Diagnostic performance of Fluorine-18-Fluorodeoxyglucose positron emission tomography in the assessment of pleural abnormalities in cancer patients: A systematic review and a meta-analysis

Personalised PET imaging in oncology: an umbrella review of meta-analyses to guide the appropriate radiopharmaceutical choice and indication

PURPOSE

For several years, oncological positron emission tomography (PET) has developed beyond 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG). This umbrella review of meta-analyses aims to provide up-to-date, comprehensive, high-level evidence to support appropriate referral for a specific radiopharmaceutical PET/computed tomography (CT) or PET/magnetic resonance (MR) in the diagnosis and staging of solid cancers other than brain malignancies.

METHODS

We performed a systematic literature search on the PubMed/MEDLINE and EMBASE databases for meta-analyses assessing the accuracy of PET/CT and/or PET/MRI with [18F]FDG, somatostatin- receptor-targeting 68Ga-DOTA-peptides, 18F-labelled dihydroxyphenylalanine ([18F]DOPA), prostate-specific membrane antigen (PSMA)-targeted radioligands, and fibroblast activation protein inhibitors (FAPI) in the diagnosis/disease characterisation and staging of solid cancers other than brain tumours.

RESULTS

The literature search yielded 449 scientific articles. After screening titles and abstracts and applying inclusion and exclusion criteria, we selected 173 meta-analyses to assess the strength of evidence. One article was selected from references. Sixty-four meta-analyses were finally considered. The current evidence corroborates the role of [18F]FDG as the main player in molecular imaging; PSMA tracers are useful in staging and re-staging prostate cancer; somatostatin-targeting peptides (e.g. [68Ga]Ga- DOTA-TOC and -TATE) or [18F]DOPA are valuable in neuroendocrine tumours (NETs). FAPI has emerged in gastric cancer assessment. According to search and selection criteria, no satisfactory meta-analysis was selected for the diagnosis/detection of oesophageal cancer, the diagnosis/detection and N staging of small cell lung cancer and hepatic cell carcinoma, the diagnosis/detection and M staging of melanoma and Merkel cell carcinoma, cervical, vulvar and penis cancers, the N and M staging of lung and gastroenteropancreatic NET, testicular cancer, and chondrosarcoma, and the M staging of differentiated thyroid, bladder and anal cancers.

CONCLUSION

The comprehensive high-level evidence synthesised in the present umbrella review serves as a guiding compass for clinicians and imagers, aiding them in navigating the increasingly intricate seascape of PET examinations.

Advances in the diagnosis and follow-up of pleural lesions: a scoping review

INTRODUCTION

Pleural lesions may have heterogeneous presentation and causes. In recent years, there have been significant advances in pleural lesions diagnostics. The aim of this review is to provide an overview of the state-of-the-art, and recent updates for diagnostic modalities and monitoring regimes for pleural lesions.

AREAS COVERED

A literature search was conducted through PubMed and Web of Science for relevant articles published from 1 January 2000- 1 March 2023. This article critically appraises the radiological modalities and biopsy techniques that are employed in pleural lesions diagnostics, including chest radiography, thoracic ultrasound, computed tomography, F-fluorodeoxyglycose positron emission tomography, magnetic resonance imaging, percutaneous, and thoracoscopic pleural biopsies with reference to their strengths, limitations, and clinical use. The review asserts also the available literature regarding monitoring algorithms.

EXPERT OPINION

Despite the recent advances in the field, there are several key areas for improvement, including the development and validation of minimal invasive methods and tools for risk stratification, the integration of multi-omics technologies, the implementation of standardized, evidence-based diagnostic and monitoring guidelines and increased focus on research and patient-centric approaches. The broad establishment of dedicated pleural clinics may significantly assist toward this direction.

A PET-CT score for discriminating malignant from benign pleural effusions

BACKGROUND AND OBJECTIVES

The results of previous PET-CT studies are contradictory for discriminating malignant from benign pleural effusions. We purpose to develop a PET-CT score for differentiating between benign and malignant effusions.

PATIENTS AND METHODS

We conducted a prospective study of consecutive patients with pleural effusions undergoing PET-CT from October 2013 to October 2019 (referral cohort). PET-CT scan features evaluated using the SUV were: linear thickening; nodular thickening; nodules; masses; circumferential thickening; mediastinal and fissural pleural involvement; intrathoracic lymph nodes; pleural loculation; inflammatory consolidation; pleural calcification; cardiomegaly; pericardial effusion; bilateral effusion; lung mass; liver metastasis and other extra-pleural malignancy. The results were validated in an independent prospective cohort from November 2019 to June 2021.

