Diagnostic performance of 18-F-FDG-PET-CT in adrenal lesions using histopathology as reference standard

[18F]FDG-PET/CT in adrenal lesions: diagnostic performance in different clinical settings

PURPOSE

Data regarding [18F]FDG-PET/CT for the characterization of adrenal lesions are limited. Most of the studies proposed the tumor-to-liver maximum standardized uptake values (SUVratio) > 1.5 as the best cut off to predict malignancy. The aim of the study was to calculate the optimum cut off in a heterogeneous population with adrenal lesions and evaluate the diagnostic performance SUVratio >1.5.

PATIENTS AND METHODS

Retrospective analysis of adrenal lesions undergoing [18F]FDG-PET/CT (2013-2022) for different reasons (atypical adrenal incidentalomas, extra adrenal tumor staging). The diagnosis of benignity was assessed by: (i) histology; (ii) stability or minimal diameter increase (<20%/<5 mm) on 12-months follow-up for non-operated patients. The optimal SUVratio and performance of SUVratio >1.5 were calculated by ROC curves.

RESULTS

Forty-two consecutive lesions (diameter 36.1 ± 20.3 mm, 6 bilateral) underwent [18F]FDG-PET/CT (19F, age 61.2 ± 11.7 years). Twenty-nine lesions were benign, 11 malignant [8 metastases (2 bilateral) and 1 adrenocortical carcinoma (ACC)] and 2 pheochromocytomas. The SUVratio cut-off in our population was 1.55 (Sn 100%, Sp 73.7%, AUC 0.868), with similar values excluding pheochromocytomas and metastases (SUVratio cut-off 1.49, Sn 100%, Sp 96.3%, AUC 0.988). The SUVratio cut-off of 1.5 showed 100% Sn, 87% Sp, 73% PPV, and 100% NPV.

CONCLUSION

[18F]FDG-PET/CT could help in decision making process avoiding unnecessary surgery. The SUVratio cut-off of 1.5 has a good performance in a heterogenous population.

The Diagnostic Value of 18F-FDG PET/CT Scan in Characterizing Adrenal Tumors

CONTEXT

Imaging plays an important role in the characterization of adrenal tumors, but findings might be inconclusive. The clinical question is whether 18F fluodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is of diagnostic value in this setting.

OBJECTIVE

This meta-analysis was aimed at the diagnostic value of 18F-FDG PET/CT in differentiating benign from malignant adrenal tumors discovered either as adrenal incidentaloma or during staging or follow-up of oncologic patients.

DATA SOURCES

PubMed, EMBASE, Web of Science, and Cochrane Library were searched to select articles between 2000 and 2021.

STUDY SELECTION

We included studies describing the diagnostic value of 18F-FDG PET/CT in adult patients with an adrenal tumor. Exclusion criteria were 10 or fewer participants, insufficient data on histopathology, clinical follow-up, or PET results. After screening of title and abstract by 2 independent reviewers, 79 studies were retrieved, of which 17 studies met the selection criteria.

DATA EXTRACTION

Data extraction using a protocol and quality assessment according to QUADAS-2 was performed independently by at least 2 authors.

DATA SYNTHESIS

A bivariate random-effects model was applied using R (version 3.6.2.). Pooled sensitivity and specificity of 18F-FDG PET/CT for identifying malignant adrenal tumors was 87.3% (95% CI, 82.5%-90.9%) and 84.7% (95% CI, 79.3%-88.9%), respectively. The pooled diagnostic odds ratio was 9.20 (95% CI, 5.27-16.08; P < .01). Major sources of heterogeneity (I2, 57.1% [95% CI, 27.5%-74.6%]) were in population characteristics, reference standard, and interpretation criteria of imaging results.

CONCLUSIONS

18F-FDG PET/CT had good diagnostic accuracy for characterization of adrenal tumors. The literature, however, is limited, in particular regarding adrenal incidentalomas. Large prospective studies in well-defined patient populations with application of validated cutoff values are needed.

The F-18 FDG PET/CT evaluation of the metastatic adrenal lesions of the non-lung cancer tumors compared with pathology results

Background

The aim of this study was to evaluate the role of F-18 FDG PET/CT imaging in the diagnosis of primary and metastatic adrenal tumors that originate from non-lung cancer primary tumors.

Results

F-18 FDG PET/CT images of patients (8 male and 6 female; mean: 55.36 ± 16.2 years old) who attended with the diagnosis of primary or adrenal metastatic lesions other than lung cancer metastasis were evaluated in a retrospective manner. The diameter of the adrenal lesions was mean: 23.93 ± 36.6 mm with SUVmax levels of mean: 9.98 ± 7.8. The primary site of 2/3 of the patients with unknown primary was the adrenal gland, and in one of the patients primary tumor remained unknown during follow-up.

Conclusions

According to the results of this study, F-18 FDG PET/CT has high diagnostic performance in the diagnosis of the adrenal gland primary and metastatic lesions, which originate from non-lung cancer tumors. Further studies in the larger series are warranted.

