External validation of prognostic indices for overall survival of malignant pleural mesothelioma

Our plain-English summary of External validation of prognostic indices for overall survival of malignant pleural mesothelioma, by Y. Kataoka, Y. Yamamoto, T. Otsuki, et al (Lung Cancer, 2017).

The study

• Authors: Y. Kataoka, Y. Yamamoto, T. Otsuki, S. Kaku, N. Maehashi-Wada, S. Fukuma, M. Hirabayashi, T. Nakano, S. Fukuhara
• Journal: Lung Cancer
• Published: 2017;113:88-92
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: There are several prognostic indices (PIs) to predict overall survival (OS) in malignant pleural mesothelioma (MPM) patients. Before using a clinical prediction model in the actual clinical setting, empiric evaluation of its performance based on datasets that were not used to develop the model (i.e., external validation) is essential. The purpose of this study was to conduct an external validation of the PIs for MPM.

Materials And Methods: A retrospective cohort study was performed on MPM patients treated at 2 tertiary hospitals in Japan between 2007 and 2015. The primary outcome was OS. Harrell's c-index, and was calculated to examine the discrimination of three models. The bootstrapping technique was used to evaluate optimism.

Results: The participants comprised 183 patients who underwent surgical treatment (n=61), chemotherapy (n=101), and best supportive care (BSC, n=21). The median OS rates were 1014days for surgery, 690days for chemotherapy, and 545days for best supportive care (BSC). The respective discriminations (95% confidence interval) of the Eastern Cooperative Oncology Group Performance Status, the European Organisation for Research and Treatment of Cancer index, regimen, PS, histology or stage (rPHS) index, and Tagawa index for the OS of MPM patients were 0.532 (0.444-0.620), 0.560 (0.472-0.648), 0.584 (0.452-0.716), and 0.525 (0.453-0.596) for surgery; 0.632 (0.539-0.724), 0.622 (0.548-0.696), 0.677 (0.587-0.766), and 0.545 (0.436-0.653) for chemotherapy; and 0.504 (0.365-0.644), 0.583 (0.456--0.710), 0.704 (0.508-0.899), and 0.583 (0.436-0.730) for BSC.

Conclusions: Each PI showed poor discrimination for MPM patients who underwent surgical treatment. The rPHS index showed moderate discrimination for patients given chemotherapy and BSC.

Copyright © 2017 Elsevier B.V. All rights reserved.

In plain English

This retrospective cohort study tested how well existing tools for predicting survival worked for people with malignant pleural mesothelioma (MPM) treated at two tertiary hospitals in the South Hanshin region of Japan. Asbestos exposure was not examined. The 183 patients had surgery (61), chemotherapy (101) or best supportive care (21). Median overall survival was 1014 days after surgery, 690 days with chemotherapy and 545 days with best supportive care. Using Harrell's c-index, the authors compared four tools: ECOG performance status, the EORTC index, the rPHS index (developed earlier by the same research group) and the Tagawa score. For surgery patients, the four c-indices ranged from 0.525 to 0.584. The rPHS index scored 0.677 (95% confidence interval 0.587 to 0.766) for chemotherapy and 0.704 (0.508 to 0.899) for best supportive care. It was consistently better than the other tools, but the differences were not statistically significant. The authors concluded that each tool discriminated poorly for surgery patients and that the rPHS index discriminated moderately for the other two groups. They noted the study may have been too small to detect differences.

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: Retrospective cohort study, based on chart review, that externally validated existing prognostic indices
• Who was studied: 183 patients with histologically proven malignant pleural mesothelioma at 2 tertiary hospitals in the South Hanshin medical region of Japan. Chemotherapy and best supportive care patients were treated April 2013 to March 2015, and surgical patients April 2007 to March 2015. Groups: surgery n = 61, chemotherapy n = 101, best supportive care n = 21.
• Exposure: Asbestos exposure was not studied. The study evaluated four prognostic tools for overall survival: Eastern Cooperative Oncology Group Performance Status (PS), the EORTC index, the rPHS (regimen, PS, histology or stage) index and the Tagawa score. The rPHS index had been developed previously by the same group.
• Main results:
  • Median overall survival was 1014 days in the surgery group, 690 days in the chemotherapy group and 545 days in the best supportive care group.
  • Surgery group (N = 61), c-index (95% confidence interval): PS 0.532 (0.444 to 0.620), EORTC 0.560 (0.472 to 0.648), rPHS 0.584 (0.452 to 0.716), Tagawa 0.525 (0.453 to 0.596). The authors described every index as showing poor discrimination for surgery.
  • Chemotherapy group (N = 101), c-index (95% confidence interval): PS 0.632 (0.539 to 0.724), EORTC 0.622 (0.548 to 0.696), rPHS 0.677 (0.587 to 0.766), Tagawa 0.545 (0.436 to 0.653).
  • Best supportive care group (N = 21), c-index (95% confidence interval): PS 0.504 (0.365 to 0.644), EORTC 0.583 (0.456 to 0.710), rPHS 0.704 (0.508 to 0.899), Tagawa 0.583 (0.436 to 0.730).
  • The rPHS index discriminated consistently better than the other indices, but the differences were not statistically significant.
  • In the calibration analysis, the survival curves for each treatment group showed good agreement between observed and predicted survival.
• The authors' conclusion: The authors concluded that each prognostic index showed poor discrimination for MPM patients treated with surgery, and that the rPHS index showed moderate discrimination for patients given chemotherapy or best supportive care. They added that further updating is needed for individual prediction.
• Limitations the authors state:
  • Discrimination was poor for surgical patients. The indices do not include prognostic factors such as co-morbidities, post-operative complications and tumor volume before chemotherapy.
  • The rPHS index showed only moderate discrimination for chemotherapy and best supportive care patients.
  • Because of the small sample size, the study may have been underpowered to detect differences between the indices.
  • Because the design was retrospective, there were no detailed pre-existing symptom data, so the CALGB prognostic index could not be compared.

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: Overall Survival, Pleural Mesothelioma, Cohort Study, Chemotherapy, confidence interval, Performance Status, Histology.

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• Prognostic factors for progression-free and overall survival in malignant pleural mesothelioma — J. Guzmán-Casta, S. Carrasco-CaraChards, et al. (2021)
• Validation of Progression-Free Survival as a Surrogate Endpoint for Overall Survival in Malignant Mesothelioma: Analysis of Cancer and Leukemia Group B and North Central Cancer Treatment Group (Alliance) Trials — X. Wang, X. Wang, et al. (2017)
• Survival and prognostic factors in malignant pleural mesothelioma: a retrospective study of 314 patients in the west part of Japan — S. Nojiri, K. Gemba, et al. (2011)
• Validation of prognostic factors in malignant pleural mesothelioma: a retrospective analysis of data from patients seeking compensation from the New South Wales Dust Diseases Board — S.C. Kao, J. Vardy, et al. (2013)

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