GI carcinoid tumours: appearance of the primary and detecting metastases

Epidemiology of Large Bowel Carcinoid Tumors in the USA: A Population-Based National Study

BACKGROUND AND AIMS

Prior studies have shown that about 90% of all carcinoid tumors occur in the GI tract. However, epidemiological studies of these tumors have been limited by small sample size. Our aim was to obtain a more robust epidemiologic survey of large bowel carcinoids (LBC), using population-based data in order to more accurately identify risk factors for these tumors.

METHODS

We used a commercial database (Explorys Inc, Cleveland, OH) which includes electronic health record data from 26 major integrated US healthcare systems. We identified all patients aged 18 and older who were diagnosed with LBC, excluding appendiceal carcinoids, between 1999 and 2018 based on Systematized Nomenclature Of Medicine-Clinical Terms (SNOMED-CT) and evaluated the prevalence of LBC. We also performed univariate analysis to describe age-, race-, and gender-based distributions and to identify potential risk factors.

RESULTS

Of the 62,817,650 individuals in the database, 4530 were identified to have LBC with an overall prevalence of 7.21/100,000. Individuals with LBC were more likely to be elderly (age > 65) [OR 2.17, CI 2.05-2.31, p < 0.0001], smokers [OR 3.25; 95% CI 3.00-3.53, p < 0.0001], have a history of alcohol use [OR 3.75; 95% CI 3.52-3.99, p < 0.0001], diabetes mellitus (DM) [OR 4.42; 95% CI 4.14-4.72, p < 0.0001], obesity [OR 1.58; 95% CI 1.43-1.74, p < 0.0001], family history of cancer [OR 8.06; 95% CI 7.47-8.71, p < 0.0001], and personal history of ulcerative colitis [OR 6.93; 95% CI 5.55-8.64, p < 0.0001] or Crohn's disease [OR 6.45; 95% CI 5.24-7.95, p < 0.0001]. The prevalence of LBC was less among Caucasians compared to African-Americans [OR 0.57; 95% CI 0.53-0.61, p < 0.0001]. There was no statistically significant gender-based difference; men versus women [OR 1.02; 95% CI 0.96-1.08, p = 0.47]. The most common presenting symptoms included flushing, diarrhea, nausea, weight loss, and abdominal pain, while the most common GI associations included perforation, obstruction, hemorrhage, intussusception, and volvulus.

CONCLUSION

This is the largest epidemiological study evaluating the prevalence of LBC. We estimated the prevalence rate of LBC to be 7.21/100,000. The presence of significant risk factors with the clinical picture suspicious for a LBC should warrant thorough evaluation as these tumors can lead to life-threatening complications. Further studies are needed to better understand the mechanism of association between these risk factors and LBC.

Vitamin D and vitamin B12 deficiencies in patients with small intestinal carcinoid tumour: is opioid use disorder a confounding factor in the diagnosis?

Carcinoid tumours have the ability to secrete various peptides and bioamines that lead to carcinoid syndrome manifested as cutaneous flushing, diarrhoea, bronchial constriction and cardiac involvement. The deficiencies of vitamins D and B₁₂ have previously been reported in patients with carcinoid tumours presumably due to chronic diarrhoea associated with the carcinoid syndrome. Herein, we chronicle the case of a patient with opioid use disorder who presented with small bowel obstruction that was found to be caused by a midgut carcinoid tumour. Laboratory studies revealed deficiencies of vitamins D and B₁₂ even though he denied diarrhoea and had no other aetiology of deficiencies of these vitamins. Additionally, this paper presents a review of the published medical literature pertaining to clinical features, diagnostic investigations and treatment of intestinal carcinoid tumours and explores possible explanations for the observed deficiencies in these patients.

Development of a novel index to discriminate bulge from mass on small-bowel capsule endoscopy

BACKGROUND

Submucosal malignant masses (SMMs) and innocent bulges look similar on small-bowel capsule endoscopy (SBCE). In a previous observational study, 4 criteria associated with innocent bulges were recognized.

OBJECTIVE

To devise and validate an index based on these criteria (smooth, protruding lesion index on capsule endoscopy [SPICE]) to discriminate SMMs from innocent bulges.

DESIGN

Single-center, prospective study.

SETTING

General hospital in Busto Arsizio, Italy.

PATIENTS

This study involved 25 of 424 consecutive SBCEs performed on as many patients having SBCE findings of smooth, round, protruding lesions.

