Diagnostic accuracy of fluorine-18-fluorodeoxyglucose positron emission tomography in the evaluation of the primary tumor in patients with cholangiocarcinoma: a meta-analysis

Prognostic value of integrated morphofunctional imaging methods in inoperable intrahepatic cholangiocarcinoma

Introduction and aim

Intrahepatic cholangiocarcinoma (iCCA) is a disease characterized by rarity, heterogeneity, and high mortality, where surgical resection is often not possible. Nowadays, due to the recent introduction of new therapeutic options such as trans-arterial radioembolization (TARE), it is increasingly important to define the role of morphofunctional imaging methods for the prognostic stratification of patients affected by iCCA. The aim of the study was to verify the prognostic value of morphofunctional imaging methods at the baseline in patients with inoperable iCCA.

Methods

In total, 45 patients with iCCA were sent to our center between January 2016 and March 2021 for being evaluated to be treated with TARE. All of them underwent both [18F]-FDG-PET/CT and contrast-enhanced CT (ceCT) in a single procedure and were included in our study. The inclusion criteria were as follows: a diagnosis of inoperable iCCA; both [18F]-FDG-PET/CT and ceCT scans; and washout from therapy for at least 2 months before baseline [18F]-FDG-PET/CT and ceCT scans. Both clinical and laboratory data and baseline imaging data (ceCT and [18F]-FDG-PET/CT) were collected. In particular, regarding clinical and laboratory data, we collected overall survival (OS), gender, age, prior therapies, liver function indices, and tumor markers. Regarding ceCT, we collected TNM staging, lesion diameter, volume, vascularization, and presence of intravascular necrosis. Regarding [18F]-FDG-PET/CT, we collected TNM staging, Standard-Uptake-Value max (SUVmax), Metabolic-Tumor-Volume (MTV), and Total-Lesion-Glycolysis (TLG=MTV^*lesions SUVmean). Philips-Vue-PACS software was used, setting hepatic SUVmean as TLG threshold.

Results

A statistically significant correlation was found between some examined parameters at morphofunctional investigations at the baseline and OS. [18F]-FDG-PET/CT parameters statistically correlated with OS were the stage of disease greater than M0 (p = 0.037), major lesion SUVmax (p = 0.010), MTV (p ≤ 0.001), and TLG (p < 0.001). Other parameters at ceCT correlated with OS were the stage of disease greater than T2 (p = 0.038), maximum lesion diameter (p = 0.07), volume of the major lesion (p = 0.016), and total volume of lesions (p = 0. 009). Biochemical parameters correlated with OS were gamma glutamyl transferase (GGT, p = 0.014), alkaline phosphatase (ALP, p = 0.019), carcinoembryonic antigen (CEA, p = 0.004), and carbohydrate antigen 19-9 (CA 19-9, p < 0.001). From the parameters estimated by the multivariate model, we derived a four-variable score for OS combining nodal involvement and SUVmax at [18F]-FDG-PET/CT, GGT, and CA 19-9 levels.

Conclusion

Considering our data, performing integrated pre-therapy imaging is critical for the prognostic stratification of patients with iCCA.

Contemporary advances in the endoscopic management of cholangiocarcinoma: a review of accomplished milestones and prospective opportunities

INTRODUCTION

Cholangiocarcinoma, a primary malignancy of epithelial cells of the bile ducts, has been shown to have increasing incidence rates globally. Many of the current advances aim to improve the accuracy of differentiation between benign biliary strictures and cholangiocarcinoma, which include endoscopic techniques, devices, image processing, and the use of genomic sequencing in acquired specimens.

AREAS COVERED

In this review, the authors explore the historical timeline of changes leading to modern management of cholangiocarcinoma, with special emphasis on endoscopic modalities and novel therapeutic interventions. The authors also expand on the strengths and shortcomings of endoscopic diagnostics and techniques in biliary drainage and finally discuss potential areas to focus for future research and development.