RESULTS

One hundred and ninety-nine patients were enrolled in the referral cohort (91 with malignant effusions and 108 benign). The most useful parameters for the development of a PET-CT score were: nodular pleural thickening, pleural nodules with SUV>7.5, lung mass or extra pleural malignancy (10 points each), mammary lymph node with SUV>4.5 (5 points) and cardiomegaly (-1 point). With a cut-off value of >9 points in the referral cohort, the score established the diagnosis of malignant pleural effusion with sensitivity 87.9%, specificity 90.7%, positive predictive value 88.9%, negative predictive value 89.9%, positive likelihood ratio 7.81 and negative likelihood ratio 0.106. These results were validated in an independent prospective cohort of 75 patients.

CONCLUSIONS

PET-CT score was shown to provide relevant information for the identification of malignant pleural effusion.

Pleural Uptake Patterns in F18Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) Scans Improve the Identification of Malignant Pleural Effusions

BACKGROUND

The confirmation of malignant pleural effusions (MPE) requires an invasive procedure. Diagnosis can be difficult and may require repeated thoracentesis or biopsies. F18Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) can characterize the extent of malignant involvement in areas of increased uptake. Patterns of uptake in the pleura may be sufficient to obviate the need for further invasive procedures.

METHODS

This is a retrospective review of patients with confirmed malignancy and suspected MPE. Patients who underwent diagnostic thoracentesis with cytology and contemporaneous FDG-PET were identified for analysis. Some underwent confirmatory pleural biopsy. The uptake pattern on FDG-PET underwent blinded review and was categorized based on the pattern of uptake.

RESULTS

One hundred consecutive patients with confirmed malignancy, suspected MPE and corresponding FDG-PET scans were reviewed. MPE was confirmed in 70 patients with positive pleural fluid cytology or tissue pathology. Of the remaining patients, 15 had negative cytopathology, 14 had atypical cells and 1 had reactive cells. Positive uptake on FDG-PET was noted in 76 patients. The concordance of malignant histology and positive FDG-PET occurred in 58 of 76 patients (76%). Combining histologically confirmed MPE with atypical cytology, positive pleural FDG-PET uptake had a positive predictive value of 91% for MPE. An encasement pattern had a 100% PPV for malignancy.

CONCLUSION

Positive FDG-PET pleural uptake represents an excellent method to identify MPE, especially in patients with an encasement pattern. This may eliminate the need for additional invasive procedures in some patients, even when initial pleural cytology is negative.

Differentiating malignant and benign pleural effusion in patients with lung cancer: an 18F-FDG PET/CT retrospectively study

Rationale

To explore the clinical role of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in differentiating malignant pleural effusion (MPE) from benign pleural effusion (BPE) in patients with lung cancer.

Methods

Over a 8-year period, we retrospectively reviewed PET/CT data of lung cancer patients with pleural effusion, with 237 participants enrolled for analysis. The nature of pleural effusion was confirmed using pleural cytology or biopsy. MPE versus BPE comparison and multiple regression analysis were performed. Receiver operating characteristic (ROC) curve analysis was used for evaluating the diagnostic performance.

Results

Of the 237 participants, 170 had MPEs and 67 had BPEs. Compared with BPEs, MPEs had higher pleural SUVmax and thicker pleura and were more common among non-small cell lung cancers, peripheral tumors, and women (p < 0.05). BPEs had larger and higher ¹⁸F-FDG uptake thoracic lymph nodes and more complications of pneumonia (p < 0.05) than MPEs. Multiple regression analysis was used to identify the pleural SUVmax (odds ratio, OR = 38.8), sex (OR = 0.033), and mediastinal lymphoid node size (OR = 0.86) as independent risk factors for MPEs. The sensitivity, specificity, and area under the ROC curve (AUC) in the combined ROC curve analysis by using the three factors were 95.3%, 95.5%, and 0.989, respectively.

Conclusion

¹⁸F-FDG PET/CT integrated imaging is an effective non-invasive method for differential diagnosis of MPE in patients with lung cancer. Pleural SUVmax combined with thoracic lymph nodes and sex has high diagnostic value.

