Reflecting real-world patients with mesothelioma in research: an interim report of baseline characteristics from the ASSESS-meso cohort

Our plain-English summary of Reflecting real-world patients with mesothelioma in research: an interim report of baseline characteristics from the ASSESS-meso cohort, by R.J.H. Conway, N. Smith, W. Cooper, et al (ERJ Open Research, 2023).

The study

• Authors: R.J.H. Conway, N. Smith, W. Cooper, G. Lynch, S. Patole, J. Symonds, A. Edey, N.A. Maskell, A.C. Bibby, ASSESS-meso Collaborative group 4, ASSESS-meso Collaborative group
• Journal: ERJ Open Research
• Published: 2023;9(6)
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objective: Mesothelioma varies in clinical phenotype and survival. Clinical trials are unavoidably affected by selection bias, reducing generalisability. ASSESS-meso is a UK, multicentre, prospective, mesothelioma cohort study (ISRCTN61861764). This pre-specified interim analysis, conducted when recruitment reached 25% of target, summarised participant characteristics and evaluated external validity through comparison with real-world and clinical trial cohorts.

Methods: The study took place at 14 hospitals across the UK. People diagnosed with mesothelioma, at any anatomical site, were eligible. Clinical, radiological and biochemical data were collected at enrolment. In this interim report, the external validity of the cohort was investigated through comparison of baseline demographic data with populations included in the 2020 UK National Mesothelioma Audit (real-world cohort), and CHECKMATE-743 and MAPS trials (clinical trial cohorts).

Results: 244 patients were enrolled between 7 April 2017 and 1 March 2022. The cohort was predominantly male (195 out of 244; 80%) with a median age of 74 years. Pleural disease and epithelioid subtypes were most prevalent. ASSESS-meso participants were more similar to the real-world population with regard to age, performance status, disease site and stage than the clinical trial population. ASSESS-meso participants were more likely to be formally staged and less likely to have undifferentiated histology compared with the real-world cohort, possibly reflecting high rates of discussion of ASSESS-meso participants at regional mesothelioma multidisciplinary team meetings. As expected, poorer performance status, non-epithelioid histology and neutrophil-lymphocyte ratio were associated with shorter survival in the adjusted analysis.

Conclusion: ASSESS-meso is representative of the UK mesothelioma population. Future outputs from the cohort will help characterise different mesothelioma phenotypes with high external validity.

Copyright ©The authors 2023.

In plain English

This interim report came from ASSESS-meso, an ongoing prospective cohort study of people with mesothelioma at 14 UK hospitals. The analysis, planned for when recruitment reached 25% of target, covered 244 patients enrolled by 1 March 2022. The authors compared them with the 2020 UK National Mesothelioma Audit and two clinical trials, MAPS and CHECKMATE-743. Most participants were male (195, 79.9%), the median age was 74 years, and 233 (95.5%) had pleural disease. Asbestos exposure was recalled by 205 (84.0%), and 112 (45.9%) described direct exposure from working with asbestos. Of the 49 women, 18 recalled no exposure. The article did not name asbestos fiber types. After adjustment, shorter survival was associated with performance status of 2 or higher, non-epithelioid tumour type, and a higher neutrophil–lymphocyte ratio. The cohort resembled the national audit in age, sex and disease site, while the trial populations tended to be younger. The authors concluded that the cohort was representative of UK mesothelioma patients. They noted it was not powered for a fully adjusted survival model and had missing data, partly due to COVID-19.

