Postoperative morbidity and mortality after surgical resection of small bowel neuroendocrine neoplasms: A systematic review and meta-analysis

European Neuroendocrine Tumor Society (ENETS) 2024 guidance paper for the management of well-differentiated small intestine neuroendocrine tumours

Both the incidence and prevalence of well-differentiated neuroendocrine tumours from the small intestine (Si-NET) are gradually increasing. Most patients have non-functioning tumours with subtle GI symptoms and tumours are often discovered incidentally by endoscopy or at advanced disease stages by imaging depicting mesenteric lymph node and /or liver metastases while around 30% of the patients present with symptoms of the carcinoid syndrome. Adequate biochemical assessment and staging including functional imaging is crucial for treatment-related decision-making that should take place in an expert multidisciplinary team setting. Preferably, patients should be referred to specialised ENETS Centres of Excellence or centres of high expertise in the field. This guidance paper provides the current evidence and best knowledge for the management of Si-NET grade (G) 1-3 following 10 key questions of practical relevance for the diagnostic and therapeutic decision making.

Radio-Guided Surgery with a New-Generation β-Probe for Radiolabeled Somatostatin Analog, in Patients with Small Intestinal Neuroendocrine Tumors

BACKGROUND

Radio-guided surgery (RGS) holds promise for improving surgical outcomes in neuroendocrine tumors (NETs). Previous studies showed low specificity (SP) using γ-probes to detect radiation emitted by radio-labeled somatostatin analogs.

OBJECTIVE

We aimed to assess the sensitivity (SE) and SP of the intraoperative RGS approach using a β-probe with a per-lesion analysis, while assessing safety and feasibility as secondary objectives.

METHODS

This prospective, single-arm, single-center, phase II trial (NCT05448157) enrolled 20 patients diagnosed with small intestine NETs (SI-NETs) with positive lesions detected at 68Ga-DOTA-TOC positron emission tomography/computed tomography (PET/CT). Patients received an intravenous injection of 1.1 MBq/Kg of 68Ga-DOTA-TOC 10 min prior to surgery. In vivo measurements were conducted using a β-probe. Receiver operating characteristic (ROC) analysis was performed, with the tumor-to-background ratio (TBR) as the independent variable and pathology result (cancer vs. non-cancer) as the dependent variable. The area under the curve (AUC), optimal TBR, and absorbed dose for the surgery staff were reported.

RESULTS

The intraoperative RGS approach was feasible in all cases without adverse effects. Of 134 specimens, the AUC was 0.928, with a TBR cut-off of 1.35 yielding 89.3% SE and 86.4% SP. The median absorbed dose for the surgery staff was 30 µSv (range 12-41 µSv).

CONCLUSION

This study reports optimal accuracy in detecting lesions of SI-NETs using the intraoperative RGS approach with a novel β-probe. The method was found to be safe, feasible, and easily reproducible in daily clinical practice, with minimal radiation exposure for the staff. RGS might potentially improve radical resection rates in SI-NETs.

CLINICAL TRIALS REGISTRATION

68Ga-DOTATOC Radio-Guided Surgery with β-Probe in GEP-NET (RGS GEP-NET) [NCT0544815; https://classic.

CLINICALTRIALS

gov/ct2/show/NCT05448157 ].

[Local resection of small intestine neuroendocrine neoplasms (SI-NEN) : Current principles]

BACKGROUND

Neuroendocrine tumors of the small bowel (small intestine neuroendocrine neoplasms, SI-NEN) are the most frequent tumors of the small intestine and approximately 30-40% are still surgically treatable with curative intent at the time of diagnosis. Certain surgical principles must be followed for optimal oncological outcomes and good postoperative quality of life.

METHODS

Based on international guidelines and own experiences, the locoregional surgical treatment of SI-NENs is presented.

