Surveillance strategy for small asymptomatic non-functional pancreatic neuroendocrine tumors – a systematic review and meta-analysis

Background Non-functional pancreatic neuroendocrine tumors (NF-PNET) are rare neoplasms being increasingly diagnosed. Surgical treatment or expectant management are both suggested for small NF-PNETs. The aim of this study was to evaluate the outcome of surveillance strategy for small NF-PNETs. Methods A systematic search was performed up to March 2016 in MEDLINE, EMBASE and the Cochrane Library according to the PRISMA guidelines. Data was pooled using the random-effects model. Results Nine articles including 344 patients with sporadic and 64 patients with MEN1 related NF-PNET were selected. Tumor growth was observed in 22% and 52%, development of metastases were reported on 0% and 9%, and rate of secondary surgical resection was 12% and 25% in patients with sporadic or MEN1 related NF-PNETs, respectively. All metastases (1 distant, 4 nodal) were reported by a single study in patients with MEN1. Reason for secondary surgery was tumor growth in half of patients undergoing surgery. Discussion Expectant management of small asymptomatic, sporadic, NF-PNETs could be a reasonable option in highly selected patients. However, the level of evidence is low and longer follow-up is needed to identify patients could benefit from upfront surgery instead of expectant treatment

Pancreatic stump closure techniques and pancreatic fistula formation after distal pancreatectomy: Meta-analysis and single-center experience

<div><p>Background</p><p>Pancreatic fistula/PF is the most frequent and feared complication after distal pancreatectomy/DP. However, the safest technique of pancreatic stump closure remains an ongoing debate. Here, we aimed to compare the safety of different pancreatic stump closure techniques for preventing PF during DP.</p><p>Methods</p><p>We performed a PRISMA-based meta-analysis of all relevant studies that compared at least two techniques of stump closure during DP with regard to PF rates/PFR. We further performed a retrospective analysis of our institutional PFR in correlation with stump closure techniques.</p><p>Results</p><p>8301 studies were initially identified. From these, ten randomized controlled trials/RCTs, eleven prospective and 59 retrospective studies were eligible. Stapler closure (26%vs.31%, OR:0.73, <i>p</i> = 0.02), combination of stapler and suture (30%vs.33%, OR:0.70, <i>p</i> = 0.05), or stump anastomosis (14%vs.28%, OR:0.51, <i>p</i> = 0.02) were associated with lower PFR than suture closure alone. Spleen preservation/splenectomy, or laparoscopic/open DP, TachoSil^®, fibrin-like glue-application, or bioabsorbable-stapler-reinforcements (Seamguard^®) did not influence PFR after DP. In contrast, autologous patches (falciform ligament/seromuscular patches) resulted in lower PFR than no patch application (21.9%vs.25,8%, OR:0.60, <i>p</i> = 0.006). In our institution, the major three techniques of stump closure resulted in comparable PFR (suture:27%, stapler:29%, or combination:24%). However, selective suturing/clipping of the main pancreatic duct during pancreatic stump closure prevented severe PF (<i>p</i> = 0.02).</p><p>Conclusion</p><p>After DP, stapler closure, pancreatic anastomosis, or falciform/seromuscular patches lead to lower PFR than suture closure alone. However, the differences are rather small, and further RCTs are needed to test these effects. Selective closure of the main pancreatic duct during stump closure may prevent severe PF.</p></div

Flowchart of the systematic review and meta-analysis.

<p>The boxes to the right indicate the number of excluded studies with the specified reasons.</p

Impact of spleen-preservation and laparoscopic approach on PF rates after DP.

<p><b>A.</b> Forrest plot of studies that provided comparative data on overall (upper plot) and clinically relevant (grade B/C, lower plot) PF rates after either spleen-preserving or spleen-resecting DP. <b>B.</b> The Forrest plot of studies that compared overall (upper plot) and clinically relevant (grade B/C, lower plot) PF rates after laparoscopic vs. open DP, showing no difference in PF probability after either approach. Bottom right: Funnel plot of the included studies in the comparison of laparoscopic vs. open DP with regard to PF rates. Studies that were associated with high PF rates after laparoscopic DP seem to be lacking.</p