Clinical Value of Surveillance 18F-fluorodeoxyglucose PET/CT for Detecting Unsuspected Recurrence or Second Primary Cancer in Non-Small Cell Lung Cancer after Curative Therapy

Simple Summary

Non-small cell lung cancer (NSCLC) patients are at considerable risk of recurrence or second primary cancer (SPC) after curative therapy. The utility of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) surveillance to detect recurrent lesions in NSCLC patients without suspicion of recurrence has not been established. The aim of our retrospective study was to evaluate the diagnostic value of surveillance FDG PET/CT for detecting clinically unsuspected recurrence or SPC in patients with NSCLC after curative therapy. In a cohort of 2684 NSCLC patients after curative therapy, surveillance FDG PET/CT showed good diagnostic efficacy for detecting clinically unexpected recurrence or SPC. Furthermore, the diagnostic performance was improved in subgroups of patients with advanced stage prior to curative therapy, PET/CT scans performed within 3 years after curative-intent therapy, and curative surgery. Surveillance PET/CT can be more useful when performed soon after therapy in curative surgery recipients and those with an advanced disease stage considering its diagnostic efficacy and yield.

Abstract

We evaluated the diagnostic value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT surveillance for detecting clinically unsuspected recurrence or second primary cancer (SPC) in patients with non-small cell lung cancer (NSCLC) after curative therapy. A total of 4478 surveillance FDG PET/CT scans from 2864 NSCLC patients without suspicion of recurrence after curative therapy were reviewed retrospectively. In 274 of 2864 (9.6%) patients, recurrent NSCLC or SPC was found by surveillance PET/CT during clinical follow-up. Surveillance PET/CT scans showed sensitivity of 98.9% (274/277), specificity of 98.1% (4122/4201), accuracy of 98.2% (4396/4478), positive predictive value (PPV) of 77.6% (274/353), and negative predictive value of 99.9% (4122/4125). The specificity and accuracy in the curative surgery group were significantly higher than those in the curative radiotherapy group. PPV was significantly improved in subgroups of patients with advanced stage prior to curative therapy, PET/CT scans performed within 3 years after curative-intent therapy, and curative surgery. FDG PET/CT surveillance showed good diagnostic efficacy for detecting clinically unexpected recurrence or SPC in NSCLC patients after curative therapy. It can be more useful when performed soon after therapy in curative surgery recipients and those with an advanced disease stage considering its diagnostic efficacy and yield.

Current Roles of PET/CT in Thymic Epithelial Tumours: Which Evidences and Which Prospects? A Pictorial Review

Simple Summary

Thymic epithelial tumours are uncommon malignancies. Histologically, they may be distinguished in different subtypes and different relapse risk classes. Surgery, sometimes after induction therapy, stays the best treatment option, and long-term results depend on the disease stage and completeness of resection. In this context, ¹⁸F FDG PET CT scan has been reported to play different roles in the care strategy of thymic epithelial tumours. In the present review, we analyse current evidences, the use of this imaging tool and future application prospects.

Abstract

Background: The use of ¹⁸F FDG PET/CT scan in thymic epithelial tumours (TET) has been reported in the last two decades, but its application in different clinical settings has not been clearly defined. Methods: We performed a pictorial review of pertinent literature to describe different roles and applications of this imaging tool to manage TET patients. Finally, we summarized future prospects and potential innovative applications of PET in these neoplasms. Results: ¹⁸FFDG PET/CT scan may be of help to distinguish thymic hyperplasia from thymic epithelial tumours but evidences are almost weak. On the contrary, this imaging tool seems to be very performant to predict the grade of malignancy, to a lesser extent pathological response after induction therapy, Masaoka Koga stage of disease and long-term prognosis. Several other radiotracers have some application in TETs but results are limited and almost controversial. Finally, the future of PET/CT and theranostics in TETs is still to be defined but more detailed analysis of metabolic data (such as texture analysis applied on thymic neoplasms), along with promising preclinical and clinical results from new “stromal PET tracers”, leave us an increasingly optimistic outlook. Conclusions: PET plays different roles in the management of thymic epithelial tumours, and its applications may be of help for physicians in different clinical settings.

