Concept of reintervention with thorough lymphadenectomy after suboptimal resection of small-intestine neuroendocrine neoplasms: A multicentre preliminary study

Results of Surgical Reintervention After Suboptimal Initial Resection for Locoregional Neuroendocrine Tumors of the Small Intestine

BACKGROUND

Complete resection is the only chance for cure in small intestine neuroendocrine neoplasms (SI-NEN). Previous ENETS guidelines proposed standards for the surgery of SI-NEN, which should be followed to provide long-term disease-free survival.

AIM

To analyze the results of reintervention for locoregional SI-NEN (stages I-III) after suboptimal initial resection.

METHODS

Perioperative characteristics of all patients who underwent surgical reintervention after suboptimal initial resection (SIR) of locoregional SI-NEN were retrieved from a prospective database. Patient characteristics, initial and redo procedures, imaging before reintervention, pathological results of SIR, and after reintervention, including missed primary tumors and lymph node metastases, were retrospectively analyzed.

RESULTS

During a 15 years period, 21 of 93 (22%) patients had surgical reinterventions after SIR. In 20 of 21 (95%) cases, the initial resection was performed outside an ENETS center of excellence. Ten (48%) of those cases were emergency operations because of the bowel obstruction or bowel bleeding. Seven SIR (33%) cases were performed laparoscopically, and in another 5 (24%) cases, a complete endoscopic mucosa resection was performed. Imaging before reintervention visualized residual disease in 15 of 21 (71%) patients. Surgical reintervention included either lymphadenectomy alone (LAD, n = 3) or small bowel resection plus systematic LAD (n = 12) or right hemicolectomy/ileocecal resection with systematic LAD (n = 6), respectively. In 19 of 21 (90%) patients, a R0 resection could be achieved. One patient (5%) experienced postoperative clinically relevant complications. According to pathology, in 10 (48%) patients lymph node metastases, in 6 (29%) patients additional primary tumors, and in 5 (24%) patients, both lymph nodes metastases and primary tumors were left behind in the SIR. After mean follow-up of 52 months, 16 (76%) of 21 patients were free of disease, 4 (19%) patients were alive with disease, and 1 patient deceased of an unrelated cause.

CONCLUSION

The proposed standards to resect locoregional SI-NEN should be followed to avoid SIR, although the prognosis after adequate surgical reintervention is good.

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 ].

Management of Small Bowel Neuroendocrine Tumours: 10 Years' Experience at a Tertiary Referral Centre

BACKGROUND

Neuroendocrine tumours (NET) arising from the small bowel are clinically challenging and are often diagnosed at advanced stages. Disease control with surgery alone can be demanding. Multimodal treatment concepts integrating surgery and non-surgical modalities could be of benefit.

METHOD

Retrospective review of consecutive adult patients with SB NET treated at Imperial College Healthcare NHS Trust between 1 January 2010 and 31 December 2019. Data regarding clinicopathological characteristics, treatments, and disease trajectory were extracted and summarised. Overall and progression/recurrence-free survival were estimated at 5 and 10 years.

RESULTS

154 patients were identified, with a median age of 64 years (range 33-87); 135/154 (87.7%) had stage III/IV disease at diagnosis. Surgery was used in 125 individuals (81.2%), typically with either segmental small bowel resection (60.8%) or right hemicolectomy (33.6%) and mesenteric lymphadenectomy for the primary tumour. Systemic and/or liver-directed therapies were used in 126 (81.8%); 60 (47.6%) had more than one line of non-surgical treatment. Median follow-up was 67.2 months (range 3.1-310.4); overall survival at 5 and 10 years was 91.0% (95% CI: 84.9-94.7%) and 82.5% (95% CI: 72.9-88.9%), respectively. Imaging-based median progression-free survival was 42.7 months (95% CI: 24.7 to 72.4); 5-year progression-free survival was 63.4% (95% CI: 55.0-70.6%); 10-year progression-free survival was 18.7% (95% CI: 12.4-26.1). Nineteen patients (12.3%) reached 10 years follow-up without disease recurrence and therefore were considered cured.

CONCLUSIONS

Most patients with SB NET present in a metastasised stage. Multimodal treatment concepts may be associated with excellent clinical outcomes. Future work should explore optimal approaches to treatment sequencing and patient selection.