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: Pre-specified interim analysis of an ongoing multicentre, prospective, longitudinal, observational cohort study, with comparison against a national audit and two clinical trial populations
• Who was studied: 244 adults with a multidisciplinary-team-confirmed diagnosis of mesothelioma (any disease site), recruited at 14 UK hospitals (12 in England, one in Scotland, one in Wales) and enrolled within 12 weeks of diagnosis. Enrolment ran from 4 July 2017 to the data extraction date of 1 March 2022.
• Exposure: Participant-recalled asbestos exposure, grouped as direct (112, 45.9%), indirect (57, 23.4%), environmental (36, 14.8%) or none recalled (37, 15.2%). No fiber types, products or doses were reported.
• Main results:
  • Most participants were male (195 of 244, 79.9%) and over age 65 (219, 89.8%). The median age was 74.0 years (range 53 to 88).
  • The pleura was the most common disease site (233 of 244, 95.5%).
  • Epithelioid mesothelioma was the most frequent histological subtype (163 of 244, 66.8%).
  • Among the 49 women, 18 (36.7%) recalled no asbestos exposure. Of the 31 who did recall exposure, 17 (54.8%) reported passive exposure from spending time in an enclosed space where others worked with asbestos.
  • Median survival for the cohort was 313.5 days (IQR 162 to 488).
  • In the adjusted model, a performance status of 2 or higher was associated with shorter survival (adjusted HR 3.96, 95% CI 2.14 to 7.30, p less than 0.001). Non-epithelioid histology was also associated with shorter survival (adjusted HR 1.83, 95% CI 1.01 to 3.31, p=0.045).
  • In the adjusted model, a higher absolute neutrophil–lymphocyte ratio was associated with shorter survival (adjusted HR 1.07, 95% CI 1.03 to 1.11, p=0.001).
  • Neither sex nor disease site was associated with a survival difference.
  • Among the 192 participants for whom a Brims score could be calculated, a higher Brims prognostic group was associated with increased mortality risk (adjusted HR 2.05, 95% CI 1.55 to 2.72, p less than 0.001).
  • ASSESS-meso participants were similar to the UK National Mesothelioma Audit population in age, sex and disease site. The clinical trial populations tended to be younger and to include a higher proportion of women.
  • Unstaged disease was less common in ASSESS-meso (17%) than in the national audit dataset (34%).
• The authors' conclusion: The authors concluded that ASSESS-meso had enrolled a representative cohort of mesothelioma patients, and that future outputs would have high external validity for the UK mesothelioma population.
• Limitations the authors state:
  • This was an interim analysis and was not formally powered for a fully adjusted survival model. The authors gave this as the likely reason that known factors such as age and stage were not significant in the adjusted analysis.
  • Data were missing, particularly for performance status and smoking status.
  • The cohort was immature: more than half of participants were still alive at the time of analysis.
  • 17% of participants had no recorded stage.
  • The COVID-19 pandemic affected data collection and recruitment.
  • ASSESS-meso included fewer people with performance status 3 to 4 than the national audit. The authors suggested this may reflect a lower likelihood of hospital-based follow-up in this group.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Clinical Trial, Selection Bias, Cohort Study, Epithelioid, Performance Status, Histology, Multidisciplinary Team.

Related studies

• Protocol for a prospective observational cohort study collecting data on demographics, symptoms and biomarkers in people with mesothelioma (ASSESS-meso) — R.J.H. Conway, J. Symonds, et al. (2022)
• I-O Optimise: a novel multinational real-world research platform in thoracic malignancies — S. Ekman, F. Griesinger, et al. (2019)
• Advancing real-world research in thoracic malignancies: learnings from the international I-O Optimise initiative — S.P. Johnsen, P. Baas, et al. (2025)
• The CARET asbestos-exposed cohort: baseline characteristics and comparison to other asbestos-exposed cohorts — S. Barnhart, J. Keogh, et al. (1997)
• Efficacy of chemotherapy for malignant pleural mesothelioma according to histology in a real-world cohort — S. Cedres, J.D. Assaf, et al. (2021)
• Follow-up after first-Line nivOlumab plus ipilimumab in patients with diffuse pleuRal mesotheliomA: a real-world Dutch cohort study-FLORA — L.H. Douma, M.M. Hofman, et al. (2025)

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