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

Our plain-English summary of 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, by S.C. Kao, J. Vardy, M. Chatfield, et al (Clinical Lung Cancer, 2013).

The study

• Authors: S.C. Kao, J. Vardy, M. Chatfield, P. Corte, N. Pavlakis, C. Clarke, N. van Zandwijk, S. Clarke
• Journal: Clinical Lung Cancer
• Published: 2013;14(1):70-7
• Cited by: 48 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: We aimed to examine the prognostic values of established risk factors and to validate the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) in an independent series of patients with malignant pleural mesothelioma (MPM).

Patients And Methods: A total of 148 patients who applied for compensation at the Dust Diseases Board from 2007 to 2009 were included in this study. Overall survival was determined by the Kaplan-Meier method, and NLR was defined as the absolute neutrophil divided by the lymphocyte count. The prognostic value of the variables was examined by using Cox regression analysis, and all factors were entered into a multivariate model to determine their independent effect.

Results: The patient characteristics were median age of 73 years; 93% men; 59% epithelial subtype; median NLR of 3.5 at diagnosis (n = 79); median overall survival of 10.6 months. The following variables were predictive of longer overall survival in univariate analysis: younger age, epithelial subtype, lower tumor stage, low white cell count, low platelet count, low hemoglobin level, and low NLR. Multivariate analysis confirmed that nonepithelial vs. epithelial subtype (hazard ratio [HR], 3.0; P < .001), tumor stage (HR, 1.6; P < .001), hemoglobin level difference ≥10 vs. <10 (HR, 2.0; P = .03), no chemotherapy vs. use of chemotherapy (HR, 2.4; P < .001), and NLR ≥3 vs. <3 (HR, 2.2; P < .01) were independently associated with prognosis.

Conclusions: Apart from previously recognized factors, such as histosubtype, tumor stage, and hemoglobin level difference, NLR, an index of systemic inflammation bears prognostic significance that shows that a snapshot of immune status is able to convey important prognostic information.

Copyright © 2013 Elsevier Inc. All rights reserved.

In plain English

This retrospective study looked at 148 people with malignant pleural mesothelioma compensated by the New South Wales Dust Diseases Board, Australia, from March 2007 to March 2009. The authors tested which factors were linked to survival, including a blood inflammation marker, the neutrophil-to-lymphocyte ratio (NLR). Asbestos exposure was not among the factors analyzed. Median survival overall was 10.6 months (95% confidence interval 8.2 to 13). In a combined analysis of 130 patients, shorter survival was independently linked with five factors: non-epithelial tumor type (hazard ratio 3.0), each one-step rise in stage (1.6), hemoglobin 10 g/L or more below 160 g/L for men or 140 g/L for women (2.0), no chemotherapy (2.4), and NLR of 3 or more (2.2). Among the 79 patients with NLR results, median survival was 16.9 months (95% CI 12.3 to 21.6) with NLR under 3. It was 8.0 months (5.8 to 10.3) with NLR of 3 or more. The authors concluded that NLR carries prognostic information alongside known factors. They noted three limits: performance status was unrecorded, chemotherapy was not randomized, and requiring documented work exposure may have biased inclusion.

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 review of compensation records (survival analysis using Kaplan-Meier and Cox regression)
• Who was studied: 148 patients with malignant pleural mesothelioma who received compensation from the New South Wales Dust Diseases Board, Australia, and agreed to take part, March 2007 to March 2009. Of 264 applicants invited, 13 with peritoneal mesothelioma and 11 already included in the authors' earlier studies were excluded. Median age was 73 years (range 45-91); 137 were men and 11 were women.
• Exposure: Asbestos exposure was not analyzed as a prognostic factor, and fiber types were not reported. The factors examined were clinical and blood-test measures: age, sex, tumor subtype, clinical stage, symptom duration, hemoglobin level difference, platelet count, white cell count and neutrophil-to-lymphocyte ratio at diagnosis. Eligibility for compensation required documented occupational exposure.
• Main results:
  • Median overall survival for all 148 patients was 10.6 months (95% CI 8.2 to 13). By the censor date (March 31, 2011), 139 patients had died.
  • In the multivariate analysis (130 patients, 122 deaths), non-epithelial versus epithelial subtype was associated with shorter survival (hazard ratio 3.0).
  • In the multivariate analysis, tumor stage (entered as a continuous variable) had a hazard ratio of 1.6 per one-unit increase in stage.
  • In the multivariate analysis, a hemoglobin level difference of 10 g/L or more versus less than 10 had a hazard ratio of 2.0. The difference was measured relative to 160 g/L in men and 140 g/L in women.
  • In the multivariate analysis, no chemotherapy versus chemotherapy was associated with shorter survival (hazard ratio 2.4), and an NLR of 3 or more versus less than 3 had a hazard ratio of 2.2.
  • The multivariate analysis included 130 patients, with 122 deaths.
  • Median survival was 13.5 months for patients with the epithelial subtype and 4.5 months for those with non-epithelial subtypes.
  • Among the 79 patients with NLR results, median survival was 16.9 months (95% CI 12.3 to 21.6) for those with NLR below 3. It was 8.0 months (95% CI 5.8 to 10.3) for those with NLR of 3 or more.
  • Median NLR rose with tumor stage: 2.8 for stage I, 3.3 for stage II, 3.5 for stage III and 3.7 for stage IV.
• The authors' conclusion: The authors concluded that histologic subtype, tumor stage and hemoglobin level difference were confirmed as prognostic factors. They also concluded that NLR, an index of systemic inflammation, carries prognostic significance, and that the right NLR cut-off should be studied prospectively.
• Limitations the authors state:
  • Because the study was retrospective, performance status (how well patients could carry out daily activities) could not be collected.
  • NLR results were available for only about half of the patients.
  • Patients needed documented occupational exposure to qualify for compensation, which may have caused selection bias. One sign of this is that more of the study patients were men (92%) than the national rate of 84% in 2007.
  • Chemotherapy was not randomly assigned, so its link with survival is subject to selection bias.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Overall Survival, Median Overall Survival, Multivariate Analysis, Hazard Ratio, Chemotherapy, Prognosis, Inflammation.

Related studies

• Patterns of care for malignant pleural mesothelioma patients compensated by the Dust Diseases Board in New South Wales, Australia — S.C. Kao, S. Clarke, et al. (2013)
• Factors associated with survival in a large series of patients with malignant pleural mesothelioma in New South Wales — A. Linton, N. Pavlakis, et al. (2014)
• Low calretinin expression and high neutrophil-to-lymphocyte ratio are poor prognostic factors in patients with malignant mesothelioma undergoing extrapleural pneumonectomy — S.C. Kao, S. Klebe, et al. (2011)
• Geographic and socioeconomic factors in patients with malignant pleural mesothelioma in New South Wales and their impact upon clinical outcomes — A. Linton, M. Soeberg, 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)
• Compensation scheme for complementary and alternative medicine use in asbestos-related diseases in New South Wales, Australia — C. Oak, H.J. Choi, et al. (2012)

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