Prognostic value of SUVmax on 18F-fluorodeoxyglucose PET/CT scan in patients with malignant pleural mesothelioma

Predictive value of 18F-FDG PET/CT-based radiomics model for neoadjuvant chemotherapy efficacy in breast cancer: a multi-scanner/center study with external validation

PURPOSE

To develop and validate the predictive value of an 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) model for breast cancer neoadjuvant chemotherapy (NAC) efficacy based on the tumor-to-liver ratio (TLR) radiomic features and multiple data pre-processing methods.

METHODS

One hundred and ninety-three breast cancer patients from multiple centers were retrospectively included in this study. According to the endpoint of NAC, we divided the patients into pathological complete remission (pCR) and non-pCR groups. All patients underwent 18F-FDG PET/CT imaging before NAC treatment, and CT and PET images volume of interest (VOI) segmentation by manual segmentation and semi-automated absolute threshold segmentation, respectively. Then, feature extraction of VOI was performed with the pyradiomics package. A total of 630 models were created based on the source of radiomic features, the elimination of the batch effect approach, and the discretization method. The differences in data pre-processing approaches were compared and analyzed to identify the best-performing model, which was further tested by the permutation test.

RESULTS

A variety of data pre-processing methods contributed in varying degrees to the improvement of model effects. Among them, TLR radiomic features and Combat and Limma methods that eliminate batch effects could enhance the model prediction overall, and data discretization could be used as a potential method that can further optimize the model. A total of seven excellent models were selected and then based on the AUC of each model in the four test sets and their standard deviations, we selected the optimal model. The optimal model predicted AUC between 0.7 and 0.77 for the four test groups, with p-values less than 0.05 for the permutation test.

CONCLUSION

It is necessary to enhance the predictive effect of the model by eliminating confounding factors through data pre-processing. The model developed in this way is effective in predicting the efficacy of NAC for breast cancer.

Clinical application of AI-based PET images in oncological patients

Based on the advantages of revealing the functional status and molecular expression of tumor cells, positron emission tomography (PET) imaging has been performed in numerous types of malignant diseases for diagnosis and monitoring. However, insufficient image quality, the lack of a convincing evaluation tool and intra- and interobserver variation in human work are well-known limitations of nuclear medicine imaging and restrict its clinical application. Artificial intelligence (AI) has gained increasing interest in the field of medical imaging due to its powerful information collection and interpretation ability. The combination of AI and PET imaging potentially provides great assistance to physicians managing patients. Radiomics, an important branch of AI applied in medical imaging, can extract hundreds of abstract mathematical features of images for further analysis. In this review, an overview of the applications of AI in PET imaging is provided, focusing on image enhancement, tumor detection, response and prognosis prediction and correlation analyses with pathology or specific gene mutations in several types of tumors. Our aim is to describe recent clinical applications of AI-based PET imaging in malignant diseases and to focus on the description of possible future developments.

The efficacy of 18F-FDG PET/CT in monitoring disease progression in malignant pleural mesothelioma

OBJECTIVE

In the event of suspicion of malignant pleural mesothelioma (MPM) progression, imaging plays an important role. We aimed to evaluate the efficacy of ¹⁸F-FDG PET/CT in monitoring disease progression by comparing it with CT, and estimate median overall survival (OS) according to progression status with CT and ¹⁸F-FDG PET/CT.

MATERIALS AND METHODS

This was an observational, retrospective, single-institution study with MPM patients who had both ¹⁸F-FDG PET/CT and CT for monitoring disease progression from March 2009 to February 2020. Clinical features, radiological findings, and progression status according to CT [radiologic progression negative (RPN), radiologic progression positive (RPP)] and ¹⁸F-FDG PET/CT [metabolic progression negative (MPN), metabolic progression positive (MPP)] were recorded. The discrepancies and concordance between two methods were evaluated. The OS was estimated using the Kaplan-Meier method.

RESULTS

A total of 56 patients were included. There were thirty-one (55.3%) RPN and 25 (44.7%) RPP, while there were 26 (46.5%) MPN and 30 (53.5%) MPP. All RPP patients were also found to be MPP, however, among RPN, 5 patients (8.9% of all patients) were evaluated as MPP. The concordance between two methods in monitoring disease progression was very good (K = 0.423; p < 0.01). The OS was 26 ± 2.6 months in all patients. Kaplan-Meier curves between RPN and RPP, and between MPN and MPP did not show statistically significant differences (p = 0.56 and p = 0.25, respectively).

