Improvements in small bowel carcinoid diagnosis and staging: 18F-DOPA PET, capsule endoscopy and double balloon enteroscopy

Double-Balloon Enteroscopy in Detecting Small-Bowel Neuroendocrine Neoplasms: A Single-Center Prospective Study

BACKGROUND AND AIM

Small-bowel neuroendocrine neoplasm (sbNEN) diagnosis has improved with double-balloon enteroscopy (DBE). DBE efficacy in the detection of sbNENs is unknown. We aimed to report the experience at a single referral center for NENs.

METHODS

All consecutive patients with a suspected sbNEN selected for diagnostic DBE were enrolled.

RESULTS

Between 2011 and 2016, 25 patients were referred for a suspected sbNEN. In 15/25 patients, a primary NEN was detected outside the small bowel; in 4, NEN was excluded. After extensive workup, 6 patients (4 males, median age 50 years) underwent DBE (3 anterograde, 2 retrograde, and 1 both; median time: 60 min; median insertion 200 cm). DBE was positive in 3 patients: one had an ileal 2-cm NEN G1, one had an ileal 1.3-cm NEN G1, and one had an ileal 1-cm NEN G2, all surgically removed. Of the 3 other patients, one had a metastatic NEN of unknown primary, the other two had small intestinal NENs, both surgically removed (1.6-cm G1 and G2 NEN). DBE showed a sensitivity of 60% and, in absence of false-positive results, a specificity of 100%. Accuracy resulted 67%. No complications were observed.

CONCLUSIONS

In line with data from the literature, the present series showed that DBE is a safe and effective procedure in the diagnosis of sbNENs. Further studies are needed to better clarify the diagnostic role of DBE in the neuroendocrine tumor setting and its relationship with other techniques.

Evolving role of the endoscopist in management of gastrointestinal neuroendocrine tumors

Neuroendocrine tumors (NETs) are uncommon gastrointestinal neoplasms but have been increasingly recognized over the past few decades. Luminal NETs originate from the submucosa of the gastrointestinal tract and careful endoscopic exam is a key for accurate diagnosis. Despite their reputation as indolent tumors with a good prognosis, some NETs may have aggressive features with associated poor long-term survival. Management of NETs requires full understanding of tumor size, depth of invasion, local lymphadenopathy status, and location within the gastrointestinal tract. Staging with endoscopic ultrasound or cross-sectional imaging is important for determining whether endoscopic treatment is feasible. In general, small superficial NETs can be managed by endoscopic mucosal resection and endoscopic submucosal dissection (ESD). In contrast, NETs larger than 2 cm are almost universally treated with surgical resection with lymphadenectomy. For those tumors between 11-20 mm in size, careful evaluation can identify which NETs may be managed with endoscopic resection. The increasing adoption of ESD may improve the results of endoscopic resection for luminal NETs. However, enthusiasm for endoscopic resection must be tempered with respect for the more definitive curative results afforded by surgical treatment with more advanced lesions.

Endoscopic techniques to detect small-bowel neuroendocrine tumors: A literature review

BACKGROUND

The diagnosis of small-bowel neuroendocrine tumors (SbNETs) has improved with the advent of video capsule endoscopy (CE) and double-balloon enteroscopy (DBE). The data describing the efficacy of CE/DBE in the detection of SbNETs are scanty.

AIM

The aim of this article is to review the current evidence on the role of DBE and CE in the diagnosis of SbNETs.

MATERIAL AND METHODS

A bibliographical search was performed in PubMed using the following keywords: "neuroendocrine tumors and enteroscopy/and capsule endoscopy" and "small bowel neuroendocrine tumors."

RESULTS

CE and DBE can be complementary and show a similar diagnostic yield. The number of false-negative results has not been established yet because of the "work-up bias" observed in the majority of the studies.

CONCLUSIONS

DBE and CE appear to be both safe and effective procedures useful in the diagnosis of SbNETs. Further studies are required to clarify their potential complications and relationship with other techniques, particularly nuclear imaging.

Role of Staging in Patients with Small Intestinal Neuroendocrine Tumours

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.