EXPERT OPINION

Despite the advances in diagnosis and management of cholangiocarcinoma, there remain multiple tasks that are still awaiting to be completed. Next-generation sequencing in the diagnosis of cholangiocarcinoma needs to be further tested, validated, and easily obtainable. Other innovative diagnostic modalities, such as the use of artificial intelligence in cholangioscopy, may provide an effective complementary modality to existing techniques. A consensus on biliary drainage needs to be defined and account for longevity and patient convenience.

Intense FDG Uptake in the Common Bile Duct Post-ERCP Mimics Acute Infectious Cholangitis

In patients with obstructive pancreatitis due to choledocholithiasis, endoscopic retrograde cholangiopancreatography (ERCP) is the standard of care. ERCP-induced inflammation or infection of the common bile duct (i.e., cholangitis) is a rare complication with a high mortality rate in severe cases. We report an unusual case of incidental findings of intense FDG uptake in the common bile duct one month post-ERCP without clinical features of acute cholangitis, indicative of inflammation of CBD associated with or exaggerated by ERCP.

18F-Fluorodeoxyglucose-PET-Computerized Tomography and non-Fluorodeoxyglucose PET-Computerized Tomography in Hepatobiliary and Pancreatic Malignancies

Molecular imaging with PET-computerized tomography (PET-CT) plays an important role in oncology. There is current and evolving evidence supporting the use of fluorodeoxyglucose (FDG) and non-FDG tracers in assessment patients with hepatobiliary and pancreatic cancers in various clinical scenarios. In this chapter, we discuss the advantages and limitations of FDG and non-FDG PET-CT in the management of patients with hepatobiliary and pancreatic cancers.

Hepatic Positron Emission Tomography: Applications in Metabolism, Haemodynamics and Cancer

Evaluating in vivo the metabolic rates of the human liver has been a challenge due to its unique perfusion system. Positron emission tomography (PET) represents the current gold standard for assessing non-invasively tissue metabolic rates in vivo. Here, we review the existing literature on the assessment of hepatic metabolism, haemodynamics and cancer with PET. The tracer mainly used in metabolic studies has been [¹⁸F]2-fluoro-2-deoxy-D-glucose (¹⁸F-FDG). Its application not only enables the evaluation of hepatic glucose uptake in a variety of metabolic conditions and interventions, but based on the kinetics of ¹⁸F-FDG, endogenous glucose production can also be assessed. 14(R,S)-[¹⁸F]fluoro-6-thia-Heptadecanoic acid (¹⁸F-FTHA), ¹¹C-Palmitate and ¹¹C-Acetate have also been applied for the assessment of hepatic fatty acid uptake rates (¹⁸F-FTHA and ¹¹C-Palmitate) and blood flow and oxidation (¹¹C-Acetate). Oxygen-15 labelled water (¹⁵O-H₂O) has been used for the quantification of hepatic perfusion. ¹⁸F-FDG is also the most common tracer used for hepatic cancer diagnostics, whereas ¹¹C-Acetate has also shown some promising applications in imaging liver malignancies. The modelling approaches used to analyse PET data and also the challenges in utilizing PET in the assessment of hepatic metabolism are presented.

Impact of 18F-FDG PET/MR based tumor delineation in radiotherapy planning for cholangiocarcinoma

PURPOSE

Radiation therapy (RT) is an effective treatment for unresectable cholangiocarcinoma (CC). Accurate tumor volume delineation is critical in achieving high rates of local control while minimizing treatment-related toxicity. This study compares ¹⁸F-FDG PET/MR to MR and CT for target volume delineation for RT planning.

METHODS

We retrospectively included 22 patients with newly diagnosed unresectable primary CC who underwent ¹⁸F-FDG PET/MR for initial staging. Gross tumor volume (GTV) of the primary mass (GTV_M) and lymph nodes (GTV_LN) were contoured on CT images, MR images, and PET/MR fused images and compared among modalities. The dice similarity coefficient (DSC) was calculated to assess spatial coverage between different modalities.

