Value of somatostatin receptor scintigraphy for preoperative localization of carcinoids

Knowns and unknowns of bone metastases in patients with neuroendocrine neoplasms: A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to develop an evidence-based summary of current knowledge of bone metastases (BMs) in neuroendocrine neoplasms (NENs), inform diagnosis and treatment and standardise management between institutions.

METHODS

PubMed, Medline, EMBASE and meeting proceedings were searched for eligible studies reporting data on patients with BMs and NENs of any grade of differentiation and site; poorly-differentiated large/small cell lung cancer were excluded. Data were extracted and analysed using STATA v.12. Meta-analysis of proportions for calculation of estimated pooled prevalence of BM and calculation of weighted pooled frequency and weighted pooled mean for other variables of interest was performed .

RESULTS

A total of 149 studies met the eligibility criteria. Pooled prevalence of BMs was 18.4% (95% CI 15.4-21.5). BMs were mainly metachronous with initial diagnosis of NEN (61.2%) and predominantly osteoblastic; around 61% were multifocal, with a predisposition in axial skeleton. PET/CT seemed to provide (together with MRI) the highest sensitivity and specificity for BM detection. Almost half of patients (46.4%) reported BM-related symptoms: pain (66%) and skeletal-related events (SREs, fracture/spinal cord compression) (26.2%; weightedweighted mean time-to-SRE 9.9 months). Management of BMs was multimodal [bisphosphonates and bone-modifying agents (45.2%), external beam radiotherapy (34.9%), surgery (14.8%)] and supported by little evidence. Overall survival (OS) from the time of diagnosis of BMs was long [weighted mean 50.9 months (95% CI 40.0-61.9)]. Patients with BMs had shorter OS [48.8 months (95% CI 37.9-59.6)] compared to patients without BMs [87.4 months (95% CI 74.9-100.0); p = 0.001]. Poor performance status and BM-related symptoms were also associated with worse OS.

CONCLUSIONS

BMs in patients with NENs remain underdiagnosed and undertreated. Recommendations for management of BMs derived from current knowledge are provided. Prospective studies to inform management are required.

Appendiceal neuroendocrine neoplasms: diagnosis and management

Gastrointestinal neuroendocrine neoplasms (GI-NENs) are increasingly being recognised, while appendiceal NENs (aNENs) currently constitute the third most common GI-NEN. Appendiceal NENs are generally considered to follow an indolent course with the majority being localised at diagnosis. Thus, the initial surgical approach is not that of a planned oncological resection. Due to the localised nature of the disease in the majority of cases, subsequent biochemical and radiological assessment are not routinely recommended. Histopathological criteria (size, mesoappendiceal invasion, Ki-67 proliferation index, neuro- and angio-invasion) are mainly used to identify those patients who are also candidates for a right hemicolectomy. Goblet cell carcinoids are a distinct entity and should be treated as adenocarcinomas. Despite the absence of any substantial prospective data regarding optimal management and follow-up, recent consensus statements and guidelines have been published. The purpose of this review is to overview the published studies on the diagnosis and management of appendiceal NENs and to suggest a possible management protocol.

PET/CT using ¹⁸F-FDOPA provides improved staging of carcinoid tumor patients in a Canadian setting

AIM

In Canada, staging of carcinoid tumors is largely based on computed tomography (CT) imaging sometimes complemented with somatostatin receptor scintigraphy (SRS). This study assessed the diagnostic accuracy of 6-[¹⁸F]fluoro-3,4-dihydroxyphenylalanine (¹⁸F-FDOPA) PET/CT in neuroendocrine tumors.

METHODS

We prospectively included 27 patients with either suspected carcinoid (n=6, with all prior tests negative) or with an established diagnosis of intestinal carcinoid tumor (n=21) from two Canadian treatment centers. Findings of ¹⁸F-FDOPA PET/CT were compared with SRS, CT, and combined SRS/CT using a composite reference standard comprising all available imaging, biochemistry, surgery, and follow-up data. Sensitivity was calculated per patient, per body region, and per lesion. The contribution to patient management was estimated from the feedback of attending physicians.

RESULTS

In documented carcinoid patients, ¹⁸F-FDOPA PET/CT identified disease in 20 of 21 patients (patient-based sensitivity 95%). In 56 positive regions, ¹⁸F-FDOPA PET/CT detected 53, CT detected 34, SRS detected 34, and CT+SRS detected 39 regions, leading to region-based sensitivities of 95, 61, 62, and 71%, respectively. Lesion-based sensitivities were 96, 69, 50, and 72%, respectively. In the six patients with suspected disease only, one CT scan was positive, but ¹⁸F-FDOPA PET/CT was negative for all. ¹⁸F-FDOPA PET contributed to patient management in 12/21 patients (57%).