CONCLUSIONS

Both methods are equally acceptable in monitoring disease progression in MPM, even though ¹⁸F-FDG PET/CT detected more progression than CT did.

Clinical, Laboratory, Histological, Radiological, and Metabolic Features and Prognosis of Malignant Pleural Mesothelioma

Background: Malignant pleural mesothelioma (MPM) is an aggressive and rare malignant pleural tumor. Methods: MPM patients diagnosed in Beijing Chaoyang Hospital and Beijing Tongren Hospital were the focus of this study. We collected and analyzed the histological, radiological, and metabolic features of MPM patients. At the same time, Cox univariable and multivariable analyses were used to explore the laboratory risk factors affecting the prognosis of MPM patients. Results: A total of 129 MPM patients were included in this study. MPM includes three main histological subtypes: epithelioid, sarcomatoid and biphasic. Among them, epithelial subtypes accounted for the highest proportion. Calretinin, Wilms' tumor gene (WT1), cytokeratin 5/6 (CK5/6), and D2-40 were the most useful mesothelial markers to support a MPM diagnosis. The imaging features of MPM patients are pleural thickening and pleural effusion. In PET-CT, the affected pleura showed obvious high uptake of tracer, and the degree was related to the specific subtype. The median follow-up time was 55.0 (30.0, 94.0) months. A total of 92 (71.3%) patients died during follow-up. The median survival time of patients was 21.0 (9.0, 48.0) months. The Cox multivariable analysis showed that age [hazard ratio (HR), 1.824; 95% confidence interval (CI) 1.159-2.872; p = 0.009; uncorrected], ESR (HR, 2.197; 95% CI 1.318-3.664; p = 0.003; with Bonferroni correction), lymphocytes (HR, 0.436; 95% CI 0.258-0.737; p = 0.002; with Bonferroni correction), platelets (HR, 1.802; 95% CI 1.084-2.997; p = 0.023; uncorrected) and total protein (HR, 0.625; 95% CI 0.394-0.990; p = 0.045; uncorrected) were independent risk factors for prognosis, after adjusting for confounding factors. Conclusions: Age, ESR, lymphocytes, platelets and total protein may be related to the prognosis of MPM patients. Summarizing the histological, radiological, and metabolic features of MPM patients in the two centers can increase clinicians' understanding of this rare tumor.

Old Borders and New Horizons in Multimodality Imaging of Malignant Pleural Mesothelioma

BACKGROUND

The purpose of this article is to describe the various imaging techniques involved in detection, staging, and preoperative planning in malignant pleural mesothelioma (MPM) focusing on new imaging modalities.

METHODS

For this purpose, first a brief summary of the etiology of MPM is given. Second, not only the commonly known, but also novel imaging modalities used in MPM will be discussed.

RESULTS

A wide range of imaging methods, from conventional chest radiography, through computed tomography and hybrid imaging to radiomics and artificial intelligence, can be used to evaluate MPM.

CONCLUSION

Nowadays multimodality imaging is considered the cornerstone in MPM diagnosis and staging.

Prognostic value of maximum standard uptake value, metabolic tumour volume, and total lesion glycolysis of 18F-FDG PET/CT in patients with malignant pleural mesothelioma: a systematic review and meta-analysis

PURPOSE

Present work systematically reviewed relevant literature based on 18F-FDG PET parameters and conducted a meta-analysis to examine the prognostic value of maximal standard uptake value (SUVmax), total lesional glycolysis (TLG), and metabolic tumour volume (MTV) in the prognosis of malignant pleural mesothelioma (MPM).

METHODS

The relevant literature published in English were searched on PubMed, Cochrane Library, and EMBASE databases. We also evaluated the significance of SUVmax, TLG, and MTV in prognosis prediction using pooled hazard ratios (HRs).

RESULTS

The current study comprised 12 primary studies with a total of 1307 MPM cases. According to our results, the pooled HR (95% confidence interval [CI]) of increased SUVmax for overall survival (OS) was 1.30 (95% CI 1.13-1.49, P = 0.000), whereas the increased TLG was 1.81(95% CI 1.25-2.61, P = 0.089). The increased MTV was not significantly related to OS (1.14 [95% CI 0.87-1.50, P = 0.18]).However, study design-stratified subgroup analysis suggested that differences in OS of retrospective and prospective subgroups were statistically significant, and no significant heterogeneity among different studies was observed.

