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

Our plain-English summary of The Prognostic Value of 18F-FDG PET Imaging at Staging in Patients with Malignant Pleural Mesothelioma: A Literature Review, by S. Taralli, R.G. Giancipoli, C. Caldarella, et al (Journal of Clinical Medicine, 2021).

The study

• Authors: S. Taralli, R.G. Giancipoli, C. Caldarella, V. Scolozzi, S. Ricciardi, G. Cardillo, M.L. Calcagni
• Journal: Journal of Clinical Medicine
• Published: 2021;11(1)
• Type of article: Review
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

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.

In plain English

This article was a literature review, not a new study of patients. The authors searched PubMed/MEDLINE for studies from January 2010 to December 2020 on whether an 18F-FDG PET scan done at staging (at first diagnosis, before treatment) could predict outcome in people with malignant pleural mesothelioma. The review did not study asbestos exposure. They included 19 studies, all but two retrospective, and 1472 patients in total were considered. In 17 of the 19 studies, higher tumor uptake on the scan went with a worse prognosis. Two studies found no prognostic role. Volume-based measures did better than the standard SUVmax measure in 5 of the 8 studies that tested both. Cut-off values varied widely between studies. In 9 of 19 studies, scan measures were not always confirmed as independent factors or showed no link with survival. The authors concluded that staging PET has prognostic value. They cautioned that scan measures were not always independent factors, especially after previous pleurodesis and in non-epithelioid tumors, and that larger, standardized prospective studies are needed. They cited small, mostly retrospective and varied studies as limitations.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Literature review of published studies (PubMed/MEDLINE search, January 2010 to December 2020)
• Who was studied: 19 published studies of patients with malignant pleural mesothelioma who had 18F-FDG PET at staging. Of 1552 enrolled patients, 1472 had data for PET prognostic assessment. All but two studies were retrospective. The text gives study sizes of 23 to 188 patients, but Table 1 lists studies enrolling 21 (Kaira et al.) and 191 (Billé et al.) patients. Only 5 of 19 studies had more than 100 patients.
• Exposure: Not asbestos. The review examined 18F-FDG PET imaging performed at staging and measures of tumor uptake (SUVmax, SUVmean, SUVpeak, metabolic tumor volume, total lesion glycolysis). It did not examine fiber types, products, jobs or doses.
• Main results:
  • In 17 of the 19 studies, staging PET was a prognostic marker, with higher tumor uptake predicting worse prognosis.
  • Two studies (Genestreti et al., 27 patients; Özyürek et al., 67 patients) found no prognostic role. In Özyürek et al., median survival was 23 months with SUVmax below 5 versus 13 months with SUVmax 5 or above, but the difference was not statistically significant.
  • Among the 8 studies that tested both SUV-based and volume-based measures, the volume-based measures (MTV and TLG) showed better prognostic value than SUV in 5.
  • Optimal cut-off values varied widely across studies. The text gives ranges of 3.5 to 10.1 for SUVmax, 112 to 755 cm3 for MTV, and 525 to 2914 for TLG.
  • In 9 of the 19 included studies (almost 50%), PET uptake measures were either not always confirmed as independent prognostic factors or showed no relationship with survival.
  • Previous talc pleurodesis, which can raise pleural FDG uptake through inflammation, and non-epithelioid histology weakened the prognostic value of PET in some studies. In Lim et al., SUVmax was associated with overall survival in epithelioid but not non-epithelioid patients.
• The authors' conclusion: The authors concluded that their review supports staging 18F-FDG PET as a prognostic predictor in malignant pleural mesothelioma, with higher uptake predicting worse prognosis. They found that volume-based measures seem better than SUVmax. They noted that PET measures were not always confirmed as independent factors, especially in patients previously treated with pleurodesis and with non-epithelioid tumors, and that larger prospective, standardized studies are needed.
• Limitations the authors state:
  • The included studies were small and mostly retrospective, and they differed in clinical characteristics (stage, treatment, pleurodesis) and methods.
  • Different tumor contouring methods may have affected the MTV and TLG analyses.
  • Too few studies evaluated both MTV and TLG to compare them reliably.

Topics

Medical terms in this study, explained in our Lexicon: Staging, Pleural Mesothelioma, Prognosis, Biomarker, Pleurodesis, Non-epithelioid.

Related studies

• Prognostic value of 18F-FDG standard uptake value by integrated PET/CT in the staging of malignant pleural mesothelioma — G. Genestreti, A. Moretti, et al. (2012)
• Multimodality imaging for characterization, classification, and staging of malignant pleural mesothelioma — L.T. Nickell, J.P. Lichtenberger, et al. (2014)
• North American Multicenter Volumetric CT Study for Clinical Staging of Malignant Pleural Mesothelioma: Feasibility and Logistics of Setting Up a Quantitative Imaging Study — R.R. Gill, D.P. Naidich, et al. (2016)
• Whole-Body MRI: Comparison of Its Capability for TNM Staging of Malignant Pleural Mesothelioma With That of Coregistered PET/MRI, Integrated FDG PET/CT, and Conventional Imaging — Y. Ohno, M. Yui, et al. (2019)
• New Updates of the Imaging Role in Diagnosis, Staging, and Response Treatment of Malignant Pleural Mesothelioma — C. Romei, S.C. Fanni, et al. (2021)
• Diagnostic Laparoscopy Improves Staging of Malignant Pleural Mesothelioma With Routine Positron Emission Tomography Imaging — R.T. Ripley, N. Palivela, et al. (2021)

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