Positron emission tomography-computed tomography (PET-CT) in suspected malignant pleural effusion. An updated systematic review and meta-analysis

The role of PET and integrated PET-CT in the diagnostic workup of suspected malignant pleural effusions is unknown. Earlier systematic reviews (published 2014 and 2015) both included pleural pathology without effusion, and reached contradictory conclusions. Five studies have been published since the latest review. This systematic review and meta-analysis aims to summarise the evidence of PET and integrated PET-CT in predicting pleural malignancy in patients suspected of having malignant pleural effusions. A meta-analysis based on a systematic literature search in Cochrane Library, Medline, EMBASE and Clinicaltrials.gov was performed. Diagnostic studies evaluating the performance of PET or PET-CT in patients with suspected malignant pleural effusion, using pleural fluid cytology or histopathology as the reference test, and presenting sufficient data for constructing a 2x2 table were included. The quality of the studies was assessed by the Quality Assessment of Diagnostic Accuracy Studies-2 score. Subgroup analyses on image modality, interpretation method and known malignancy status pre index-test application were planned. Seven studies with low risk of bias were included. The pooled ability to separate benign from malignant effusions varied with image modality, interpretation method and known malignancy status pre index-test application. In studies using PET-CT, visual/qualitative image analysis was superior to semi-quantitative with positive (LR + ) and negative likelihood ratio (LR-) of 9.9 (4.5-15.3) respectively 0.1 (0.1-0.2). There was considerable heterogeneity among studies. In conclusion, visual/qualitative image analysis of integrated PET-CT seems to add relevant information in the work-up of suspected malignant pleural effusions with LR + and LR- close to rigorous pre-set cut-offs of > 10 and < 0.1. However, the quality of evidence was low due to inter-study heterogeneity, and inability to assess meta-bias. Clinical Trial Registration: The protocol was uploaded to the PROSPERO database (CRD42020213319) on the 13th of October 2020.

EGFR-specific single-chain variable fragment antibody-conjugated Fe3O4/Au nanoparticles as an active MRI contrast agent for NSCLC

Overexpression of epidermal growth factor receptor (EGFR) is closely associated with a poor prognosis in non-small cell lung cancer (NSCLC), thus making it a promising biomarker for NSCLC diagnosis. Here, we conjugated a single-chain antibody (scFv) targeting EGFR with Fe₃O₄/Au nanoparticles to form an EGFR-specific molecular MRI bioprobe (scFv@Fe₃O₄/Au) to better detect EGFR-positive NSCLC tumors in vivo. In vitro, we demonstrated that the EGFR-specific scFv could specifically deliver Fe₃O₄/Au to EGFR-positive NSCLC cells. In vivo experiments showed that the accumulation of scFv@Fe₃O₄/Au in tumor tissue was detectable by magnetic resonance imaging (MRI) at the indicated time points after systemic injection. The T2W signal-to-noise ratio (SNR) of EGFR-positive SPC-A1 tumors was significantly decreased after scFv@Fe₃O₄/Au injection, which was not observed in the tumors of mice injected with BSA@Fe₃O₄/Au. Furthermore, transmission electron microscopy (TEM) analysis showed the specific localization of scFv@Fe₃O₄/Au in the SPC-A1 tumor cell cytoplasm. Collectively, the results of our study demonstrated that scFv@Fe₃O₄/Au might be a useful probe for the noninvasive diagnosis of EGFP-positive NSCLC.

Diagnostic Performance of PET or PET/CT with Different Radiotracers in Patients with Suspicious Lung Cancer or Pleural Tumours according to Published Meta-Analyses

Purpose

Several meta-analyses have reported data about the diagnostic performance of positron emission tomography or positron emission tomography/computed tomography (PET or PET/CT) with different radiotracers in patients with suspicious lung cancer (LC) or pleural tumours (PT). This review article aims at providing an overview on the recent evidence-based data in this setting.

Methods

A comprehensive literature search of meta-analyses published in PubMed/MEDLINE and Cochrane Library database from January 2010 through March 2020 about the diagnostic performance of PET or PET/CT with different radiotracers in patients with suspicious LC or PT was performed. This combination of keywords was used: (A) “PET” OR “positron emission tomography” AND (B) “lung” OR “pulmonary” OR “pleur^∗” AND (C) meta-analysis. Only meta-analyses on PET or PET/CT in patients with suspicious LC or PT were selected.

