Patient characteristics, treatment patterns, and survival outcomes for patients with malignant pleural mesothelioma in Denmark between 2011 and 2018: a nationwide population-based cohort study

Our plain-English summary of Patient characteristics, treatment patterns, and survival outcomes for patients with malignant pleural mesothelioma in Denmark between 2011 and 2018: a nationwide population-based cohort study, by J.B. Sørensen, P. Baas, S.K. Szépligeti, et al (Acta Oncologica, 2024).

The study

• Authors: J.B. Sørensen, P. Baas, S.K. Szépligeti, A.B. Pedersen, S.P. Johnsen, R. Carroll, M.J. Schoemaker, C. Rault, M.J. Daumont, V. Ehrenstein
• Journal: Acta Oncologica
• Published: 2024;63:649-657
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Malignant pleural mesothelioma (MPM) is a rare thoracic malignancy with poor prognosis and limited treatment options. Immunotherapy shows potential for improved outcomes; however, real-world evidence on its use will take time to accumulate. This study examined patient characteristics, treatment patterns, overall survival (OS), and predictors of mortality among patients diagnosed with MPM in Denmark prior to the introduction of newer treatments.

Methods: This historical cohort study based on routinely collected Danish National Registry data included adults newly diagnosed with MPM between 01 January 2011 and 31 May 2018. Summary statistics were used to describe patient characteristics and initial treatment. OS was estimated using Kaplan-Meier methods; Cox regression was used to compare patient mortality against the (age/sex-matched) general population and to investigate mortality predictors.

Results: Overall, 880 patients were included; 44% had advanced MPM, 37% had non-advanced MPM, and 19% had unknown MPM stage. Median age at diagnosis was 71.9 years, and 82% of the patients were male. Within 180 days of diagnosis, no treatment was recorded for 215 patients (54%) with advanced MPM and 150 (46%) with non-advanced MPM. Median time-to-initial treatment (interquartile range) was 47 days (31-111) overall, 40 days (28-77) in patients with advanced MPM, and 53 days (35-121) with non-advanced MPM. Median OS was 13.7 months overall (non-advanced MPM: 18.0 months vs. advanced MPM: 10.0 months). Predictors of higher mortality were older age at diagnosis, histology, and advanced MPM stage.

Interpretation: These findings provide a baseline upon which to evaluate MPM epidemiology as newer treatments are adopted in routine practice.

In plain English

This Danish nationwide registry study included 880 adults diagnosed with malignant pleural mesothelioma from January 2011 to May 2018, before newer immunotherapy drugs were routinely used. It had no occupation data, so asbestos exposure was not examined. Most patients (82%) were male, and the median age at diagnosis was 71.9 years. Patients were grouped by both tumour stage and tumour type; 44% were in the advanced group. Within 180 days of diagnosis, none of the study's listed treatments was recorded for 54% of the advanced group and 46% of the non-advanced group. Median survival was 13.7 months overall (95% confidence interval 12.6 to 14.6), 18.0 months in the non-advanced group and 10.0 months (95% CI 8.8 to 11.9) in the advanced group. An estimated 6.9% (95% CI 4.9 to 9.4) were alive at 5 years. Risk of death was higher at age 75 or older than under 65, with sarcomatoid or unspecified than epithelioid tumour types, and in stage IV disease. The authors concluded the findings provide a baseline for judging newer treatments. They noted that treatment records may be incomplete and that stage and tumour-type data were often missing.

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: Historical, nationwide, population-based cohort study using linked Danish national registries (Civil Registration System, Cancer Registry, National Registry of Patients)
• Who was studied: 880 adults (aged 18 or over) in Denmark newly diagnosed with malignant pleural mesothelioma between 1 January 2011 and 31 May 2018, followed until 31 December 2018. Patients were placed in three study-defined groups based on both stage and histology: 325 non-advanced, 390 advanced and 165 unknown stage. 82% (n = 720) were male and the median age was 71.9 years. Counts were rounded to the nearest 5 under Danish privacy rules.
• Exposure: Asbestos exposure was not studied. The study had no data on occupation or smoking. It examined initial treatments recorded within 180 days of diagnosis (systemic anticancer therapy, radiotherapy, surgery).
• Main results:
  • Overall median survival was 13.7 months (95% CI 12.6 to 14.6) for all patients with malignant pleural mesothelioma.
  • Overall survival probability was 55.2% (95% CI 51.8 to 58.4) at 1 year and 6.9% (95% CI 4.9 to 9.4) at 5 years.
  • Median survival was 18.0 months in the non-advanced MPM group and 10.0 months in the advanced MPM group.
  • Median survival in the advanced MPM group was 10.0 months (95% CI 8.8 to 11.9).
  • Within 180 days of diagnosis, no treatment was recorded for 215 patients (54%) in the advanced MPM group and 150 (46%) in the non-advanced MPM group.
  • In the overall population, systemic anticancer therapy was recorded in 31% (n = 275), radiotherapy in 11% (n = 95) and surgery in 15% (n = 135).
  • Patients aged 75 years and above at diagnosis had higher mortality than patients under 65 years (adjusted hazard ratio 2.0, 95% CI 1.6 to 2.4).
  • Compared with epithelioid histology, mortality was higher with sarcomatoid histology (adjusted hazard ratio 2.3, 95% CI 1.7 to 3.0) and with unspecified histology (adjusted hazard ratio 2.2, 95% CI 1.8 to 2.7).
  • TNM stage IV was associated with higher mortality than stage IA, the reference group (adjusted hazard ratio 2.1, 95% CI 1.5 to 2.8).
  • A medium or high comorbidity score did not appear to affect mortality risk compared with a low score.
• The authors' conclusion: The authors concluded that a diagnosis of malignant pleural mesothelioma was associated with high mortality among all patients, consistent with data from other European countries. They stated that the results provide a baseline for evaluating the impact of newer treatments.
• Limitations the authors state:
  • The algorithm used to define initial treatment was not validated in the Danish setting, so initial treatment status may be misclassified.
  • Completeness of recorded therapy was not assessed, so the proportion of treated patients may be underestimated.
  • There were no data on occupation or smoking status.
  • A high proportion of data on stage and histology was missing.
  • Biphasic mesothelioma was placed in the advanced prognosis group even though current staging does not classify it as advanced. The authors stated that this may alter survival results for the subgroups.

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, Cohort Study, Prognosis, Immunotherapy, Overall Survival, Histology, Epidemiology.

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