Capsule endoscopy to detect primary tumour site in metastatic neuroendocrine tumours

BACKGROUND

In patients with metastatic neuroendocrine tumours, primary tumour localisation is often difficult with morphological and/or functional imaging. Although utilised in investigating various small bowel pathologies, evidence for using video capsule endoscopy to identify suspected small bowel primaries in patients exhibiting metastatic neuroendocrine tumours is limited.

AIMS

To assess the role of video capsule endoscopy in locating primary small bowel neuroendocrine tumours when conventional imaging fails to identify the origin of metastatic disease.

METHODS

We retrospectively compared our institutional database of patients presenting with metastatic neuroendocrine tumours between January 2010 and December 2013 with an analogous database of patients undergoing video capsule endoscopy for various indications. Patients whose primary tumours were not located radiologically and also underwent capsule endoscopy were identified.

RESULTS

390 patients with metastasised neuroendocrine tumours presented within the study period. In 11 (2.8%) the primary tumour was not located radiologically. Video capsule endoscopy identified lesions suggestive of small bowel primary in 8/10 patients in whom it was successful. Small bowel primary was confirmed by histological analysis of surgical specimens.

CONCLUSIONS

Our study supports the use of video capsule endoscopy as part of the diagnostic work-up in selected patients presenting with metastatic neuroendocrine tumours of unknown primary. The clinical utility of this technology requires clearer definition.

Long term survival analysis of hepatectomy for neuroendocrine tumour liver metastases

Background. Liver is the commonest site for metastasis in patients with neuroendocrine tumour (NET). A vast majority of treatment strategies including liver directed nonsurgical therapy, liver directed surgical therapy, and nonliver directed therapy have been proposed. In this study we aim to investigate the outcome of liver resection in neuroendocrine tumour liver metastases (NELM). Method. 293 patients had hepatectomy for liver metastasis in our hospital between June 1996 and December 2010. Twelve patients were diagnosed to have NET in their final pathology and their data were reviewed. Results. The median ages of the patients were 48.5 years (range 20–71 years). Eight of the patients received major hepatectomy. Four patients received minor hepatectomy. The median operation time was 418 minutes (range 195–660 minutes). The median tumor size was 8.75 cm (range 0.9–21 cm). There was no hospital mortality. The overall one-year and three-year survivals were 91.7% and 55.6%. The one-year and three-year disease-free survivals were 33.3% and 16.7%. Conclusion. Hepatectomy is an effective and safe treatment for NELM. Reasonable outcome on long term overall survival and disease-free survival can be achieved in this group of patients with a low morbidity rate.

Small bowel carcinoid: Location isn’t everything!

AIM: To investigate the prognostic significance of the primary site of disease for small bowel carcinoid (SBC) using a population-based analysis.

METHODS: The Surveillance, Epidemiology and End Results (SEER) database was queried for histologically confirmed SBC between the years 1988 and 2009. Overall survival (OS) and disease-specific survival (DSS) were analyzed using the Kaplan-Meier method and compared using Log rank testing. Log rank and multivariate Cox regression analyses were used to identify predictors of survival using age, year of diagnosis, race, gender, tumor histology/size/location, tumor-node-metastasis stage, number of lymph nodes (LNs) examined and percent of LNs with metastases.

RESULTS: Of the 3763 patients, 51.2% were male with a mean age of 62.13 years. Median follow-up was 50 mo. The 10-year OS and DSS for duodenal primaries were significantly better when compared to jejunal and ileal primaries (P = 0.02 and < 0.0001, respectively). On multivariate Cox regression analysis, after adjusting for multiple factors, primary site location was not a significant predictor of survival (P = 0.752 for OS and P = 0.966 DSS) while age, number of primaries, number of LNs examined, T-stage and M-stage were independent predictors of survival.

CONCLUSION: This 21-year, population-based study of SBC challenges the concept that location of the primary lesion alone is a significant predictor of survival.

Double-balloon enteroscopy for diagnosis of Meckel's diverticulum: comparison with operative findings and capsule endoscopy

BACKGROUND

Meckel's diverticulum (MD) is one of the most common congenital gastrointestinal malformations. It is difficult to make a preoperative diagnosis of MD. To date, few data are available describing the diagnosis of MD by double-balloon enteroscopy (DBE) and capsule endoscopy (CE).