RESULTS

Locoregional SI-NENs should always be resected if technically feasible, as only this approach can achieve a long-term cure and even small primary tumors (< 10 mm) often already show lymphatic metastasis. The resectability of SI-NENs and their difficulty depend on the extent of lymphatic metastasis, which should be assessed based on preoperative imaging of the extent around the superior mesenteric artery. Currently, the surgical gold standard for SI-NENs is open surgery with bidigital palpation of the entire small intestine followed by primary tumor resection via small bowel segment resection, right hemicolectomy or ileocecal resection and vessel-sparing, and therefore organ-preserving lymphadenectomy (≥ 8 lymph nodes). The guidelines consider that laparoscopic or robotic approaches are justified only for early stages of SI-NENs.

CONCLUSION

Guideline-compliant surgical treatment of locoregional SI-NEN enables recurrence-free long-term survival with good quality of life.

Surgery as a Principle and Technical Consideration for Primary Tumor Resection of Small Bowel Neuroendocrine Tumors

Small bowel neuroendocrine tumors (SB-NETs) are increasingly identified and have become the most frequent entity among small bowel tumors. An increasing incidence, a high prevalence, and a prolonged survival with optimal modern multidisciplinary management makes SB-NETs a unique set of tumors to consider for surgical oncologists. The major goals of surgical treatment in the setting of SB-NET include control of tumor volume, control of endocrine secretion, and prevention of locoregional complications. Key considerations include assessment of multifocality and resection of mesenteric nodal masses with the use of mesenteric-sparing approaches and acceptance of R1 margins if necessary to clear disease while avoiding short bowel syndrome. A description through eight steps for consideration is presented to allow for systematic surgical planning and execution of resection. Moreover, some controversies and evolving considerations to the surgical principles and technical procedures remain. The role of primary tumor resection in the presence of (unresectable) liver metastasis is still unclear. Reports of feasibility of minimally invasive surgery are emerging, with undetermined selection criteria for appropriateness or long-term outcomes. Resection of SB-NETs should be considered in all patients fit for surgery and should follow principles to achieve surgical oncological control that is appropriate for the stage and tumor burden, considering the age and comorbidity of the individual patient.

The Need for Centralization for Small Intestinal Neuroendocrine Tumor Surgery: A Cohort Study from the GTE-Endocan-RENATEN Network, the CentralChirSINET Study

BACKGROUND

The concept of surgical centralization is becoming more and more accepted for specific surgical procedures.

OBJECTIVE

The aim of this study was to evaluate the relationship between procedure volume and the outcomes of surgical small intestine (SI) neuroendocrine tumor (NET) resections.

METHODS

We conducted a retrospective national study that included patients who underwent SI-NET resection between 2019 and 2021. A high-volume center (hvC) was defined as a center that performed more than five SI-NET resections per year. The quality of the surgical resections was evaluated between hvCs and low-volume centers (lvCs) by comparing the number of resected lymph nodes (LNs) as the primary endpoint.

RESULTS

A total of 157 patients underwent surgery in 33 centers: 90 patients in four hvCs and 67 patients in 29 lvCs. Laparotomy was more often performed in hvCs (85.6% vs. 59.7%; p < 0.001), as was right hemicolectomy (64.4% vs. 38.8%; p < 0.001), whereas limited ileocolic resection was performed in 18% of patients in lvCs versus none in hvCs. A bi-digital palpation of the entire SI length (95.6% vs. 34.3%, p < 0.001), a cholecystectomy (93.3% vs. 14.9%; p < 0.001), and a mesenteric mass resection (70% vs. 35.8%; p < 0.001) were more often performed in hvCs. The proportion of patients with ≥8 LNs resected was significantly higher (96.3% vs. 65.1%; p < 0.001) in hvCs compared with lvCs, as was the proportion of patients with ≥12 LNs resected (87.8% vs. 52.4%). Furthermore, the number of patients with multiple SI-NETs was higher in the hvC group compared with the lvC group (43.3% vs. 25.4%), as were the number of tumors in those patients (median of 7 vs. 2; p < 0.001).

CONCLUSIONS

Optimal SI-NET resection was significantly more often performed in hvCs. Centralization of surgical care of SI-NETs is recommended.

Surgical and Endoscopic Resection of Duodenal Neuroendocrine Tumors Have Similar Disease-Specific Survival Outcome

BACKGROUND

Duodenal neuroendocrine tumors (dNETs) are rare, and their management is not well-defined. National Comprehensive Cancer Network (NCCN) guidelines recommend surgical resection of large dNETs (> 2 cm) and endoscopic resection of small tumors (< 2 cm). We compared the survival outcomes between surgical and endoscopic resection in various dNET sizes.