Results

We have summarized the diagnostic performance of PET or PET/CT with fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) and other radiotracers taking into account 17 meta-analyses. Evidence-based data demonstrated a good diagnostic performance of ¹⁸F-FDG PET or PET/CT for the characterization of solitary pulmonary nodules (SPNs) or pleural lesions with overall higher sensitivity than specificity. Evidence-based data do not support the routine use of dual time point (DTP) ¹⁸F-FDG PET/CT or fluorine-18 fluorothymidine (¹⁸F-FLT) PET/CT in the differential diagnosis of SPNs. Even if ¹⁸F-FDG PET/CT has high sensitivity and specificity as a selective screening modality for LC, its role in this setting remains unknown.

Conclusions

Evidence-based data about the diagnostic performance of PET/CT with different radiotracers for suspicious LC or PT are increasing, with good diagnostic performance of ¹⁸F-FDG PET/CT. More prospective multicenter studies and cost-effectiveness analyses are warranted.

Comparison of cytology, chest computed and positron emission tomography findings in malignant pleural effusion from lung cancer

Background

Malignant pleural effusion (MPE) is a common medical problem in lung cancer (LC). Pleural fluid cytology (PFC), chest computed tomography (CCT) and positron emission tomography (PET) findings are helpful as first line approach. The objectives of this study were to evaluate whether there is a correlation between PFC, CCT and PET in patients with MPE due to LC.

Methods

We selected patients from our electronic files. Data of PFC, pleural biopsy (PB), CCT and PET have been recorded and analyzed.

Results

A total of 101 consecutive patients (66 males, 65.3%) with a mean age of 66.2±31 years were selected. Types of LC were adenocarcinoma in 71 patients (70.2%), squamous in 13 (12.8%), small-cell in 12 (11.8%) and large cell in 5 (4.9%). CCT showed nodules in 6 (5.9%), pleural thickening in 8 (7.9%) and both in 17 (16.8%) patients. PFC was positive in 55/91 thoracentesis (60.4%) and 32/52 thoracoscopy (61.5%), while PB in 38/40 performed (95%). PET fixation was found in 32/47 (68%) patients who had MPE at diagnosis. When we associate PFC to CCT and PET findings, the yield in our study becomes 90%. No correlation was observed between CCT findings and PFC (P=0.62) between PFC and PET fixation (P=0.63) or between CCT and PET (P=0.06).

Conclusions

In our cohort of LC patients with MPE, we observed a high sensitivity for PFC, while in most of the cases no findings were observed in CCT. PET had a relative low sensitivity. However, when all 3 methods were combined the yield was 90%.

SEOM-SERAM-SEMNIM guidelines on the use of functional and molecular imaging techniques in advanced non-small-cell lung cancer

Imaging in oncology is an essential tool for patient management but its potential is being profoundly underutilized. Each of the techniques used in the diagnostic process also conveys functional information that can be relevant in treatment decision making. New imaging algorithms and techniques enhance our knowledge about the phenotype of the tumor and its potential response to different therapies. Functional imaging can be defined as the one that provides information beyond the purely morphological data, and include all the techniques that make it possible to measure specific physiological functions of the tumor, whereas molecular imaging would include techniques that allow us to measure metabolic changes. Functional and molecular techniques included in this document are based on multi-detector computed tomography (CT), 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET), magnetic resonance imaging (MRI), and hybrid equipments, integrating PET with CT (PET/CT) or MRI (PET-MRI). Lung cancer is one of the most frequent and deadly tumors although survival is increasing thanks to advances in diagnostic methods and new treatments. This increased survival poises challenges in terms of proper follow-up and definitions of response and progression, as exemplified by immune therapy-related pseudoprogression. In this consensus document, the use of functional and molecular imaging techniques will be addressed to exploit their current potential and explore future applications in the diagnosis, evaluation of response and detection of recurrence of advanced NSCLC.