INTERVENTION

Patients' evaluation up to the final diagnosis. At study entry, a short video clip of the lesion was obtained and deidentified for blind SPICE calculation.

MAIN OUTCOME MEASUREMENTS

SPICE accuracy, using the final diagnosis of each patient as the criterion standard.

RESULTS

Six patients had SMMs (4 GI stromal tumors, 2 neuroendocrine tumors), and 19 had innocent bulges. SPICE scores ranged from 0 to 4; they discriminated SMMs from innocent bulges (P = .002). A SPICE value >2 had 83.3% sensitivity and 89.4% specificity, and the area under the curve was 0.90 (95% confidence interval, 0.72-0.98; P < .001) for the detection of SMMs.

LIMITATIONS

Single-center study; small sample size; no invasive ascertainment in 36% of patients.

CONCLUSION

SPICE is easy to calculate and useful for distinguishing SMMs from innocent bulges. An index >2 is predictive of SMM.

Imaging of malignant neoplasms of the mesenteric small bowel: new trends and perspectives

This article describes the recent advances in radiological imaging of malignant neoplasms of the mesenteric small bowel and provides an outline of new trends and perspectives that can be anticipated. The introduction of multidetector row technology, which allows the acquisition of submillimeter and isotropic voxels, has dramatically improved the capabilities of computed tomography in the investigation of the mesenteric small bowel. This technology combined with optimal filling of small bowel loops through the use of appropriate enteral contrast agents has markedly changed small bowel imaging. Computed tomography-enteroclysis, which is based on direct infusion of enteral contrast agent into the mesenteric small bowel through a naso-jejunal tube, provides optimal luminal distension. By contrast, computed tomography-enterography is based on oral administration of enteral contrast agent. These two techniques are now well-established ones for the detection and the characterization of small bowel neoplasms. During the same time, combining the advantages of unsurpassed soft tissue contrast and lack of ionizing radiation, magnetic resonance imaging has gained wide acceptance for the evaluation of patients with suspected small bowel neoplasms. Rapid magnetic resonance imaging sequences used in combination with specific enteral contrast agents generate superb images of the mesenteric small bowel so that magnetic resonance-enteroclysis and magnetic resonance-enterography are now considered as effective diagnostic tools for both the detection and the characterization of neoplasms of the mesenteric small bowel. Recent improvements in image post-processing capabilities help obtain realistic three-dimensional representations of tumors and virtual enteroscopic views of the small bowel that are useful for the surgeon and the gastroenteroenteologist to plan surgical or endoscopic interventions. Along with a better knowledge of the potential and limitations of wireless capsule endoscopy and new endoscopic techniques, these recent developments in radiological imaging reasonably suggest that substantial changes in the investigation of small bowel tumors may be anticipated in a near future, thus potentially create a new paradigm shift after standard small bowel follow-through study has been universally abandoned.

Imaging in covert ectopic ACTH secretion: a CT pictorial review

The syndrome of ectopic adrenocorticotrophin secretion (EAS) is rare and is due to excess adrenocorticotrophin (ACTH) production from a nonpituitary tumour. These tumours can be covert, where the tumours are not readily apparent, and very small making them challenging to image. It is clinically and biochemically difficult to distinguish between covert EAS and Cushing's disease. The first-line investigation in locating the source of ACTH production is computed tomography (CT). The aim of this pictorial review is to illustrate the likely covert sites and related imaging findings. We review the CT appearances of tumours resulting in covert EAS and the associated literature. The most common tumours were bronchial carcinoid tumours, which appear as small, well-defined, round or ovoid pulmonary lesions. Rarer causes included thymic carcinoids, gastrointestinal carcinoids and pancreatic neuroendocrine tumours. Awareness of the imaging characteristics will aid identification of the source of ACTH production and allow potentially curative surgical resection.

Appendectomy or right hemicolectomy in the treatment of appendiceal carcinoid tumors?

AIMS AND BACKGROUND

Carcinoids of the appendix continue to be of interest, despite their low incidence. There is still considerable controversy surrounding these tumors, especially with regard to the role of right hemicolectomy in the surgical management. The aim of this work was to explicate the current therapeutic knowledge and to review the criteria for the indications of appendectomy or hemicolectomy.