CONCLUSION

¹⁸F-FDOPA PET/CT proved to be an excellent modality for staging of carcinoid tumor patients, with superior performance compared with currently applied methods in Canada. In patients with suspected disease with negative prior imaging investigations, ¹⁸F-FDOPA was not helpful.

Focal myocardial uptake in a patient with carcinoid tumor by indium-111-pentetreotide on SPECT/CT

We present a case of a 44 year old man with flushing, diarrhea and markedly elevated 24 hour urinary 5-HIAA level, who was referred for an indium-111 pentetreotide study, after the excision of a carcinoid tumor in the terminal ileum. Scan findings revealed focal uptake in the myocardium and liver, suspicious for metastases. Subsequent transthoracic echocardiogram failed to demonstrate a cardiac lesion. Previously, our group has unequivocally demonstrated the usefulness of software fusion of SPECT and CT imaging in the evaluation of a carcinoid metastasizing to the myocardium. This case illustrates that hardware SPECT/CT fusion imaging utilizing indium-111 pentetreotide to evaluate metastatic carcinoid tumors can be useful. In addition, the echocardiogram can yield false negative results, because of a smaller lesion size and the influence of an operator-dependent factor.

Scintigraphic detection of carcinoid tumors with a cost effectiveness analysis

AIM: To evaluate the diagnostic sensitivity and accuracy and the cost-effectiveness of this technique in the detection of gastroenteropancreatic carcinoid tumors and their metastases in comparison with conventional imaging methods.

METHODS: Somatostatin receptor scintigraphy (SRS) was performed in 24 patients with confirmed carcinoids and 7 under investigation. The results were compared with those of conventional imaging methods (chest X-ray, upper abdominal ultrasound, chest CT, upper and lower abdominal CT). Also a cost-effectiveness analysis was performed comparing the cost in Euro of several combinations of SRS with conventional imaging modalities.

RESULTS: SRS visualized primary or metastatic sites in 71.0% of cases and 61.3% of conventional imagings. The diagnostic sensitivity of the method was higher in patients with suspected lesions (85.7% vs 57.1%). SRS was less sensitive in the detection of metastatic sites (78.9% vs 84.2%). The undetectable lesions by SRS metastatic sites were all in the liver. Between several imaging combinations, the combinations of chest X-ray/upper abdominal CT/SRS and chest CT/upper abdominal CT/SRS showed the highest sensitivity (88.75%) in terms of the number of detected lesions. The combinations of chest X-ray/upper abdominal US/SRS and chest CT/upper abdominal ultrasound/SRS yielded also a quite similar sensitivity (82%). Compared to the cost of the four sensitive combinations the combination of chest X-ray/upper abdominal ultrasound/SRS presented the lower cost, 1183.99 Euro vs 1251.75 Euro for chest CT/upper abdominal ultrasound/SRS, 1294.93 Euro for chest X/ray/upper abdominal CT/SRS and 1362.75 Euro for chest CT/upper abdominal CT/SRS.

CONCLUSION: SRS imaging is a very sensitive method for the detection of gastroenteropancreatic carcinoids but is less sensitive than ultrasound and CT in the detection of liver metastases. Between several imaging combinations, the combination of chest X-ray/upper abdominal CT/SRS shows the highest sensitivity with a cost of 1294.93 Euro.

Consensus report on the use of somatostatin analogs for the management of neuroendocrine tumors of the gastroenteropancreatic system

This consensus report gives a detailed description of the use of somatostatin analogs in the management of neuroendocrine tumors of the gastroenteropancreatic system. As background information we have outlined critical aspects of the pathology, the use of tumor markers, a definition of functional and non-functional digestive neuroendocrine tumors, different imaging modalities, surgical considerations, liver embolization and the use of cytotoxic drugs as well as interferon. Included in the report is an overview of somatostatin, somatostatin analogs and its receptor expression in different neuroendocrine tumors. It will also define the binding affinities of different somatostatin analogs to the five different subtypes of somatostatin receptor. We compare the efficacy of octreotide and lanreotide in reducing diarrhea and flushing. Side-effects are described and we provide practical information on somatostatin analog treatment.