SEOM-SERAM-SEMNIM guidelines on the use of functional and molecular imaging techniques in advanced non-small-cell lung cancer

Imaging in oncology is an essential tool for patient management but its potential is being profoundly underutilized. Each of the techniques used in the diagnostic process also conveys functional information that can be relevant in treatment decision-making. New imaging algorithms and techniques enhance our knowledge about the phenotype of the tumor and its potential response to different therapies. Functional imaging can be defined as the one that provides information beyond the purely morphological data, and include all the techniques that make it possible to measure specific physiological functions of the tumor, whereas molecular imaging would include techniques that allow us to measure metabolic changes. Functional and molecular techniques included in this document are based on multi-detector computed tomography (CT), 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET), magnetic resonance imaging (MRI), and hybrid equipments, integrating PET with CT (PET/CT) or MRI (PET-MRI). Lung cancer is one of the most frequent and deadly tumors although survival is increasing thanks to advances in diagnostic methods and new treatments. This increased survival poises challenges in terms of proper follow-up and definitions of response and progression, as exemplified by immune therapy-related pseudoprogression. In this consensus document, the use of functional and molecular imaging techniques will be addressed to exploit their current potential and explore future applications in the diagnosis, evaluation of response and detection of recurrence of advanced NSCLC.

State-of-the-art: Radiological investigation of pleural disease

Pleural disease is common. Radiological investigation of pleural effusion, thickening, masses, and pneumothorax is key in diagnosing and determining management. Conventional chest radiograph (CXR) remains as the initial investigation of choice for patients with suspected pleural disease. When abnormalities are detected, thoracic ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) can each play important roles in further investigation, but appropriate modality selection is critical. US adds significant value in the identification of pleural fluid and pleural nodularity, guiding pleural procedures and, increasingly, as "point of care" assessment for pneumothorax, but is highly operator dependent. CT scan is the modality of choice for further assessment of pleural disease: Characterising pleural thickening, some pleural effusions and demonstration of homogeneity of pleural masses and areas of fatty attenuation or calcification. MRI has specific utility for soft tissue abnormalities and may have a role for younger patients requiring follow-up serial imaging. MRI and PET/CT may provide additional information in malignant pleural disease regarding prognosis and response to therapy. This article summarises existing techniques, highlighting the benefits and applications of these different imaging modalities and provides an up to date review of the evidence.

The role of computed tomography in assessing pleural malignancy prior to thoracoscopy

PURPOSE OF REVIEW

Computed tomography (CT) scanning is part of the routine diagnostic work up of patients with suspected pleural malignancy but has a wide variation in the reported sensitivity and specificity. This review was to appraise the recent literature on the utility of CT scanning.

RECENT FINDINGS

When investigating patients for suspected pleural malignancy, the sensitivity of a malignant CT report may be higher than previously reported (68%), but the specificity seems significantly lower (78%). The predictive value of CT scanning (on all patients with pleural effusions) may be increased using a CT scoring system. Recent meta-analyses of the utility of PET give differing opinions on the value of this imaging modality. Further work needs to be done to define its place in the diagnostic pathway.

SUMMARY

CT scoring systems may allow further risk stratification. However, a low negative predictive value of a 'negative' CT scan could lead to false reassurance and missed malignancy. PET/CT does not currently appear to add additional diagnostic value. Pulmonary emboli should be considered in all patients being investigated for clinically suspected malignant pleural disease. Respiratory physicians should be mindful of rare or unusual presentations.

The utility of 18F-FDG PET/CT in solitary fibrous tumors of the pleura

OBJECTIVE

To demonstrate the utility of (18)F-FDG PET/CT in the differentiation of benign and malignant solitary fibrous tumors of the pleura (SFTP).

MATERIALS AND METHODS

A retrospective review was performed on the (18)F-FDG PET/CT data from 17 patients with histopathologically diagnosed benign or malignant SFTP. The size, side of SFTP, presence of necrosis, calcification, pleural effusion, hilar lymphadenopathy (LAP), density on CT images (Hounsfield unit-HU), and (18)F-FDG uptake (SUVmax) were recorded and compared in order to detect malignant SFTP. Statistical significance was set as p<0.05.

RESULTS

The difference in size, presence of necrosis, and hilar LAP on CT images were statistically significant (p=0.004, p<0.001, p=0.015, respectively) in a comparison of benign and malignant SFTPs. The mean HU of benign SFTP was 46.16±5.52HU, and for malignant SFTP it was 35.03±4.61HU (p=0.003). The mean SUVmax was 3.02±1.02 for benign SFTP and 4.89±2.12 for malignant SFTP (p=0.021). A cut-off value of ≥7cm for size, ≤39.81HU for density, and ≥3.47 for SUVmax was obtained by ROC analysis for detecting malignant SFTP.