RESULTS

GTV _M ^PET/MR (median: 94 ml, range 16-655 ml) was significantly greater than GTV _M ^MR (69 ml, 11-635 ml) (p = 0.0001) and GTV _M ^CT (96 ml, 4-564 ml) (p = 0.035). There was no significant difference between GTV _M ^CT and GTV _M ^MR (p = 0.078). Subgroup analysis of intrahepatic and extrahepatic tumors showed that the median GTV _M ^PET/MR was significantly greater than GTV _M ^MR in both groups (117.5 ml, 22-655 ml vs. 102.5 ml, 22-635 ml, p = 0.004 and 37 ml, 16-303 ml vs. 34 ml, 11-207 ml, p = 0.042, respectively). The GTV _LN ^PET/MR (8.5 ml, 1-27 ml) was significantly higher than GTV _LN ^CT (5 ml, 4-16 ml) (p = 0.026). GTV^PET/MR had the highest similarity to the GTV^MR, i.e., DSC^PET/MR-MR (0.82, 0.25-1.00), compared to DSC ^PET/MR-CT of 0.58 (0.22-0.87) and DSC^MR-CT of 0.58 (0.03-0.83).

CONCLUSION

¹⁸F-FDG PET/MR-based CC delineation yields greater GTVs and detected a higher number of positive lymph nodes compared to CT or MR, potentially improving RT planning by reducing the risk of geographic misses.

Progress toward improving outcomes in patients with cholangiocarcinoma

Purpose of review:

To provide an update on latest advances in treatment of cholangiocarcinoma.

Recent findings:

Incidence of cholangiocarcinoma has been increasing over the past decade. A better understanding of the genetic landscape of cholangiocarcinoma and its risk factors resulted in earlier diagnosis and treatment option expansion to targeted therapy with FGFR inhibitors, and liver transplantation for early perihilar cholangiocarcinoma and early intrahepatic cholangiocarcinoma. IDH1/2 inhibition for intrahepatic cholangiocarcinoma is an emerging targeted therapy approach. Data supports benefits of adjuvant therapy for a subset of patients undergoing surgical resection. Approaches combining different treatment modalities such as chemotherapy, surgery, radiation therapy appear promising.

Summary:

Earlier diagnosis and genetic characterization provided additional treatment options for patients with previously incurable cholangiocarcinoma. A precision medicine approach with a focus on actionable genetic alterations and combination of treatment modalities are actively being explored and will further improve outcomes in our patients with cholangiocarcinoma.

Diagnostic Approach to Suspected Perihilar Malignancy

Background

Cholangiocarcinomas are relatively rare tumors most frequently arising from the epithelium of the hilar bile ducts. The diagnosis is often made in advanced (symptomatic) stages, which accounts for the infavorable prognosis with a 5-year survival of less than 10%. Identification of perihilar cholangiocarcinoma (pCCA) is often challenging because there is no single method offering sufficient diagnostic accuracy.

Summary

Most tumors arise in patients without specific risk factors. Clinical symptoms of pCCA are nonspecific and reliable biomarkers are lacking, with carbohydrate antigen 19-9 being the most commonly used tumor marker (but with a low accuracy). Cross-sectional imaging (CT and MRI) is used to identify and map hilar strictures and determine resectability by showing vascular involvement. Endoscopic ultrasound offers additional information on locoregional tumor spread and lymph node involvement. Endoscopic retrograde cholangiography in combination with cholangioscopy gives direct access to and imaging of hilar strictures but it does not always distinguish between pCCA and benign hilar strictures. Tissue acquisition for histological diagnosis is challenging, with frequent sampling errors regardless of the method of biopsy procurement because of the cellular paucity of tumor tissue.

Key Messages

In suspected perihilar malignancy, a mosaic of clinical data has to be taken into account. Histological evaluation of (endoscopically harvested) specimens is pivotal to differential diagnosis. Several new techniques to increase diagnostic accuracy are under investigation (biomarkers and genetic testing among others).

Intrahepatic cholangiocarcinoma: pathogenesis, current staging, and radiological findings

To this date, it is a major oncological challenge to optimally diagnose, stage, and manage intrahepatic cholangiocarcinoma (ICC). Imaging can not only diagnose and stage ICC, but it can also guide management. Hence, imaging is indispensable in the management of ICC. In this article, we review the pathology, epidemiology, genetics, clinical presentation, staging, pathology, radiology, and treatment of ICC.