METHODS

The records of patients who underwent appendectomies from 1990 to 2000 were analyzed. Seven patients were included in the study. The clinical data were reviewed for demographic details, tumor size, localization in the appendix, histological patterns and surgical procedures. All patients underwent appendectomy including removal of the mesenteriolum, and in one of them a right hemicolectomy was performed 3 weeks later. The mean follow-up was 7 years (range, 4-14). Follow-up data included symptoms, urinary 5-hydroxyindoleacetic acid, ultrasound examination, computerized tomography, and octreotide scanning.

RESULTS

Seven patients (0.9% of all appendectomies) were reported to have carcinoid tumors of the appendix. They were 3 men and 4 women with a mean age of 29 years. All patients were admitted for appendicitis. None suffered from the carcinoid syndrome. The site of the tumor was the apex of the appendix in 4 cases, the body in 2 cases and the base in 1 case. Mean tumor diameter was 8 mm (range, 5-29 mm); in 6 patients it was <2 cm. Treatment was appendectomy in all cases; additional right hemicolectomy was necessary in one case because of a tumor of more than 2 cm with invasion of the mesoappendix and lymph nodes. The 7-year survival rate is 100%. Six patients are without disease, while 1 patient (the one who underwent a right hemicolectomy) developed metastases in the liver 6 years after the operation. This patient, who was treated with a liver resection, is still alive.

CONCLUSIONS

According to current guidelines, an appendectomy may be performed for small carcinoid tumors (<1 cm). Reasons for more extensive surgery than appendectomy are tumor size >2 cm, lymphatic invasion, lymph node involvement, spread to the mesoappendix, tumor-positive resection margins, and cellular pleomorphism with a high mitotic index. The criteria that direct us towards major (hemicolectomy) or minor surgery (appendectomy) are controversial. Tumor size is still considered the most important prognostic factor, with a presumed increase in the risk of metastasis for tumors greater than 2.0 cm. The accepted treatment of such tumors is a right hemicolectomy. However, there is no evidence demonstrating a survival benefit for right hemicolectomy over simple appendectomy in patients with carcinoids greater than 2.0 cm in diameter.

CT Enteroclysis

Computed tomographic (CT) enteroclysis is a hybrid technique that combines the methods of fluoroscopic intubation-infusion small-bowel examinations with that of abdominal CT. The use of multidetector CT technology has made this a versatile examination that has evolved into two distinct technical modifications. CT enteroclysis can be performed by using positive enteral contrast material without intravenous contrast material and neutral enteral contrast material with intravenous contrast material. CT enteroclysis has been shown to be superior to other imaging tests such as peroral small-bowel examinations, conventional CT, and barium enteroclysis, except in the demonstration of early apthous ulcers of Crohn disease. CT enteroclysis is complementary to capsule endoscopy in the elective investigation of small-bowel disease, with a specific role in the investigation of Crohn disease, small-bowel obstruction, and unexplained gastrointestinal bleeding.

Role of 18F-dopa PET/CT imaging in the management of patients with 111In-pentetreotide negative GEP tumours

PURPOSE

To assess whether 18F-dopa PET/CT is able to provide information relevant in changing the clinical management of patients with gastro-enteropancreatic (GEP) tumours where there is negative or inconclusive conventional radiological imaging (ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI)) and 111In-pentetreotide scintigraphy.

MATERIALS AND METHODS

From January 2005 to October 2006, 84 patients with clinical and biochemical suspicion of GEP tumours were investigated by US and CT scans, MRI and 111In-pentetreotide scintigraphy. In 13/84 (15.4%) both conventional radiological imaging and 111In-pentetreotide scintigraphy provided negative or inconclusive findings, and patients were referred for 18F-dopa PET/CT imaging. Each patient received 5.3 MBq x kg(-1) 18F-dopa intravenously, and imaged 60 min later using a hybrid PET/CT scanner.

RESULTS

18F-dopa PET/CT detected the primary tumour in all 13 patients (size range, 7-26 mm, mean, 18 mm; SUVmax range, 2.3-16.3, mean, 5.7) and further 12 unsuspected lesions (size range, 12-23 mm, mean 17; SUVmax range 2.8-12.7, mean 4.6). Confirmation of the PET/CT findings was obtained in all patients from histopathological analysis of tissue obtained after surgery and/or biopsy. All the 18F-dopa-positive primary lesions were confirmed as being the primary tumour at histology, whereas of the other 12 unsuspected 18F-dopa-positive lesions, 11 were found to be metastatic deposits and one due to unspecific inflammation (one false positive result). Notably, the results of 18F-dopa PET/CT imaging changed the clinical management in 11/13 patients (84%).