METHODS

A retrospective cohort study was conducted using patient data from Surveillance, Epidemiology, and End Results Program (SEER) database. Variables analyzed included age, tumor size, grade, stage, and lymph node status. Disease-specific survival (DSS) was compared for endoscopic and surgical groups in dNET size strata: 0-0.5, 0.5-1, 1-2, 2-3, and > 3 cm. Kaplan-Meier and multivariable Cox proportional hazards models were used for survival analysis.

RESULTS

The study included 465 patients, with 124 (26.7%) undergoing surgical resection. The average age was 61.9 years, and tumor sizes ranged from 0.1 to 10.5 cm. Endoscopic resection had 40.5% of tumors between 0 and 0.5 cm, while surgery had only 21% (p < 0.001). In the surgical cohort, 79.8% had grade 1 tumors compared to 88.3% in the endoscopy group (P = 0.024). Among surgically resected cases, 48.4% (60 patients) had lymph node involvement. Age, tumor size, grade, and stage did not significantly predict survival after surgical resection. Stratified by tumor size, no difference in DSS was observed between surgery and endoscopy groups.

CONCLUSIONS

Endoscopic resection demonstrated similar survival outcomes to surgical resection across dNET sizes in this national analysis. Given the risks and the lack of survival benefits for surgery, endoscopic resection may be beneficial for both small and large tumors. Further studies are warranted to validate the current NCCN guidelines.

Optimal surgical approach for digestive neuroendocrine neoplasia primaries: Oncological benefits versus short and long-term complications

The rising incidence and the accumulating prevalence of neuroendocrine neoplasia (NEN) in the population makes this a common, prevalent and a clinically relevant disease group. Surgical resection represents the only potentially curative treatment for digestive NENs. Thus, resection should in principle be considered for all patients with NEN, although taking the patients age, relevant comorbidity, and performance status into account for operability. Patients with insulinomas, NEN of the appendix and rectal NENs are usually cured by surgery alone. However, less than a third of patients are amendable to curative surgery alone at time of diagnosis. Furthermore, recurrence is common and may occur years after primary surgery, hence the long follow-up time recommended in most NENs (>10 years). As many patients with NENs present with locoregional or metastatic disease, there is considerable debate regarding the role of debulking surgery in these settings. However, good long-term survival can be achieved in a considerable proportion of patients, with 50-70% alive up to 10 years after surgery. Location and grade are the main determinants of long-term survival. Here we present considerations to surgery for primary neuroendocrine tumors in the digestive tract.

Molecular factors, diagnosis and management of gastrointestinal tract neuroendocrine tumors: An update

The prevalence of gastrointestinal neuroendocrine tumors (GI-NETs) is increasing, and despite recent advances in their therapy, it remains inadequate in patients with advanced well-differentiated neuroendocrine tumors. These tumors present many challenges concerning the molecular basis and genomic profile, pathophysiology, clinicopathological features, histopathologic classification, diagnosis and treatment. There has been an ongoing debate on diagnostic criteria and clinical behavior, and various changes have been made over the last few years. Neuroendocrine carcinoma of the gastrointestinal system is a rare but highly malignant neoplasm that is genetically distinct from gastrointestinal system neuroendocrine tumors (NETs). The diagnosis and management have changed over the past decade. Emerging novel biomarkers and metabolic players in cancer cells are useful and promising new diagnostic tools. Progress in positron emission tomography-computerized tomography and scintigraphy with new radioactive agents (⁶⁴Cu-DOTATATE or ⁶⁸Ga-DOTATATE) replacing enough octreoscan, has improved further the current diagnostic imaging. Promising results provide targeted therapies with biological agents, new drugs, chemotherapy and immunotherapy. However, the role of surgery is important, since it is the cornerstone of management. Simultaneous resection of small bowel NETs with synchronous liver metastases is a surgical challenge. Endoscopy offers novel options not only for diagnosis but also for interventional management. The therapeutic option should be individualized based on current multidisciplinary information.