Comparison of magnetic resonance imaging and 18-fludeoxyglucose positron emission tomography/computed tomography in the diagnostic accuracy of staging in patients with cholangiocarcinoma: A meta-analysis

BACKGROUND

Accurate clinical staging of patients with cholangiocarcinoma (CCA) has a significant impact on treatment decisions. In this study, we aimed to compare the diagnostic value of magnetic resonance imaging (MRI) and 18-fludeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) for staging of CCA.

METHODS

We performed comprehensive systematic search in Web of Science (including MEDLINE) and Excerpta Medica Database for relevant diagnostic studies in accordance with the preferred reporting items for systematic reviews and meta-analysis statement. Based on data extracted from patient-based analysis, we calculated the pooled sensitivity and specificity with the 95% confidence intervals (CIs). In addition, the publication bias was assessed by Deek funnel plot of the asymmetry test. The potential heterogeneity was explored by threshold effect analysis and subgroup analyses.

RESULTS

Thirty-two studies with 1626 patients were included in present analysis. In T stage, the pooled sensitivity and specificity of MRI were 0.90 (95% CI 0.86-0.93), 0.84 (95% CI 0.73-0.91) respectively. The pooled sensitivity and specificity of F-FDG PET/CT were 0.91 (95% CI 0.83-0.95) and 0.85 (0.64-0.95) respectively. In N stage, the pooled sensitivity and specificity of MRI were 0.64 (95% CI 0.52-0.74) and 0.69 (95% CI 0.51-0.87) respectively. The pooled sensitivity and specificity of PET/CT were 0.52 (95% CI 0.37-0.66) and 0.92 (95% CI 0.79-0.97) respectively. In M stage, the pooled sensitivity and specificity of F-FDG PET/CT were 0.56 (95% CI, 0.42-0.69) and 0.95 (95% CI, 0.91-0.97) respectively. The Deek test revealed no significant publication bias. No threshold effect was identified. The subgroup analyses showed that pathological type (extrahepatic cholangiocarcinoma vs hilar cholangiocarcinoma/intrahepatic cholangiocarcinoma), country (Asia vs non-Asia) and type of MRI (1.5T vs. 3.0T) were potential causes for the heterogeneity of MRI studies and country (Asia vs non-Asia) was a potential source for F-FDG PET/CT studies.

CONCLUSION

The analysis suggested that both modalities provide reasonable diagnostic accuracy in T stage without significant differences between them. We recommend that both modalities be considered based on local availability and practice for the diagnosis of primary CCA tumors. In N stage, the diagnosis of lymph node metastasis (N) of CCA is still limited by MRI and F-FDG PET/CT, due to unsatisfactory diagnostic accuracy of both. Nevertheless, F-FDG PET/CT can be used to confirm lymph node metastasis while a negative result may not rule out metastasis. Furthermore, F-FDG PET/CT have a low sensitivity and a high specificity for detection of distant metastasis.

Challenging biliary strictures: pathophysiological features, differential diagnosis, diagnostic algorithms, and new clinically relevant biomarkers - part 1

It is frequently challenging to make the correct diagnosis in patients with biliary strictures. This is particularly important as errors may have disastrous consequences. Benign-appearing strictures treated with stents may later be revealed to be malignant and unnecessary surgery for benign strictures carries a high morbidity rate. In the first part of the review, the essential information that clinicians need to know about diseases responsible for biliary strictures is presented, with a focus on the most recent data. Then, the characteristics and pitfalls of the methods used to make the diagnosis are summarized. These include serum biomarkers, imaging studies, and endoscopic modalities. As tissue diagnosis is the only 100% specific tool, it is described in detail, including techniques for tissue acquisition and their yields, how to prepare samples, and what to expect from the pathologist. Tricks to increase diagnostic yields are described. Clues are then presented for the differential diagnosis between primary and secondary sclerosing cholangitis, IgG4-related sclerosing cholangitis, cholangiocarcinoma, pancreatic cancer, autoimmune pancreatitis, and less frequent diseases. Finally, algorithms that will help to achieve the correct diagnosis are proposed.