Imaging of neuroendocrine tumors: accuracy of helical CT versus SRS

BACKGROUND

We retrospectively compared the accuracy of somatostatin receptor scintigraphy (SRS) with that of helical computed tomography (CT) in the detection and localization of primary and metastatic neuroendocrine tumors.

METHODS

A medical record search identified 27 patients with known or clinically suspected neuroendocrine tumors who underwent helical CT and SRS within 3 months of one another at our institution. CT images were evaluated retrospectively by two blinded radiologists who used consensus reading. Images were evaluated for the presence or absence of primary tumor and hepatic and extrahepatic metastases. CT results were compared with the SRS report as interpreted by the nuclear medicine physicians. The results of the surgical, clinical follow-up, and pathologic findings were considered as the gold standard. Sensitivity, specificity, and accuracy were calculated for both imaging techniques. In addition, McNemar analysis was performed to determine statistically significant differences between CT and SRS.

RESULTS

Helical CT was more sensitive than SRS in the detection of extrahepatic metastases, and the difference between the two imaging modalities was statistically significant (p = 0.0312) as determined by the McNemar chi-square test. However, the difference between CT and SRS in detecting primary neuroendocrine tumors, hepatic metastasis, and combined hepatic and extrahepatic metastasis was not statistically significant (p = 0.625, 1.000, and 1.000, respectively).

CONCLUSION

Helical CT and SRS have similar sensitivity, specificity, and accuracy in detecting primary neuroendocrine tumor and hepatic metastasis. However, helical CT appears to be more sensitive in detecting extrahepatic metastasis from primary neuroendocrine tumors.

Diagnostic uses of radiolabelled somatostatin receptor analogues in gastroenteropancreatic endocrine tumours

Numerous studies have established that gastroenteropancreatic endocrine tumours (carcinoids and pancreatic endocrine tumours) resemble a number of other tumours in overexpressing somatostatin receptors that can bind octreotide or lanreotide with high affinity (i.e. possess sst2/sst5 receptors). Recent studies report that radiolabelled somatostatin analogues can be used to image these tumours (somatostatin receptor scintigraphy) and may be useful for peptide-directed radionuclide therapy. In this paper the evidence is reviewed that has led to establishing somatostatin receptor scintigraphy as the initial imaging modality of choice in patients with gastroenteropancreatic tumours. This conclusion is based on an understanding of the results with conventional imaging modalities (ultrasound, computed tomographic scan, magnetic resonance imaging, angiography) available prior to somatostatin receptor scintigraphy and the results of studies demonstrating the sensitivity and specificity of somatostatin receptor scintigraphy. Most important in this regard are the results of studies that have assessed the use of somatostatin receptor scintigraphy on clinical management. Each of these areas is reviewed in this paper.

[Somatostatin receptor scintigraphy. When would a SPECT study be performed?]

Somatostatin receptor scintigraphy has become an essential tool in the treatment planning of patients with carcinoid tumor (CaT) and pancreatic neuroendocrine tumors (PNET). However, the contribution of SPECT images in the diagnosis and staging of these tumors has not been well established.

OBJECTIVE

1) To find out if SPECT improves the sensitivity of planar imaging and adds any value to tumor diagnosis, and 2) To determine under which circumstances SPECT images must be obtained.

MATERIAL AND METHODS

We have evaluated 49 patients, 26 females and 23 males, using both planar and SPECT 111In-DTPAOC images. The patients were classified into three groups according to their clinical indication: Group A: Indolent symptoms of CaT or PNET (n = 9); Group B: Known or functioning CaT or PNET tumors (n = 22); Group C: Post-surgical follow-up (n = 18). The total number of SPECT studies were 51 (37 abdomen, 13 thorax and 1 brain). In all cases SPECT was performed 24 hours after 111In-DTPAOC injection. Scintigraphic images were compared with surgical findings in 17 patients and with a synthesis of biochemical, clinical and CT findings in the other patients.

RESULTS

16 primary lesions were detected with planar images whereas SPECT detected 18. The two tumors detected only by SPECT were a bronchial CaT and an insulinoma located in the pancreatic tail. Planar and SPECT image sensitivities were 66.6% and 75% respectively. Twenty one patients developed metastatic disease. Sensitivities of planar and SPECT images for metastases were 76.1% and 90.4% respectively. Furthermore, SPECT helps planar images in the evaluation of six patients with uncertain images (lesions with low receptor density or with an uncertain scintigraphic localization). Therefore, in 15.6% of patients with primary or metastatic tumors, planar images were normal whereas SPECT was abnormal and SPECT provided an added value in 21.8% of the studies with abnormal planar images.

