Three-dimensional evaluation of chemotherapy response in malignant pleural mesothelioma

Our plain-English summary of Three-dimensional evaluation of chemotherapy response in malignant pleural mesothelioma, by G. Ak, M. Metintas, S. Metintas, et al (European Journal of Radiology, 2010).

The study

• Authors: G. Ak, M. Metintas, S. Metintas, H. Yildirim, R. Ozkan, H. Ozden
• Journal: European Journal of Radiology
• Published: 2010;74(1):130-5
• Cited by: 27 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: Measurement of tumor response to chemotherapy in malignant pleural mesothelioma (MPM) is problematic because of non-spherical tumor growth patterns and difficulty in choosing target lesion. In this study, we aimed to determine the effectiveness of tumor volume measurement for evaluating chemotherapy response.

Methods: Fifty-seven MPM patients were included. Chemotherapy responses were evaluated by computed tomography (CT) using volumetric method, World Health Organization (WHO), and modified Response Evaluation Criteria in Solid Tumor (RECIST). The tumor volume was measured using the Cavalieri principle of stereological approaches.

Results: According to the volumetric method, median survival was 10.0 months for progressive disease (PD), 14.0 months for stable disease (SD) and 16.0 months for objective response (OR). According to the WHO method, median survival was 11.3, 14.0, and 13.0 months, respectively. For modified RECIST, median survival was 10.0, 14.0, and 14.0 months, respectively. The correspondence between the WHO and modified RECIST methods was substantial (K=0.66), as was that between the volumetric and WHO methods (K=0.64); however the correspondence between the volumetric and modified RECIST methods was only moderate (K=0.52).

Conclusions: The most suitable chemotherapy response measurement technique is the volumetric method because of non-spherical tumor growth patterns in MPM. However, larger studies should be performed to better establish the suitability of this method. We recommend our method for determining the chemotherapy response in mesothelioma cases. However, modified RECIST criteria can also be applied due to favourable prediction of survival, ease of application, and moderate correspondence with the volumetric method.

Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

In plain English

This study compared three CT-based ways of judging whether malignant pleural mesothelioma responded to chemotherapy; it did not study asbestos exposure. Fifty-seven consecutive patients were scanned before and after two or three chemotherapy cycles, and tumors were measured by World Health Organization (WHO) two-dimensional, modified RECIST one-dimensional, and three-dimensional volume methods. Median survival, with 95% confidence intervals, for progressing, stable and responding patients was: by volume, 10.0 (7.6 to 12.4), 14.0 (10.736 to 17.264) and 16.0 (6.298 to 25.702) months; by WHO, 11.3 (8.427 to 14.173), 14.0 (5.598 to 22.402) and 13.0 (5.447 to 20.553); by modified RECIST, 10.0 (3.459 to 16.541), 14.0 (9.734 to 18.266) and 14.0 (7.763 to 20.237). With all three methods, stable and responding patients lived longer than progressing patients, but the stable-versus-responding difference was not statistically significant. Agreement was substantial between WHO and modified RECIST and between volume and WHO, but moderate between volume and modified RECIST. The authors recommended the volume method, said modified RECIST could also be used, and called for larger studies, citing few patients and time-consuming manual measurement.

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: Clinical imaging study comparing three CT-based methods (WHO bi-dimensional, modified RECIST uni-dimensional, and a volumetric method using the Cavalieri principle) for measuring chemotherapy response, with survival compared across response groups
• Who was studied: 57 consecutive patients with histologically confirmed malignant pleural mesothelioma (mean age 59.2 years; 31 men, 26 women; 43 epithelial type). Patients who received other therapy in addition to chemotherapy were excluded. The authors are at Eskisehir Osmangazi University, Turkey. Study dates are not stated.
• Exposure: Not an asbestos exposure study (asbestos is mentioned only as background in the introduction). The patients received chemotherapy; the drugs used are not named.
• Main results:
  • Median survival by volumetric method: 10.0 months (95% CI 7.6 to 12.4) for progressive disease, 14.0 months (10.736 to 17.264) for stable disease, 16.0 months (6.298 to 25.702) for objective response (log-rank p = 0.008)
  • Median survival by WHO criteria: 11.3 months (95% CI 8.427 to 14.173) for progressive disease, 14.0 (5.598 to 22.402) for stable disease, 13.0 (5.447 to 20.553) for objective response (log-rank p = 0.010)
  • Median survival by modified RECIST: 10.0 months (95% CI 3.459 to 16.541) for progressive disease, 14.0 (9.734 to 18.266) for stable disease, 14.0 (7.763 to 20.237) for objective response (log-rank p = 0.006)
  • For all three methods, patients with stable disease and objective response had longer median survival than patients with progressive disease
  • Survival did not differ significantly between stable disease and objective response (p = 0.283 WHO; p = 0.476 modified RECIST; p = 0.071 volumetric method)
  • Agreement was substantial between WHO and modified RECIST (K = 0.66) and between volumetric and WHO methods (K = 0.64)
  • Agreement between the volumetric method and modified RECIST was moderate (K = 0.52)
  • Response rates (progressive / stable / objective response, n of 57): WHO 22 (38.6%) / 24 (42.1%) / 11 (19.3%); modified RECIST 20 (35.1%) / 19 (33.3%) / 18 (31.6%); volumetric 24 (42.1%) / 25 (43.9%) / 8 (14.0%)
  • Volumetric thresholds set by ROC analysis: partial response was a total tumor volume decrease of at least 50%; progressive disease was an increase of 15% or more
• The authors' conclusion: The authors concluded that the volumetric method is the most suitable because of the tumor's non-spherical growth, recommended it, said modified RECIST criteria can also be applied, and said larger studies are needed
• Limitations the authors state:
  • Tumor volume was measured manually from CT films on a light box, which is time-consuming
  • The number of patients was small, making it difficult to set volumetric response criteria
  • Patients who had talc pleurodesis were not assessed separately
  • Inter-observer variability was not evaluated

Topics

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

Medical terms in this study, explained in our Lexicon: Chemotherapy, Pleural Mesothelioma, Median Survival, Modified RECIST (mRECIST), Mesothelioma.

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