18F-fluorodeoxyglucose positron emission tomography (18FDG-PET) for patients with biliary tract cancer: Systematic review and meta-analysis

BACKGROUND & AIMS

The role of ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸FDG-PET) in the diagnosis and staging of patients with biliary tract cancers (BTCs) remains controversial, so we aimed to provide robust information on the utility of ¹⁸FDG-PET in the diagnosis and management of BTC.

METHODS

This systematic review and meta-analysis explored the diagnostic test accuracy of ¹⁸FDG-PET as a diagnostic tool for diagnosis of primary tumour, lymph node invasion, distant metastases and relapsed disease. Subgroup analysis by study quality and BTC subtype were performed. Changes in management based on ¹⁸FDG-PET and impact of maximum standardised uptake values (SUVmax) on prognosis were also assessed. A random effects model was used for meta-analyses.

RESULTS

A total of 2,125 patients were included from 47 eligible studies. The sensitivity (Se) and specificity (Sp) of ¹⁸FDG-PET for the diagnosis of primary tumour were 91.7% (95% CI 89.8-93.2) and 51.3% (95% CI 46.4-56.2), respectively, with an area under the curve (AUC) of 0.8668. For lymph node invasion, Se was 88.4% (95% CI82.6-92.8) and Sp was 69.1% (95% CI 63.8-74.1); AUC 0.8519. For distant metastases, Se was 85.4% (95% CI 79.5-90.2) and Sp was 89.7% (95% CI86.0-92.7); AUC 0.9253. For relapse, Se was 90.1% (95% CI 84.4-94.3) and Sp was 83.5% (95% CI 74.4-90.4); AUC 0.9592. No diagnostic threshold effect was identified. Meta-regression did not identify significant sources of heterogeneity. Sensitivity analysis revealed no change in results when analyses were limited to studies with low risk of bias/concern. The pooled proportion of change in management was 15% (95% CI 11-20); the majority (78%) due to disease upstaging. Baseline high SUVmax was associated with worse survival (pooled hazard ratio of 1.79; 95% CI 1.37-2.33; p <0.001).

CONCLUSIONS

There is evidence to support the incorporation of ¹⁸FDG-PET into the current standard of care for the staging (lymph node and distant metastases) and identification of relapse in patients with BTC to guide treatment selection; especially if the identification of occult sites of disease would change management, or if diagnosis of relapse remains unclear following standard of care imaging. The role for diagnosis of the primary tumour remains controversial due to low sensitivity and ¹⁸FDG-PET should not be considered as a replacement for pathological confirmation in this setting.

LAY SUMMARY

A positron emission tomography (PET scan), using ¹⁸F-fluorodeoxyglucose (¹⁸FDG), can help doctors identify areas of cancer in the body by highlighting "hot spots". These hotspots may be cancerous (true positive) but may also be non-cancerous, like inflammation (false positive). We show that PET scans are useful to assess how far advanced the cancer is (by assessing spread to lymph glands and to other organs) and also to identify if the cancer has recurred (for example after surgery), thus helping doctors to make treatment decisions. However, a biopsy is still needed for the initial diagnosis of a biliary tract cancer, because of the high chance of a "false positive" with PET scans.

Clinical presentation, diagnosis and staging of cholangiocarcinoma

Cholangiocarcinoma (CCA) is a heterogeneous group of tumours, derived from cells of the biliary tree, which represent the second most frequent primary liver tumour. According to the most recent classifications, CCA can be subdivided into intrahepatic (iCCA) and extrahepatic (eCCA) which include perihilar (pCCA) and distal (dCCA) CCA. CCA are usually identified at advanced stages, when the primary tumour grows enough to produce a large liver mass or when jaundice has developed because of biliary tree obstruction. The ongoing challenges in the identification of risk factors and definition of a specific population at higher risk of developing CCA are the main challenges for the development of screening programs. Therefore, late diagnosis remains an unresolved issue in CCA. Imaging plays an important role in the detection and characterization of CCA, helping with radiological diagnosis, guiding biopsy procedures and allowing staging of the tumour. This review focuses on clinical presentations and diagnosis and staging techniques of CCA.