CONCLUSION

Based on the findings from the present work, PET/CT can significantly affect the prognosis prediction in MPM cases. Also, the increased SUVmax and TLG values predict an increased risk of mortality.

The Prognostic Value of 18F-FDG PET Imaging at Staging in Patients with Malignant Pleural Mesothelioma: A Literature Review

Malignant pleural mesothelioma (MPM) is an aggressive malignancy, frequently diagnosed at locally-advanced/metastatic stages. Due to a very poor prognosis and limited treatment options, the need to identify new prognostic markers represents a great clinical challenge. The prognostic role of metabolic information derived from Positron Emission Tomography (PET) with ¹⁸F-Fluoro-deoxy-glucose (¹⁸F-FDG) has been investigated in different MPM settings, however with no definitive consensus. In this comprehensive review, the prognostic value of FDG-PET imaging exclusively performed at staging in MPM patients was evaluated, conducting a literature search on PubMed/MEDLINE from 2010 to 2020. From the 19 selected studies, despite heterogeneity in several aspects, staging FDG-PET imaging emerges as a valuable prognostic biomarker, with higher tumor uptake predictive of worse prognosis, and with volumetric metabolic parameters like Metabolic Tumor Volume, (MTV) and Total Lesion Glycolisis (TLG) performing better than SUVmax. However, PET uptake parameters were not always confirmed as independent prognostic factors, especially in patients previously treated with pleurodesis and with a non-epithelioid histotype. Future prospective studies in larger and clinically homogeneous populations, and using more standardized methods of PET images analysis, are needed to further validate the value of staging FDG-PET in the prognostic MPM stratification, with a potential impact on better patient-tailored treatment planning, in the perspective of personalized medicine.

False-Negative 18F-Fluorodeoxyglucose PET/CT in Malignant Pleural Mesothelioma

We report a diagnostically challenging case of a 77-year-old man who presented with shortness of breath and was found to have a large right hydropneumothorax with collapse of the right lung. A malignancy was suspected, but pleural fluid cytology and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT imaging were negative. He then underwent video-assisted thoracoscopy with biopsies of the pleura and chest wall which revealed malignant pleural mesothelioma (MPM). Older patients with early stage MPM are more likely to have false-negative FDG PET/CT results. Pleural biopsy is essential when there is clinical suspicion for mesothelioma, even with negative initial FDG PET imaging.

Prognostic value of metabolic parameters on 18F-fluorodeoxyglucose positron tomography/computed tomography in classical rectal adenocarcinoma

We aimed to investigate the prognostic value of the metabolic parameters of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in classical rectal adenocarcinoma (CRAC). We retrospectively reviewed 149 patients with CRAC who underwent preoperative 18F-FDG PET/CT at initial diagnosis followed by curative surgical resection. 18F-FDG PET/CT metabolic parameters including maximum standardized uptake value (SUVmax), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) for disease-free survival (DFS) and overall survival (OS) were evaluated for prognostic significance by univariate and multivariate analyses, along with conventional risk factors including pathologic T (pT) stage, lymph node (LN) metastasis, lymphovascular invasion (LVI), perineural invasion (PNI), and preoperative carcinoembryonic antigen (CEA) level. On univariate analysis, high pT stage, positive LN metastasis, LVI, PNI, MTV, and TLG were significant prognostic factors affecting DFS (all P < 0.05), while CEA level, high pT stage, positive LN metastasis, LVI, PNI, MTV, and TLG affected OS (all P < 0.05). On multivariate analysis, positive LN metastasis, LVI, MTV, and TLG were independent prognostic factors affecting DFS (all P < 0.05), while CEA level, positive LN metastasis, and MTV affected OS (all P < 0.05). Thus, the volume-based metabolic parameters from preoperative 18F-FDG PET/CT scans are independent prognostic factors in patients with CRAC.

Preoperative Identification of Benefit from Surgery for Malignant Pleural Mesothelioma

In the absence of standardized treatment algorithms for patients with malignant pleural mesothelioma, one of the main difficulties remains patient allocation to therapies with potential benefit. This article discusses clinical, radiologic, pathologic, and molecular prognostic factors as well as genetic background leading to preoperative identification of benefit from surgery, which have been investigated over the past years to simplify and at the same time specify patient selection for surgical treatment.