CONCLUSIONS

We recommend the use of SPECT images in: 1) Patients with specific functional clinical syndrome or with a known CaT or PNET and normal planar images. 2) When planar images are abnormal only in primary tumor. 3) In order to confirm the absence of other metastases in patients with known liver metastases. 4) In order to enhance the detection of lesions with low receptor density and uncertain planar images and 5) In order to determine exactly the anatomic location of some lesions

Evaluation of (111)In-pentetreotide, (131)I-MIBG and bone scintigraphy in the detection and clinical management of bone metastases in carcinoid disease

Bone metastases are assumed to be rare in carcinoid disease and to be associated mainly with bronchial primaries. The aim of the present study was to evaluate the occurrence of bone metastases in patients with metastatic carcinoid tumours, and the role of various nuclear medicine modalities (bone scintigraphy, (111)In-pentetreotide and (131)I-MIBG) in its detection and clinical management. Nine (2 women, 7 men, median age 65 years) out of 86 consecutive carcinoid patients treated between 1987 and 1998 developed bone metastases (10%) with a median interval of 37 months between the diagnosis of metastatic carcinoid and bone metastases. Seven of them had non-bronchial primaries. (111)In-pentetreotide scintigraphy failed to detect the bone lesions in 50% of the cases, and (131)I-meta-iodobenzylguanidine(MIBG) scintigraphy in almost 80% of cases. Standard bone scintigraphy, however, was positive in all. Pain relief of bone metastases by means of radiation therapy was obtained in 5 of 6 patients. In another patient palliation of pain symptoms was obtained with Rhenium-186-hydroxyethylidene diphosphonate. Octreotide, Interferon of MIBG were ineffective for this purpose. It is concluded that bone metastases in carcinoid patients may be missed on (131)I-MIBG and (111)In-pentetreotide scintigraphy. Bone scintigraphy is a sensitive imaging technique. Diagnostic nuclear medicine modalities may be helpful in the clinical management of carcinoid disease.

Diagnostic, surgical and medical aspect of the midgut carcinoids

This review covers the incidence, prognosis, diagnosis and treatment of midgut carcinoids with emphasis on the surgical and peri-operative aspects. Midgut carcinoids are rare neuro-endocrine tumours which become manifest once they have metastasized to the liver. Treatment of metastatic disease may include radical resection but is usually palliative. The tumour grows relatively slow. Besides the biochemical effects resulting in the carcinoid syndrome, patients may suffer from mechanical mass effects of the tumour. Medical treatment can alleviate the biochemical effects of the tumour, but has a limited effect on tumour growth. The introduction of octreotide was a milestone in palliation of these symptoms and has led to more aggressive treatment protocols. Treatment aimed at cytoreduction of hepatic metastasis and diminished secretion of bioactive amines may achieve good palliation. Cytoreduction may be performed by means of surgery, hepatic arterial ligation, (chemo)embolization, cryosurgery, radio-frequency ablation, internal radiation or even liver transplantation. The role of these options will be discussed in this review.

Octreotide for cancer of the liver and biliary tree

Inoperable liver tumors have an unfavorable natural course despite various therapeutic modalities. Octreotide, a somatostatin analog, has shown considerable antitumor activity on animal models of various hepatic tumors and on isolated cell culture lines. In this paper, a review of the experimental evidence is presented. Moreover clinical papers of case reports of uncontrolled studies of patients are also reviewed. The majority of clinical studies provide evidence of a clinical and biochemical response of liver endocrine tumors while regression of tumor size is a rare event. A randomized controlled trial of octreotide in the treatment of advanced hepatocellular carcinoma has shown a significant survival benefit in the treated patients. Literature reports indicate a stimulatory effect of octreotide on Kupffer cells as a possible antitumor mechanism, but other antiproliferative actions of octreotide have been suggested but not proved. Finally the question of the presence and affinity of somatostatin receptors on liver tumor tissue is discussed. In conclusion, according to our experience, octreotide administration is the best available treatment for advanced inoperable hepatocellular carcinoma and future better patient selection, based on receptor subtypes, might further improve the results.

