incurred minimal post-operative morbidity.

Impact of Regional Metastasis on Survival for Patients with Nonfunctional Pancreatic Neuroendocrine Tumors: A Systematic Review

BACKGROUND

Controversy exists regarding the benefit of lymphadenectomy for nonfunctional pancreatic neuroendocrine tumors (NF-PNET).

PATIENTS AND METHODS

MEDLINE/PubMed, EMBASE, and the Cochrane Library were searched for studies of pancreatic neuroendocrine tumors (PNET) published between 1990 and 2021. Studies of functional PNET were excluded. Reported incidence of lymph node metastasis (LNM) and survival analysis of either disease-free survival (DFS) or overall survival (OS) were required for inclusion.

RESULTS

Overall, 52 studies analyzing 24,608 PNET met the inclusion criteria. The reported LNM rate for NF-PNET ranged from 7 to 64 % (median 24.5%). Reported LNM rates ranged from 7 to 51% (median 11%) for NF-PNET< 2 cm in 14 studies and 29-47% (median 38%) in NF-PNET > 2 cm. In total, 19 studies (66%) reported LNM to have a negative impact on DFS. Additionally, 21 studies (60%) reported LNM to have a negative impact on OS. Two studies investigating the impact of lymphadenectomy (LND) found LND had the greatest impact for large, high-grade tumors. The overall quality of available evidence was low as assessed by the Grading of Recommendations, Assessment, Development, and Evaluation System.

CONCLUSIONS

Published literature evaluating the impact of regional LNM and LND in PNET is confounded by heterogeneity in practice patterns and the retrospective nature of these cohort studies. Most studies suggest high rates of LNM in NF-PNET that negatively impact DFS and OS. Given the high rate of LNM in NF-PNET and its potential detrimental effect on DFS and OS, we recommend lymphadenectomy be completed for NF-PNET > 2 cm and strongly considered for NF-PNET < 2 cm.

The diagnostic value of intravoxel incoherent motion diffusion-weighted imaging for distinguishing nonhypervascular pancreatic neuroendocrine tumors from pancreatic ductal adenocarcinomas

PURPOSE

To primarily evaluate the diagnostic performance of the monoexponential and intravoxel incoherent motion (IVIM) diffusion weighted imaging (DWI) models for differentiating between nonhypervascular pancreatic neuroendocrine tumors (PNETs) and pancreatic ductal adenocarcinomas (PDACs).

METHODS

63 patients with PNETs (35 nonhypervascular PNETs and 28 hypervascular PNETs) and 164 patients with PDACs were retrospectively enrolled in the study and underwent multiple b-value DWI. Intraobserver and interobserver reliabilities of DWI parameters were assessed by using the intraclass correlation coefficient (ICC). The parameters of apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) of nonhypervascular PNETs were compared with PDACs and hypervascular PNETs using the independent sample t test or the Mann-Whitney U test. The diagnostic performance was evaluated using receiver operating characteristic (ROC) analysis.

RESULTS

All DWI parameters values showed good to excellent intra- and interobserver agreements (ICC = 0.743-0.873). Nonhypervascular PNETs had significantly lower ADC and D, but significantly higher f than PDACs (P = 0.005, P < 0.001 and P < 0.001, respectively). ADC, D and f of nonhypervascular PNETs were lower than hypervascular PNETs (P = 0.001, <0.001 and 0.093, respectively). D* of nonhypervascular PNETs showed no statistically significant differences with PDACs and hypervascular PNETs (P = 0.809 and 0.420). D showed a higher area under the curve (AUC), followed by ADC and f (AUC = 0.885, 0.665 and 0.740, respectively) in differentiating nonhypervascular PNETs from PDACs.

CONCLUSION

Monoexponential and IVIM diffusion models are valuable to differentiate nonhypervascular PNETs from PDACs. D showed better performance than f and ADC.

Comparison of Outcomes of Enucleation vs. Standard Surgical Resection for Pancreatic Neoplasms: A Systematic Review and Meta-Analysis

Background

With advancement in health technology, the detection rate of pancreatic neoplasms is increasing. Tissue sparing surgery (enucleation) as well as standard surgical resection are two commonly used modalities of management. There are studies comparing clinical outcomes between these two modalities; however, there is lack of studies that systematically pool the available findings to present conclusive and reliable evidence.

Methods

A systematic search was conducted using the PubMed, Scopus, and Google Scholar databases. Studies that were randomised controlled trials or cohort based or analysed retrospective data were considered for inclusion. Studies should have been done in adult patients with pancreatic neoplasms and should have examined the outcomes of interest by the two management modalities i.e., enucleation and standard surgical resection. Statistical analysis was performed using STATA software.

Results

A total of 20 studies were included in the meta-analysis. The operation time (in minutes) (WMD −78.20; 95% CI: −89.47, −66.93) and blood loss (in ml) (WMD −204.30; 95% CI: −281.70, −126.90) for enucleation was significantly lesser than standard surgical resection. The risk of endocrine (RR 0.32; 95% CI: 0.18, 0.56) and exocrine insufficiency (RR 0.16; 95% CI: 0.07, 0.34) was lower whereas the risk of post-operative pancreatic fistula (RR 1.46; 95% CI: 1.22, 1.75) was higher in enucleation, compared to standard surgical resection group. There were no differences in the risk of reoperation, readmission, recurrence, mortality within 90 days and 5-years overall mortality between the two groups.

Conclusions

Enucleation, compared to standard surgical resection, was associated with better clinical outcomes and therefore, might be considered for selected pancreatic neoplasms. There is a need for randomised controlled trials to document the efficacy of these two management techniques.

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

Surgery remains the only curative treatment of pancreatic neuroendocrine neoplasms (pNEN). Here, we report the outcome after surgery for non-functional pNEN at a European Neuroendocrine Tumor Society (ENETS) center in Germany between 2000 and 2019; cases were analyzed for surgical (Clavien–Dindo classification; CDc) and oncological outcomes. Forty-nine patients (tumor grading G1 n = 25, G2 n = 22, G3 n = 2), with a median age of 56 years, were included. Severe complications (CDc ≥ grade 3b) occurred in 11 patients (22.4%) and type B/C pancreatic fistulas (POPFs) occurred in 5 patients (10.2%); in-hospital mortality was 2% (n = 1). Six of seven patients with tumor recurrence (14.3%) had G2 tumors in the pancreatic body/tail. The median survival was 5.7 years (68 months; [1–228 months]). Neither the occurrence (p = 0.683) nor the severity of complications had an influence on the relapse behavior (p = 0.086). This also applied for a POPF (≥B, p = 0.609). G2 pNEN patients (n = 22) with and without tumor recurrence had similar median tumor sizes (4 cm and 3.9 cm, respectively). Five of the six relapsed G2 patients (83.3%) had tumor-positive lymph nodes (N+); all G2 pNEN patients with recurrence had initially been treated with distal pancreatic resection. Pancreatic resections for pNEN are safe but associated with relevant postoperative morbidity. Future studies are needed to evaluate suitable resection strategies for G2 pNEN.