CONCLUSIONS

(18)F-FDG PET/CT may have a limited role in diagnosing malignant SFTP in suspected patients.

Comparative study of ¹⁸F-FDG-PET/CT imaging and serum hTERT mRNA quantification in cancer diagnosis

We have reported on the clinical usefulness of human telomerase reverse transcriptase (hTERT) mRNA quantification in sera in patients with several cancers. Positron emission tomography–computed tomography (PET/CT) using ¹⁸F-fluorodeoxyglucose (FDG) has recently become an excellent modality for detecting cancer. We performed a diagnostic comparative study of FDG-PET/CT and hTERT mRNA quantification in patients with cancer. Four hundred seventy subjects, including 125 healthy individuals and 345 outpatients with cancer who had received medical treatments for cancer in their own or other hospitals, were enrolled. The subjects were diagnosed by FDG-PET/CT, and we measured their serum hTERT mRNA levels using real-time RT-PCR, correlating the quantified values with the clinical course. In this prospective study, we statistically assessed the sensitivity and specificity, and their clinical significance. hTERT mRNA and FDG-PET/CT were demonstrated to be correlated with the clinical parameters of metastasis and recurrence (P < 0.001), and of recurrence and tumor number in cancer compared with noncancer patients, respectively. A multivariate analysis showed a significant difference in the detection by FDG-PET/CT, ¹⁸F-FDG uptake, the detection by hTERT mRNA, and age. The use of both FDG-PET/CT and hTERT mRNA resulted in a positivity of 94.4% (221/234) for the detection of viable tumor cells. FDG-PET/CT is superior to hTERT mRNA quantification in the early detection of cancer and combinative use of FDG-PET/CT and hTERT mRNA may improve the diagnostic accuracy of cancer.

Accuracy of fluorodeoxyglucose-PET imaging for differentiating benign from malignant pleural effusions: a meta-analysis

BACKGROUND

The role of fluorodeoxyglucose (FDG)-PET imaging for diagnosing malignant pleural effusions is not well defined. The aim of this study was to summarize the evidence for its use in ruling in or out the malignant origin of a pleural effusion or thickening.

METHODS

A meta-analysis was conducted of diagnostic accuracy studies published in the Cochrane Library, PubMed, and Embase (inception to June 2013) without language restrictions. Two investigators selected studies that had evaluated the performance of FDG-PET imaging in patients with pleural effusions or thickening, using pleural cytopathology or histopathology as the reference standard for malignancy. Subgroup analyses were conducted according to FDG-PET imaging interpretation (qualitative or semiquantitative), PET imaging equipment (PET vs integrated PET-CT imaging), and/or target population (known lung cancer or malignant pleural mesothelioma). Study quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2. We used a bivariate random-effects model for the analysis and pooling of diagnostic performance measures across studies.

RESULTS

Fourteen non-high risk of bias studies, comprising 407 patients with malignant and 232 with benign pleural conditions, met the inclusion criteria. Semiquantitative PET imaging readings had a significantly lower sensitivity for diagnosing malignant effusions than visual assessments (82% vs 91%; P = .026). The pooled test characteristics of integrated PET-CT imaging systems using semiquantitative interpretations for identifying malignant effusions were: sensitivity, 81%; specificity, 74%; positive likelihood ratio (LR), 3.22; negative LR, 0.26; and area under the curve, 0.838. Resultant data were heterogeneous, and spectrum bias should be considered when appraising FDG-PET imaging operating characteristics.

CONCLUSIONS

The moderate accuracy of PET-CT imaging using semiquantitative readings precludes its routine recommendation for discriminating malignant from benign pleural effusions.

Lung cancer coexisting with ipsilateral pleural effusion

SUMMARY 

Invasion beyond the elastic layer of the visceral pleura and/or diffuse pleural metastatic spread affects negatively survival in lung cancer. Presence of pleural effusion is also associated with poor prognosis, and image techniques can be of great help for diagnosis. When pleural fluid cytology is negative, thoracoscopy is advisable before attempting tumor resection, in order to detect unsuspected pleural metastases. If widespread pleural malignancy is confirmed, chemical pleurodesis using graded talc (with particles larger than 20 µm in diameter) is the best option, unless the lung is unable to re-expand. In this case, or when a previous pleurodesis has failed, or there is a short life expectancy, placement of a indwelling pleural catheter is the treatment of choice.