Recent advances in carcinoid pathogenesis, diagnosis and management

Carcinoid tumors usually present as diagnostic dilemmas due to obscure or nonspecific symptomatology. Advances in molecular biology are allowing the investigation of molecular markers of aggressiveness, better serum tumor markers, as well as the molecular pathogenesis of carcinoid heart disease. Somatostatin receptor scintigraphy (SRS) and whole body positron emission tomography (PET) are providing much improved sensitivity in localization of both primary and metastatic tumors. Long acting depot somatostatin analogues are combining effectiveness and ease of use for medical management of carcinoid syndrome. An additional benefit may be tumor growth suppression.

Diagnosing gastrointestinal malignancies

OBJECTIVES

To provide an overview of imaging studies that can be used to help diagnose gastrointestinal malignancies and a brief description of tumor markers specific for these cancers.

DATA SOURCES

Published professional articles, textbooks, and clinical procedural manuals.

CONCLUSIONS

Diagnosing gastrointestinal malignancies can be problematic due to the relative lack of signs and symptoms, especially early in the disease process. While clinical suspicion may lead to a tentative diagnosis, imaging studies and tumor markers can provide confirmation of the suspected malignancy.

IMPLICATIONS FOR NURSING PRACTICE

An understanding of the requirements of imaging studies and tumor markers will allow for better preparation of the patient by the nurse for the test and can assist the nurse in helping the patient understand the need for and results of the diagnostic work-up.

Prospective study of somatostatin receptor scintigraphy and its effect on operative outcome in patients with Zollinger-Ellison syndrome

OBJECTIVE

To determine the relative abilities of somatostatin receptor scintigraphy (SRS) and conventional imaging studies (computed tomography, magnetic resonance imaging, ultrasound, angiography) to localize gastrinomas before surgery in patients with Zollinger-Ellison syndrome (ZES) subsequently found at surgery, and to determine the effect of SRS on the disease-free rate.

SUMMARY BACKGROUND DATA

Recent studies demonstrate that SRS is the most sensitive imaging modality for localizing neuroendocrine tumors such as gastrinomas. Because of conflicting results in small series, it is unclear in ZES whether SRS will alter the disease-free rate, which gastrinomas are not detected, what factors contribute to failure to detect a gastrinoma, or whether the SRS result should be used to determine operability in patients without hepatic metastases, as recently recommended by some investigators.

METHODS

Thirty-five consecutive patients with ZES undergoing 37 exploratory laparotomies for possible cure were prospectively studied. All had SRS and conventional imaging studies before surgery. Imaging results were determined by an independent investigator depending on surgical findings. All patients underwent an identical surgical protocol (palpation after an extensive Kocher maneuver, ultrasound during surgery, duodenal transillumination, and 3 cm duodenotomy) and postoperative assessment of disease status (fasting gastrin, secretin test imaging within 2 weeks, at 3 to 6 months, and yearly), as used in pre-SRS studies previously.

RESULTS

Gastrinomas were detected in all patients at each surgery. Seventy-four gastrinomas were found: 22 duodenal, 8 pancreatic, 3 primaries in other sites, and 41 lymph node metastases. The relative detection order on a per-patient or per-lesion basis was SRS > angiography, magnetic resonance imaging, computed tomography > ultrasound. On a per-lesion basis, SRS had greater sensitivity than all conventional studies combined. SRS missed one third of all lesions found at surgery. SRS detected 30% of gastrinomas < or =1.1 cm, 64% of those 1.1 to 2 cm, and 96% of those >2 cm and missed primarily small duodenal tumors. Tumor size correlated closely with SRS rate of detection. SRS did not increase the disease-free rate immediately after surgery or at 2 years mean follow-up.

CONCLUSIONS

SRS is the most sensitive preoperative imaging study for extrahepatic gastrinomas in patients with ZES and should replace conventional imaging studies as the preoperative study of choice. Negative results of SRS for localizing extrahepatic gastrinomas should not be used to decide operability, because a surgical procedure will detect 33% more gastrinomas than SRS. SRS does not increase the disease-free rate. In the future, more sensitive methods to detect small gastrinomas, especially in the duodenum and in periduodenal lymph nodes, or more extensive surgery will be needed to improve the postoperative disease-free rate in ZES.

Carcinoid disease: review of the literature

Carcinoid syndrome is the product of a rare but fascinating malignant neoplasm. Carcinoid syndrome was described more than 100 years ago, and recent advances in diagnostic localization, elucidation of the mechanisms of oncogenesis, treatment options, and, consequently, patient prognosis have been made. Current modalities of treatment, possible therapeutic implications of new avenues of research, and current literature on the chemotherapeutic combinations used are reviewed.