Response evaluation in mesothelioma: Beyond RECIST

Our plain-English summary of Response evaluation in mesothelioma: Beyond RECIST, by L. Cheng, N. Tunariu, D.J. Collins, et al (Lung Cancer, 2015).

The study

• Authors: L. Cheng, N. Tunariu, D.J. Collins, M.D. Blackledge, A.M. Riddell, M.O. Leach, S. Popat, D.M. Koh
• Journal: Lung Cancer
• Published: 2015;90(3):433-41
• Type of article: Review
• Cited by: 22 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant pleural mesothelioma (MPM) typically demonstrates a non-spherical growth pattern, so it is often difficult to accurately categorize change in tumour burden using size-based tumour response criteria (e.g., WHO (World Health Organisation), RECIST (Response Evaluation Criteria in Solid Tumours) and modified RECIST). Functional imaging techniques are applied to derive quantitative measurements of tumours, which reflect particular aspects of the tumour pathophysiology. By quantifying how these measurements change with treatment, it is possible to observe treatment effects. In this review, we survey the existing roles of CT and MRI for the management of MPM, including the currently applied size measurement criteria for the assessment of treatment response. New functional imaging techniques, such as positron emission tomography (PET), diffusion-weighted MRI (DWI) and dynamic contrast-enhanced MRI (DCE-MRI) that may potentially improve the assessment of treatment response will be highlighted and discussed.

Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

In plain English

This article reviewed published research on imaging used to judge whether malignant pleural mesothelioma is responding to treatment. It did not study asbestos exposure. The authors explained that this cancer grows in sheets rather than round lumps, making changes hard to judge accurately with size-based rules (WHO, RECIST and modified RECIST, which was adapted for mesothelioma), though careful measurements can still give meaningful results about patient outcomes. They summarized other researchers' studies of CT and MRI volume measurement, FDG-PET, diffusion-weighted MRI and dynamic contrast-enhanced MRI. One cited pooled analysis of 716 patients from nine trials found significantly longer survival in patients with partial response (median 12.8 months) or stable disease (9.4 months) after chemotherapy than in those whose disease progressed (3.4 months). The review described the PET evidence on treatment response as uneven. It noted that no published trials had yet tested diffusion-weighted MRI for treatment response in this disease. The authors concluded that diffusion-weighted MRI appeared the most promising MRI technique, and called for standardized methods and collaborative multi-centre studies.

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: Narrative review of published imaging studies
• Who was studied: Published literature on CT, MRI and functional imaging (PET, diffusion-weighted MRI, dynamic contrast-enhanced MRI) in malignant pleural mesothelioma. The authors were based at UK institutions. The article does not describe how studies were searched for or selected.
• Exposure: No asbestos exposure was studied. The article only mentions in its introduction that malignant pleural mesothelioma is related to asbestos exposure. No fiber types are named. The review's subject was imaging methods for measuring treatment response.
• Main results:
  • The authors explained that the cancer grows along the pleural surface in sheets rather than as spherical lesions.
  • The authors explained that conventional size measurements assume spherical tumour growth, and that this assumption cannot be meaningfully applied to malignant pleural mesothelioma.
  • The modified RECIST criteria were proposed specifically for malignant pleural mesothelioma in 2004.
  • The authors stated that size measurements, when performed meticulously, can yield meaningful results about patient outcomes. They added that modified RECIST is associated with lower variability between studies and between observers.
  • A cited modeling study found that, in a mesothelioma model, RECIST classified partial response on a 30% volume decrease and progressive disease on a 20% volume increase.
  • A cited pooled analysis of 716 patients from nine clinical trials found that patients with partial response (median survival 12.8 months) or stable disease (9.4 months) after chemotherapy had significantly longer overall survival than patients with disease progression (3.4 months).
  • In a cited study of 23 patients, a decrease in total glycolytic volume on PET after one cycle of chemotherapy was statistically significantly correlated with improved survival (P = 0.015).
  • In another cited study of patients treated with pemetrexed and platinum-based chemotherapy, changes in SUVmax on PET did not predict overall survival.
  • In a cited dynamic contrast-enhanced MRI study, clinical non-responders (median survival 460 days) had significantly higher Kep values (3.6 min) than responders (2.6 min, median survival 780 days).
• The authors' conclusion: The authors concluded that, of the available MRI techniques, diffusion-weighted MRI appeared most promising, because it is relatively quick to perform and needs no contrast agent.
• Limitations the authors state:
  • The authors noted that no published trials had evaluated diffusion-weighted MRI or ADC for treatment response assessment in this disease.
  • The authors described the evidence for PET in assessing treatment response as uneven.
  • The authors noted that the dynamic contrast-enhanced MRI finding needs further validation because the study sample was small.
  • The authors stated that functional MRI methods need standardization and collaborative multi-centre studies.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Pleural Mesothelioma, Modified RECIST (mRECIST), Diffusion-Weighted MRI.

Related studies

• Metabolic response assessment with 18F-FDG-PET/CT is superior to modified RECIST for the evaluation of response to platinum-based doublet chemotherapy in malignant pleural mesothelioma — S. Kanemura, K. Kuribayashi, et al. (2017)
• Revised Modified Response Evaluation Criteria in Solid Tumors for Assessment of Response in Malignant Pleural Mesothelioma (Version 1.1) — S.G. Armato, A.K. Nowak (2018)
• Three-dimensional evaluation of chemotherapy response in malignant pleural mesothelioma — G. Ak, M. Metintas, et al. (2010)
• Malignant Mesothelioma of the Tunica Vaginalis Testis: Outcomes Following Surgical Management Beyond Radical Orchiectomy — P. Recabal, B. Rosenzweig, et al. (2017)
• Focal pleural tumorlike conditions: nodules and masses beyond mesotheliomas and metastasis — M.C. de Paula, D.L. Escuissato, et al. (2015)
• Malignant pleural mesothelioma: role of CT, MRI, and PET/CT in staging evaluation and treatment considerations — M.T. Truong, C. Viswanathan, et al. (2013)

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