Modern work-up and extended resection in perihilar cholangiocarcinoma: the AMC experience

AIM

Perihilar cholangiocarcinoma (PHC) is a challenging disease and requires aggressive surgical treatment in order to achieve curation. The assessment and work-up of patients with presumed PHC is multidisciplinary, complex and requires extensive experience. The aim of this paper is to review current aspects of diagnosis, preoperative work-up and extended resection in patients with PHC from the perspective of our own institutional experience with this complex tumor.

METHODS

We provided a review of applied modalities in the diagnosis and work-up of PHC according to current literature. All patients with presumed PHC in our center between 2000 and 2016 were identified and described. The types of resection, surgical techniques and outcomes were analyzed.

RESULTS AND CONCLUSION

Upcoming diagnostic modalities such as Spyglass and combinations of serum biomarkers and molecular markers have potential to decrease the rate of misdiagnosis of benign, inflammatory disease. Assessment of liver function with hepatobiliary scintigraphy provides better information on the future remnant liver (FRL) than volume alone. The selective use of staging laparoscopy is advisable to avoid futile laparotomies. In patients requiring extended resection, selective preoperative biliary drainage is mandatory in cholangitis and when FRL is small (< 50%). Preoperative portal vein embolization (PVE) is used when FRL volume is less than 40% and optionally includes the left portal vein branches to segment 4. Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) as alternative to PVE is not recommended in PHC. N2 positive lymph nodes preclude long-term survival. The benefit of unconditional en bloc resection of the portal vein bifurcation is uncertain. Along these lines, an aggressive surgical approach encompassing extended liver resection including segment 1, regional lymphadenectomy and conditional portal venous resection translates into favorable long-term survival.

Diagnosis and Management of Intrahepatic and Extrahepatic Cholangiocarcinoma

Cholangiocarcinomas (CC) are rare tumors which usually present late and are often difficult to diagnose and treat. CCs are categorized as intrahepatic, hilar, or extrahepatic. Epidemiologic studies suggest that the incidence of intrahepatic CCs may be increasing worldwide. In this chapter, we review the risk factors, clinical presentation, and management of cholangiocarcinoma.

Cholangiocarcinoma: Current Knowledge and New Developments

Cholangiocarcinoma (CCA) is the second most common primary malignancy. Although it is more common in Asia, its incidence in Europe and North America has significantly increased in recent decades. The prognosis of CCA is dismal. Surgery is the only potentially curative treatment, but the majority of patients present with advanced stage disease, and recurrence after resection is common. Over the last two decades, our understanding of the molecular biology of this malignancy has increased tremendously, diagnostic techniques have evolved, and novel therapeutic approaches have been established. This review discusses the changing epidemiologic trends and provides an overview of newly identified etiologic risk factors for CCA. Furthermore, the molecular pathogenesis is discussed as well as the influence of etiology and biliary location on the mutational landscape of CCA. This review provides an overview of the diagnostic evaluation of CCA and its staging systems. Finally, new therapeutic options are critically reviewed, and future therapeutic strategies discussed.

Imaging of Cholangiocarcinoma

Cholangiocarcinoma (CC) is the second most common primary hepatobiliary tumour, and it is increasing in incidence. Imaging characteristics, behaviour, and therapeutic strategies in CC differ significantly, depending on the morphology and location of the tumour. In cross-sectional imaging, CCs can be classified according to the growth pattern (mass-forming, periductal infiltrating, intraductal) and the location (intrahepatic, perihilar, extrahepatic/distal). The prognosis of CC is unfavourable and surgical resection is the only curative treatment option; thus, early diagnosis (also in recurrent disease) and accurate staging including the evaluation of lymph node involvement and vascular infiltration is crucial. However, the diagnostic evaluation of CC is challenging due to the heterogeneous nature of the tumour. Diagnostic modalities used in the imaging of CC include transabdominal ultrasound, endosonography, computed tomography, magnetic resonance imaging with cholangiopancreatography, and hybrid imaging such as positron emission tomography/computed tomography. In this review, the potential of cross-sectional imaging modalities in primary staging, treatment monitoring, and detection of recurrent disease will be discussed.

