Role of Staging in Patients with Small Intestinal Neuroendocrine Tumours

Abstract

Small bowel neuroendocrine tumours are the commonest malignancy arising in the small intestine and have substantially increased in incidence in recent decades. Patients with small bowel neuroendocrine tumours commonly develop lymph node and/or distant metastases. Here, we examine the role of staging in 84 surgically treated patients with small bowel neuroendocrine tumours, comparing diagnostic information yielded from morphological, functional and endoscopic modalities. Furthermore, we correlate pre-operative staging with intra-operative findings in a sub-cohort of 20 patients. The vast majority of patients had been histologically confirmed to have low-grade (Ki-67 <2%) disease; however, lymph node and distant metastases were observed in 74 (88.1%) and 51 (60.7%) of patients at presentation, respectively. Liver metastases were evident in 48 (57.1%) patients, with solely peritoneal and bone metastases observed in 2 (2.4%) and 1 (1.2%) patients, respectively. Forty patients (47.6%) received multimodal treatment. In our sub-cohort analysis, pre-operative imaging understaged disease in 14/20 (70%) when compared with intra-operative findings. In patients with multifocal primary tumours and miliary liver metastases, no imaging modality was able to detect entire disease spread. Overall, presently available imaging modalities heavily underestimate disease stage, with meticulous intra-operative abdominal examination being superior to any imaging technology. Multimodal treatment has an important role in prolonging survival.

ENETS Consensus Guidelines for the Standards of Care in Neuroendocrine Tumours: Surgery for Small Intestinal and Pancreatic Neuroendocrine Tumours

“…The imaging assessment should specify the primary sites (30% multiple) often small in size, the lymph node stage and the presence of hepatic nodules [2,3] . Both CT and MR showed a similar rate of sensitivity in staging disease preoperatively but CT seems to be more effective in detecting anatomical details that matter from a surgical standpoint (i.e., vascular invasion, lymph node involvement) [4,5] . MR, either in T2 sequences or with diffusion-weighted sequences, could better detect hepatic nodules [6] .…”

“…Somatostatin receptor imaging modalities (somatostatin receptor scintigraphy [SRS] or positron emission tomography [PET] scanning with 68 Ga) are needed preoperatively for better staging tumours in terms of occult metastases and/or extra-abdominal disease [2] . Both morphological and functional imaging techniques usually underestimate disease stage [4,7] . Moreover, echocardiography should be routinely performed in order to rule out carcinoid heart disease before any surgical intervention.…”

MicroRNAs associated with small bowel neuroendocrine tumours and their metastases

“…However, this is not surprising since 90% of patients have G1 tumours and only 10% have G2 lesions. Furthermore, we do not resect patients with G3 tumours, as they are extremely rare and usually go for chemotherapy and not surgical treatment (Clift et al 2016). Therefore, it would be appropriate, but extremely difficult, for future studies to include a larger number of primary SBNETs in each grade.…”

“…Therefore, it would be appropriate, but extremely difficult, for future studies to include a larger number of primary SBNETs in each grade. Similarly, it would be interesting, but almost impossible, to assess miRNA profiles in those with N0 vs N1, as nearly all patients have G1 tumours and 90% are N1 (Clift et al 2016). However, it would be possible and important to assess those primary SBNETs with and without liver metastases, as well as circulating miRNAs in such patients.…”

Clinical Translation of a Click-Labeled 18F-Octreotate Radioligand for Imaging Neuroendocrine Tumors

“…Imaging is a pivotal part of the clinical workup when staging NET patients as well as aiding in treatment decisions and predicting response to therapy. Current anatomic imaging modalities, namely ultrasound, CT, MRI, and somatostatin receptor scintigraphy, fall short, with low sensitivity (82%-93%, 73%-83%, 89%-93%, and 89%, respectively) and operator dependence (ultrasound), thereby greatly underestimating the stage of disease (3,4). 68 Ga-DOTA-radiolabeled somatostatin analogs ( 68 Ga-labeled DOTATOC, DOTANOC, or DOTATATE) have been developed for use with PET; more recently, 64 Cu-DOTATATE has also been developed although the isotope has a branching ratio of 0.175 and a 12.7-h half-life.…”