METHODS

To assess the value of DBE in the diagnosis of MD and comparatively evaluate the diagnostic yield of DBE and CE for MD. A single-center study was performed on patients with a confirmed diagnosis of MD by surgery and postoperative pathology between January 2003 and December 2011.

RESULTS

Seventy-four patients (60 males) with a mean age of 29.0 ± 14.3 years were analyzed; 33 (55.0%) were between 21 and 40 years of age. Gastrointestinal bleeding was the major finding in 86.5% of the patients who were referred for DBE or CE examination. The mean duration of symptoms was 32.3 ± 48.7 months. In the 74 patients, the diagnostic yield of DBE for MD before surgery was 86.5% (64/74), and correct diagnoses were made in the majority of cases by retrograde DBE, with a few cases by antegrade DBE. In the 26 patients undergoing CE before DBE, the overall diagnostic yield of DBE was 84.6%, significantly greater than that of CE (7.7%, P < .000, McNemar's χ(2) test). Poor agreement was found between the 2 modalities (kappa = 0.03).

CONCLUSION

For patients who are highly suspected of having MD, DBE provides a safe, effective, and reliable means of diagnosis before surgery.

Utility of positron emission tomography/CT in the evaluation of small bowel pathology

We describe the management principles and different roles of positron emission tomography (PET)/CT in the evaluation of patients with small bowel tumours (adenocarcinoma, gastrointestinal stromal tumour, lymphoma, metastases) from initial staging, monitoring response to treatment, to detection of recurrent disease. We also discuss the various non-malignant aetiologies of small bowel fludeoxyglucose (FDG) PET uptake, and other pitfalls in FDG PET/CT interpretation. Awareness of the imaging appearances of small bowel tumours, patterns of disease spread and potential PET/CT interpretation pitfalls are of paramount importance to optimise diagnostic accuracy.

Current status of device-assisted enteroscopy: Technical matters, indication, limits and complications

Enteroscopy, defined as direct visualization of the small bowel with the use of a fiberoptic or capsule endoscopy, has progressed considerably over the past several years. The need for endoscopic access to improve diagnosis and treatment of small bowel disease has led to the development of novel technologies one of which is non-invasive, the video capsule, and a type of invasive technique, the device-assisted enteroscopy. In particular, the device-assisted enteroscopy consists then of three different types of instruments all able to allow, in skilled hands, to display partially or throughout its extension (if necessary) the small intestine. Newer devices, double balloon, single balloon and spiral endoscopy, are just entering clinical use. The aim of this article is to review recent advances in small bowel enteroscopy, focusing on indications, modifications to improve imaging and techniques, pitfalls, and clinical applications of the new instruments. With new technologies, the trials and tribulations of learning new endoscopic skills and determining their role in the diagnosis and treatment of small bowel disease come. Identification of small bowel lesions has dramatically improved. Studies are underway to determine the best strategy to apply new enteroscopy technologies for the diagnosis and management of small bowel disease, particularly obscure bleeding. Vascular malformations such as angiectasis and small bowel neoplasms as adenocarcinoma or gastrointestinal stromal tumors. Complete enteroscopy of the small bowel is now possible. However, because of the length of the small bowel, endoscopic examination and therapeutic maneuvers require significant skill, radiological assistance, the use of deep sedation with the assistance of the anesthetist. Prospective randomized studies are needed to guide diagnostic testing and therapy with these new endoscopic techniques.

The role of endoscopic imaging of the small bowel in clinical practice

Enteroscopy, defined as direct visualization of the small bowel (SB) with the use of a fiberoptic or wireless endoscope, has progressed considerably over the past several years. Technological advancements in the field have facilitated endoscopic evaluation of the SB. This comprehensive clinical review summarizes the latest modalities available to aid gastroenterologists in exploring the SB for evaluation of obscure gastrointestinal bleeding, tumors, inflammatory bowel disease, and celiac disease. Previous physical limitations in equipment that made a complete evaluation of the SB difficult have all but disappeared with the advent of capsule endoscopy, balloon-assisted enteroscopy, and spiral enteroscopy.