Strong evidence comparing different treatment options for liver metastases (LM) arising from gastroenteropancreatic neuroendocrine tumours (GEP-NET) is lacking. The aim of this study was to determine which intervention for LMs from GEP-NETs shows the longest overall survival (OS). A systematic search was performed in MEDLINE, Embase and the Cochrane Library in February 2018. Studies reporting on patients with LMs of any grade of sporadic GEP-NET comparing two intervention groups were included for analysis. Meta-analyses were performed where possible. Eleven studies, with a total of 1108, patients were included; 662 patients had LM from pancreatic NETs (pNET), 164 patients from small-bowel NETs (SB-NET) and 282 patients of unknown origin. Improved 5-year OS was observed for surgery vs. chemotherapy (OR 0.05 95% CI [0.01, 0.21] p < 0.0001), for surgery vs. embolization (OR 0.18 95% CI [0.05, 0.61] p = 0.006) and for LM resection vs. no LM resection (OR 0.15 95% CI [0.05, 0.42] p = 0.0003). This is the largest meta-analysis performed comparing different interventions for LMs from GEP-NETs. Despite the high risk of bias and heterogeneity of data, surgical resection for all tumour grades results in the longest overall survival. Chemotherapy and embolization should be considered as an alternative in case surgery is not feasible.

Although small bowel resection is generally considered a low risk gastrointestinal procedure, this might not be true for small bowel neuroendocrine neoplasms (SB‐NEN) as a result of potential central mesenteric involvement. We aimed to determine the reported morbidity and mortality after resection of SB‐NEN in the literature and assess the effect of hospital volume on postoperative morbidity and mortality. A systematic review was performed by searching MEDLINE and Embase in March 2021. All studies reporting morbidity and/or mortality after SB‐NEN resection were included. Pooled proportions of overall morbidity (Clavien‐Dindo I‐IV), severe morbidity (Clavien‐Dindo III‐IV), 30‐day mortality, 90‐day mortality and in‐hospital mortality were calculated, as well as the association with hospital volume (high volume defined as the fourth quartile). Thirteen studies were included, with a total of 1087 patients. Pooled proportions revealed an overall morbidity of 13% (95% confidence interval [CI] = 7%‐24%, I² = 90%), severe morbidity of 7% (95% CI = 4%‐14%, I² = 70%), 30‐day mortality of 2% (95% CI = 1%‐3%, I² = 0%), 90‐day mortality of2% (95% CI = 2%‐4%, I² = 35%) and in‐hospital mortality of 1% (95% CI = 0%‐2%, I² = 0%). An annual hospital volume of nine or more resections was associated with lower overall and severe morbidity compared to lower volume: 10% vs 15% and 4% vs 9%, respectively. Thirty‐day mortality was similar (2% vs 1%) and 90‐day mortality was higher in high‐volume hospitals: 4% vs 1%. This systematic review with meta‐analyses showed severe morbidity of 7% and low mortality rates after resection of SB‐NEN. The currently available literature suggests a certain impact of hospital volume on postoperative outcomes, although heterogeneity among the included studies constrains interpretation.

Although minimally invasive surgery is becoming the standard technique in gastrointestinal surgery, implementation for small bowel neuroendocrine neoplasms (SB-NEN) is lagging behind. The aim of this international survey was to gain insights into attitudes towards minimally invasive surgery for resection of SB-NEN and current practices. An anonymous survey was sent to surgeons between February and May 2021 via (neuro)endocrine and colorectal societies worldwide. The survey consisted of questions regarding experience of the surgeon with minimally invasive SB-NEN resection and training. A total of 58 responses from five societies across 20 countries were included. Forty-one (71%) respondents worked at academic centers. Thirty-seven (64%) practiced colorectal surgery, 24 (41%) endocrine surgery and 45 (78%) had experience in advanced minimally invasive surgery. An open, laparoscopic or robotic approach was preferred by 23 (42%), 24 (44%), and 8 (15%) respondents, respectively. Reasons to opt for a minimally invasive approach were mainly related to peri-operative benefits, while an open approach was preferred for optimal mesenteric lymphadenectomy and tactile feedback. Additional training in minimally invasive SB-NEN resection was welcomed by 29 (52%) respondents. Forty-three (74%) respondents were interested in collaborating in future studies, with a cumulative median (IQR) annual case load of 172 (86-258). Among respondents, 69% applies minimally invasive surgery for resection of SB-NEN. Arguments for specific operative approaches differ, and insufficient training in advanced laparoscopic techniques seems to be a barrier. Future collaborative studies can provide better insight in selection criteria and optimal technique.

Recommendations for resection technique of duodenal neuroendocrine neoplasms (D-NEN) with a size between 10 and 20 mm are lacking. The primary aim was to compare overall survival (OS) and progression-free survival (PFS) after endoscopic resection (ER) with surgical resection (SR). The secondary aim was to assess the incidence and clinical variables correlated with OS. Data of patients with D-NENs between 2008 and 2018 were extracted from the Netherlands Cancer Registry and the Dutch Nationwide Pathology Databank. A total of 259 patients were identified, of which 138 were included: 98 (68 %) underwent ER and 44 patients (32 %) underwent SR. Of these, 38 patients had D-NENs sized between 10 and 20 mm. ER Patients were more frequently male and had a lower T-stage and tumour size than SR patients (all P < 0.05). Positive resection margins were observed more frequently after ER compared to SR (71 % vs 15 %, P < 0.005). No patients with tumours between 10 and 20 mm died after ER or SR (median follow-up 71.8 vs. 52.0 months). PFS rates were not significantly different after ER compared to SR (P = 0.672). Recurrence rates were 13 % for ER and 7 % for SR (P = 0.604). Between 2008 and 2018, the incidence increased from 0.06 to 0.11 per 100,000 patients per year. OS after ER or SR did not differ for D-NEN between 10 and 20 mm. Recurrence and PFS rates were not significantly different. These results suggest that D-NENs sized between 10 and 20 mm could potentially be treated first with ER. Future studies are needed to confirm this hypothesis.