Predicting survival in malignant pleural mesothelioma using routine clinical and laboratory characteristics

Our plain-English summary of Predicting survival in malignant pleural mesothelioma using routine clinical and laboratory characteristics, by S. Gunatilake, D. Lodge, D. Neville, et al (BMJ Open Respiratory Research, 2021).

The study

• Authors: S. Gunatilake, D. Lodge, D. Neville, T. Jones, C. Fogg, P. Bassett, S. Begum, S. Kerley, L. Marshall, S. Glaysher, S. Elliott, R. Stores, L. Bishop, A. Chauhan
• Journal: BMJ Open Respiratory Research
• Published: 2021;8(1)
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Introduction: The prognosis of malignant pleural mesothelioma (MPM) is poor, with a median survival of 8-12 months. The ability to predict prognosis in MPM would help clinicians to make informed decisions regarding treatment and identify appropriate research opportunities for patients. The aims of this study were to examine associations between clinical and pathological information gathered during routine care, and prognosis of patients with MPM, and to develop a 6-month mortality risk prediction model.

Methods: A retrospective cohort study of patients diagnosed with MPM at Queen Alexandra Hospital, Portsmouth, UK between December 2009 and September 2013. Multivariate analysis was performed on routinely available histological, clinical and laboratory data to assess the association between different factors and 6-month survival, with significant associations used to create a model to predict the risk of death within 6 months of diagnosis with MPM.

Results: 100 patients were included in the analysis. Variables significantly associated with patient survival in multivariate analysis were age (HR 1.31, 95% CI 1.09 to 1.56), smoking status (current smoker HR 3.42, 95% CI 1.11 to 4.20), chest pain (HR 2.14, 95% CI 1.23 to 3.72), weight loss (HR 2.13, 95% CI 1.18 to 3.72), platelet count (HR 1.05, 95% CI 1.00 to 1.10), urea (HR 2.73, 95% CI 1.31 to 5.69) and adjusted calcium (HR 1.47, 95% CI 1.10 to 1.94). The resulting risk model had a c-statistic value of 0.76. A Hosmer-Lemeshow test confirmed good calibration of the model against the original dataset.

Conclusion: Risk of death at 6 months in patients with a confirmed diagnosis of MPM can be predicted using variables readily available in clinical practice. The risk prediction model we have developed may be used to influence treatment decisions in patients with MPM. Further validation of the model requires evaluation of its performance on a separate dataset.

© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

In plain English

This retrospective cohort study looked at 100 consecutive patients diagnosed with malignant pleural mesothelioma at Queen Alexandra Hospital, Portsmouth, UK, from December 2009 to September 2013. Portsmouth, the authors note, lies near a dockyard where much asbestos was used. They tested whether routine information at diagnosis was linked to survival and built a model predicting death within 6 months. One-year survival was 26% (95% confidence interval 18% to 35%). A known history of asbestos exposure (69 of 89 patients with data) was not significantly linked to survival. In the final analysis of 74 patients, age, smoking status, chest pain, weight loss, platelet count, urea and adjusted calcium were independently associated with survival. Each 5-year increase in age was associated with a 31% higher risk of death (hazard ratio 1.31, 95% confidence interval 1.09 to 1.56). The authors said the model showed "some ability" to separate low-risk from high-risk patients (c-statistic 0.76), with good agreement between predicted and observed deaths. The authors concluded that routine data can predict 6-month risk of death, but the model needs testing on a separate dataset.

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 using an existing hospital database, with development of a 6-month mortality risk prediction model
• Who was studied: 100 consecutive patients aged over 18 diagnosed with malignant pleural mesothelioma at Queen Alexandra Hospital, Portsmouth, UK, December 2009 to September 2013; 85 men and 15 women; mean age at diagnosis 73.2 years
• Exposure: Not an exposure study. The study examined routine clinical and laboratory factors at diagnosis as predictors of survival. A known history of asbestos exposure was one candidate factor, recorded in 69 of 89 patients (78%). The authors describe Portsmouth as near a dockyard with a large shipbuilding industry where much asbestos was used.
• Main results:
  • One-year survival for the whole cohort of 100 patients was 26% (95% CI 18% to 35%). The authors note this was lower than the national figure of 40%.
  • A known history of asbestos exposure was not significantly associated with survival in the univariate analysis (HR 1.27, 95% CI 0.76 to 2.14, p=0.36; 89 patients with data).
  • The final multivariate model was based on data from 74 patients.
  • After adjustment, each 5-year increase in age was associated with a 31% increase in the risk of death (HR 1.31, 95% CI 1.09 to 1.56).
  • Compared with non-smokers, current smokers had a higher risk of death in the multivariate analysis (HR 3.42, 95% CI 1.11 to 4.20). Ex-smokers had an HR of 2.16.
  • Chest pain at diagnosis was associated with a higher risk of death in the multivariate analysis (HR 2.14, 95% CI 1.23 to 3.72).
  • Weight loss at diagnosis was associated with a higher risk of death in the multivariate analysis (HR 2.13; the results text gives 95% CI 1.18 to 3.72, Table 4 gives 1.18 to 3.86).
  • Higher urea (HR 2.73, 95% CI 1.31 to 5.69, per 5-unit increase) and higher adjusted calcium (HR 1.47, 95% CI 1.10 to 1.94, per 0.1-unit increase) were associated with increased risk in the multivariate analysis. Platelet count also stayed in the model (HR 1.05, 95% CI 1.00 to 1.10).
  • After adjustment, weight, performance status, dyspnoea, haemoglobin, potassium, creatinine and albumin were no longer significantly associated with survival.
  • The model's c-statistic was 0.76, which the authors said suggests some ability to distinguish low-risk from high-risk patients.
  • The Hosmer-Lemeshow test was non-significant (chi-squared 0.8, p=0.38), which the authors interpreted as good agreement between observed and predicted deaths at 6 months. Observed deaths across the three risk groups were 4, 8 and 21, against 3.2, 9.4 and 21.7 predicted.
• The authors' conclusion: The authors concluded that they had developed a model to predict risk of death at 6 months in patients with confirmed malignant pleural mesothelioma, using variables readily available in clinical practice. They said these factors cannot be used alone to predict prognosis, and that the model needs validation on a separate dataset.
• Limitations the authors state:
  • The analysis was done on a retrospective population, which the authors say limits the quality of evidence.
  • Missing data for some variables, such as BMI and pleural fluid results, led to their exclusion from the analysis.
  • Frailer patients with suspected mesothelioma and worse performance status may not have been included in the database. The authors suggest this may explain why performance status was not significant.
  • The small number of women may have influenced the strength of the association with gender.
  • The model has not yet been tested on a separate dataset.

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: Pleural Mesothelioma, Prognosis, Median Survival, Cohort Study, Multivariate Analysis.

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