The Role of F-18 FDG PET/CT in Intrahepatic Cholangiocarcinoma

PURPOSE

The aim of this study was to evaluate the diagnostic and prognostic role of metabolic parameters of FDG PET/CT in patients with intrahepatic cholangiocarcinoma (ICC).

METHODS

From December 2008 to December 2013, 76 FDG PET/CT scans performed for initial staging of ICC in a single institution (57 male and 19 female; mean age 68 ± 9 years) were retrospectively reviewed. Patients with history of other known malignancy were excluded. Detection rates of regional lymph node and distant metastasis by FDG PET/CT were analyzed in comparison with conventional imaging modalities such as CT or MRI. Metabolic parameters including maximum, peak and mean standardized uptake values (SUVmax, SUVpeak, SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), glucose corrected SUV (SUVgluc), and glucose corrected TLG (TLGgluc) were measured for the primary tumor. Cut-off values for the metabolic parameters were calculated by ROC curve analysis, and used to dichotomize the patient groups. The overall survival time (OS) was calculated and compared using the Cox proportional hazard regression analysis.

RESULTS

The median duration of follow-up period was 5.4 months (interquartile range: 1.45∼15.45). FDG PET/CT showed higher sensitivity than conventional imaging modalities in detection of regional node involvement (74.5 % vs. 61.8 %, p = 0.013). In six patients, distant metastasis was identified only by FDG PET/CT. The mean SUVmax, SUVpeak, SUVmean, MTV, and TLG for the primary tumor were 8.2 ± 3.1, 6.8 ± 2.5, 4.0 ± 0.8, 192.7 ± 360.5 cm³, and 823.7 ± 1615.4, respectively. Patients with higher (≥7.3, HR: 4.280, p = 0.001), higher SUVpeak (≥6.5, HR: 2.333, p = 0.020), higher SUVmean (≥3.9, HR: 2.799, p = 0.004), higher SUVgluc (≥8.1, HR: 2.648, p = 0.012), and higher TLGgluc (≥431.6, HR: 2.186, p = 0.030) showed significantly shorter survival time. By multivariate study, operability was an independent prognostic factor for longer survival (HR: 4.113, p = 0.005).

CONCLUSION

FDG PET/CT is an important diagnostic imaging tool in the nodal staging and detection of distant metastasis in ICC patients. Metabolic parameters may have a significant role as prognostic factors in patients with ICC.

Tubular adenoma of the common bile duct with uptake in 18F-FDG PET: A case report

A 64-year-old man presented with epigastric discomfort and nausea. Laboratory analyses revealed increased levels of total and direct bilirubin, and increased levels of aminotransferases. Computed tomography revealed the presence of a mass in the distal common bile duct. Endoscopic retrograde cholangiopancreatography and intraductal ultrasonography revealed a 25 mm filling defect in the distal common bile duct, and biopsy of the lesion disclosed the presence of tubular adenoma. Using fluorine-18 fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) revealed an increased accumulation of the tracer in the lesion, with a maximum standard uptake value (SUV_max) of 3.3. The patient received a pylorus-preserving pancreatoduodenectomy. The histopathological examination revealed a tubular adenoma with low-grade atypia. The patient remains alive 15 months following the surgery, with no evidence of recurrence of the adenoma. ¹⁸F-FDG PET has been successfully applied in clinical practice to detect a wide variety of tumor types, including lymphoma, lung, colon and bile duct cancer. In the present study, a case of bile duct adenoma with low-grade atypia was reported, revealing the uptake of ¹⁸F-FDG. ¹⁸F-FDG PET may be able to detect premalignant tumors of the bile duct, although whether ¹⁸F-FDG PET is able to differentially discriminate between diagnoses of adenoma and carcinoma of the bile duct remains to be fully elucidated, and the assessment of further case studies is required.