CONCLUSIONS

Our preliminary results suggest that 18F-dopa PET/CT has a promising role in GEP patients with negative or inconclusive findings at conventional radiological imaging and 111In-pentetreotide scintigraphy. The findings were helpful in biopsy guidance and played a major role in changing the management of those patients.

Anatomic and functional imaging of metastatic carcinoid tumors

Carcinoid tumors are a fascinating group of neuroendocrine neoplasms that develop either sporadically or as part of an inheritable syndrome. Many tumors arise in the bronchopulmonary or gastrointestinal tract, but a neuroendocrine tumor can arise in almost any organ. The tumors have varied malignant potential depending on the site of their origin, and the clinical manifestations often are nonspecific. Metastases may be present at the time of diagnosis, which often occurs at a late stage of the disease. Imaging plays a pivotal role in the localization and staging of neuroendocrine tumors and in monitoring the treatment response. Imaging is often challenging, and a combination of anatomic and functional techniques is usually required, depending on the tumor type and location. Techniques include ultrasonography, barium studies, endoscopy, computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, iobenguane scintigraphy, and, in select cases, positron emission tomography. Coregistration of structural and functional images is often of incremental value for accurate localization of the primary tumor and any meta-static disease. Radiologists must understand the contribution of each imaging modality in the assessment of different neuroendocrine tumors. In addition, knowledge of the optimal technique for each radiologic and radionuclide imaging examination is essential. Familiarity with the protean imaging appearances of both primary and metastatic disease is essential for accurate staging, treatment monitoring, and surveillance. Finally, an understanding of the wide variety of treatment options for patients with carcinoid tumors is vital for optimal management.

Operative resection of primary carcinoid neoplasms in patients with liver metastases yields significantly better survival

BACKGROUND

It is unclear whether there is a benefit to resection of primary gastrointestinal carcinoid neoplasm with hepatic metastases. We investigated whether primary tumor resection in this setting led to a significant difference in outcomes.

METHODS

A retrospective review of patients with abdominal carcinoid neoplasms between 1995 and 2006 was performed. Data collected on patients with proven carcinoid liver metastases at initial diagnosis included whether the primary neoplasm was resected, time to progression of liver metastases, and status at last follow-up. Progression-free survival and survival were calculated by the method of Kaplan-Meier and compared by the log-rank test.

RESULTS

There were 84 patients, 60 of whom had their primary neoplasm resected. The resected group had a greater median progression-free survival of 56 months, compared with 25 months for the primary nonresected group (P < .001). Median survival time for the resected group was longer at 159 months, compared with 47 months for the nonresected group (P < .001).

CONCLUSIONS

Resection of the primary neoplasm is associated with better progression-free survival and overall survival in patients with abdominal carcinoid neoplasms. Therefore, localization and resection of the primary neoplasm should be considered, even among patients in whom the primary neoplasm is asymptomatic.

Large bowel carcinoid tumors

PURPOSE OF REVIEW

Gastrointestinal carcinoids comprise 90% of all carcinoid tumors and all carcinoids have malignant potential. This review focuses on the morphology, prognosis, detection and treatment for appendiceal, colonic and rectal carcinoids.

RECENT FINDINGS

Computed tomography exists as an initial examination for the primary carcinoid tumor as well as for metastases. There have, however, been recent developments of newer and more accurate modalities. Octreotide scanning has a sensitivity of primary tumor detection of 90%; additionally, I- or I-meta-iodobenzylguanidine scanning and tracer-specific positron emission tomographic scans have demonstrated encouraging results. Further advancements in treatment with tumor-targeted therapy and biochemical evaluation of carcinoids have shown promise.

SUMMARY

The recent progress with scintigraphic and radiologic modalities has provided better means for diagnosis of primary and metastatic carcinoid tumors. These newly discovered diagnostic modalities have been more encouraging than the recent treatment approaches that have been studied with regard to metastatic carcinoids. While surgery remains the mainstay of treatment of nonmetastatic carcinoid, there have been studies for various medical treatments of metastatic disease. Unfortunately, there have been disappointing results with regard to improvement of tumor response and patient survival, but a foundation has been established for future trials employing alternative agents and exploration of combination therapies.