Efficacy of PET-CT in the prediction of metastatic adrenal masses that are detected on follow-up of the patients with prior nonadrenal malignancy: A nationwide multicenter case-control study

Metastasis is the second most common type of adrenal gland mass. In patients undergoing follow-up for nonadrenal malignancy, adrenalectomy is performed when metastasis to adrenal gland is suspected on the basis of positron emission tomography-computed tomography (PET-CT) imaging. This study investigated the efficacy of PET-CT in the discrimination of metastatic lesions from nonmetastatic lesions in the adrenal glands. In this multicentric study, data was collected from enrolled centers. Forty-one patients who underwent surgery for suspected adrenal metastases were evaluated retrospectively. The following data types were collected: demographic, primary tumor, maximum standardized uptake value of adrenal mass (a-SUVx) and detectability in computed tomography and/or magnetic resonance imaging, and specimen size and histopathology. Six patients were excluded due to unavailability of PET-CT reports and 4 for being primary adrenal malignancy. The rest were divided into 2 groups (metastatic: n = 17, 55% and nonmetastatic: n = 14, 45%) according to histopathology reports. There was no statistical difference between the analyzed values, except the a-SUVx (P < .05). The a-SUVx cutoff value was defined as 5.50 by receiver operating characteristic curves and compared with literature. There was no statistical difference when each group was divided as low and high (P > .05). It was found that PET-CT was able to discriminate metastatic lesions from primary benign lesions (P = .022). PET-CT can discriminate primary benign lesions and metastatic lesions by cutoff 5.5 value for a-SUVx.

European Society of Endocrinology Clinical Practice Guidelines on the management of adrenocortical carcinoma in adults, in collaboration with the European Network for the Study of Adrenal Tumors

Adrenocortical carcinoma (ACC) is a rare and in most cases steroid hormone-producing tumor with variable prognosis. The purpose of these guidelines is to provide clinicians with best possible evidence-based recommendations for clinical management of patients with ACC based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. We predefined four main clinical questions, which we judged as particularly important for the management of ACC patients and performed systematic literature searches: (A) What is needed to diagnose an ACC by histopathology? (B) Which are the best prognostic markers in ACC? (C) Is adjuvant therapy able to prevent recurrent disease or reduce mortality after radical resection? (D) What is the best treatment option for macroscopically incompletely resected, recurrent or metastatic disease? Other relevant questions were discussed within the group. Selected Recommendations: (i) We recommend that all patients with suspected and proven ACC are discussed in a multidisciplinary expert team meeting. (ii) We recommend that every patient with (suspected) ACC should undergo careful clinical assessment, detailed endocrine work-up to identify autonomous hormone excess and adrenal-focused imaging. (iii) We recommend that adrenal surgery for (suspected) ACC should be performed only by surgeons experienced in adrenal and oncological surgery aiming at a complete en bloc resection (including resection of oligo-metastatic disease). (iv) We suggest that all suspected ACC should be reviewed by an expert adrenal pathologist using the Weiss score and providing Ki67 index. (v) We suggest adjuvant mitotane treatment in patients after radical surgery that have a perceived high risk of recurrence (ENSAT stage III, or R1 resection, or Ki67 >10%). (vi) For advanced ACC not amenable to complete surgical resection, local therapeutic measures (e.g. radiation therapy, radiofrequency ablation, chemoembolization) are of particular value. However, we suggest against the routine use of adrenal surgery in case of widespread metastatic disease. In these patients, we recommend either mitotane monotherapy or mitotane, etoposide, doxorubicin and cisplatin depending on prognostic parameters. In selected patients with a good response, surgery may be subsequently considered. (vii) In patients with recurrent disease and a disease-free interval of at least 12 months, in whom a complete resection/ablation seems feasible, we recommend surgery or alternatively other local therapies. Furthermore, we offer detailed recommendations about the management of mitotane treatment and other supportive therapies. Finally, we suggest directions for future research.

Advances in adrenal tumors 2018

This review aims to provide clinicians and researchers with a condensed update on the most important studies in the field during 2017. We present the academic output measured by active clinical trials and peer-reviewed published manuscripts. The most important and contributory manuscripts were summarized for each diagnostic entity, with a particular focus on manuscripts that describe translational research that have the potential to improve clinical care. Finally, we highlight the importance of collaborations in adrenal tumor research, which allowed for these recent advances and provide structures for future success in this scientific field.

Spatial Bayesian modeling of GLCM with application to malignant lesion characterization

The emerging field of cancer radiomics endeavors to characterize intrinsic patterns of tumor phenotypes and surrogate markers of response by transforming medical images into objects that yield quantifiable summary statistics to which regression and machine learning algorithms may be applied for statistical interrogation. Recent literature has identified clinicopathological association based on textural features deriving from gray-level co-occurrence matrices (GLCM) which facilitate evaluations of gray-level spatial dependence within a delineated region of interest. GLCM-derived features, however, tend to contribute highly redundant information. Moreover, when reporting selected feature sets, investigators often fail to adjust for multiplicities and commonly fail to convey the predictive power of their findings. This article presents a Bayesian probabilistic modeling framework for the GLCM as a multivariate object as well as describes its application within a cancer detection context based on computed tomography. The methodology, which circumvents processing steps and avoids evaluations of reductive and highly correlated feature sets, uses latent Gaussian Markov random field structure to characterize spatial dependencies among GLCM cells and facilitates classification via predictive probability. Correctly predicting the underlying pathology of 81% of the adrenal lesions in our case study, the proposed method outperformed current practices which achieved a maximum accuracy of only 59%. Simulations and theory are presented to further elucidate this comparison as well as ascertain the utility of applying multivariate Gaussian spatial processes to GLCM objects.