Radiological Imaging for Assessing the Respectability of Hilar Cholangiocarcinoma: A Systematic Review and Meta-Analysis

Hilar cholangiocarcinoma (HCC) remains one of the most difficult tumors to stage and treat. The aim of the study was to assess the diagnostic efficiency of computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computer tomography (PET/CT) in evaluating the resectability of HCC. A systematic search was performed of the PubMed, EMBASE, and Cochrane databases. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated for individual studies and pooled data as well as test for heterogeneity and public bias. Our data showed that CT had the highest pooled sensitivity at 95% (95% CI: 91–97), whereas PET/CT had the highest pooled specificity at 81% (95% CI: 69–90). The area under the curve (AUC) of CT, MRI, and PET/CT was 0.9269, 0.9194, and 0.9218, respectively. In conclusion, CT is the most frequently used imaging modality to assess HCC resectability with a good sensitivity and specificity. MRI was generally comparable with that of CT and can be used as an alternative imaging technique. PET/CT appears to be the best technique in detecting lymph node and distant metastasis in HCC but has no clear role in helping to evaluate issues of local resectability.

Intra-arterial yttrium-90 radioembolization combined with systemic chemotherapy is a promising method for downstaging unresectable huge intrahepatic cholangiocarcinoma to surgical treatment

PURPOSE

To evaluate the downstaging efficacy of yttrium-90 radioembolization (Ytt-90)-associated with chemotherapy and the results of surgery for initially unresectable huge intrahepatic cholangiocarcinoma (ICC).

METHODS

Between January 2008 and October 2013, unresectable ICC were treated with chemotherapy and Ytt-90. Patients with unique tumors localized to noncirrhotic livers and without extrahepatic metastasis were considered to be potentially resectable and were evaluated every 2 months for possible secondary resection.

RESULTS

Forty-five patients were treated for unresectable ICCs; ten had potentially resectable tumors, and eight underwent surgery. Initial unresectability was due to the involvement of the hepatic veins or portal vein of the future liver remnant in seven and one cases, respectively. Preoperative treatment induced significant decreases in tumor volume (295 vs. 168 ml, p = 0.02) and allowed for R0 resection in all cases. Three patients (37.5 %) had Clavien-Dindo grade three or higher complications, including two postoperative deaths. The median follow-ups were 15.6 [range 4-40.7] months after medical treatment initiation and 7.2 [0.13-36.4] months after surgery. At the end of the study period, five patients were still alive, with one patient still alive 40 months after medical treatment initiation (36.4 months after surgery); two patients experienced recurrences.

CONCLUSIONS

For initially unresectable huge ICCs, chemotherapy with Ytt-90 radioembolization is an effective downstaging method that allows for secondary resectability.

(11)C-Choline and FDG PET/CT Imaging of Primary Cholangiocarcinoma: A Comparative Analysis

OBJECTIVES

This study aimed to compare the diagnostic values of (11)C-choline and (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) in patients with cholangiocarcinoma (CCA).

METHODS

This prospective study was conducted on 10 patients (6 males and 4 females), aged 42-69 years, suspected of having CCA based on CT or magnetic resonance imaging (MRI) results. (11)C-choline and (18)F-FDG PET/CT studies were performed in all patients over 1 week. PET/CT results were visually analyzed by 2 independent nuclear medicine physicians and quantitatively by calculating the tumor-to-background ratio (T/B).

RESULTS

No (11)C-choline PET/CT uptake was observed in primary extrahepatic or intrahepatic CCA cases. Intense (18)F-FDG avidity was detected in the tumors of 8 patients (%80). Two patients, who were (18)F-FDG negative, had primary extrahepatic CCA. Ki-67 measurements were positive in all patients (range; 14.2%-39.9%). The average T/B values of (11)C-choline and (18)F-FDG were 0.4±0.2 and 2.0±1.0 in all cases of primary CCA, respectively; these values were significantly lower for (11)C-choline (P<0.005). Both FDG and (11)C-choline PET/CT detected metastatic CCA foci in all 8 patients (two patients had no metastases).

CONCLUSION

As the results suggested, primary CCA lesions showed a poor avidity for (11)C-choline, whereas (18)F-FDG PET/CT was of value for the detection of most primary CCA cases. In contrast to primary lesions, metastatic CCA lesions showed (11)C-choline avidity.