Malignant pleural mesothelioma in Finland: regional and gender variation

Our plain-English summary of Malignant pleural mesothelioma in Finland: regional and gender variation, by S. Laaksonen, I. Ilonen, E. Kuosma, et al (Acta Oncologica, 2019).

The study

• Authors: S. Laaksonen, I. Ilonen, E. Kuosma, E. Sutinen, H. Wolff, T. Vehmas, K. Husgafvel-Pursiainen, J.A. Salo, K. Koli, J. Räsänen, M. Myllärniemi
• Journal: Acta Oncologica
• Published: 2019;58(1):38-44
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Malignant pleural mesothelioma (MPM) is a rare occupational cancer with a poor prognosis. Even with a multimodality treatment approach, the treatment outcomes remain unsatisfactory. The use of asbestos has been banned in most developed countries, but MPM continues to be a significant occupational disease also in these countries. Aim of this study is to identify modern epidemiology and assess equality in care.

Methods: Our study cohort consists of 1010 patients diagnosed with MPM in Finland during 2000-2012. The data were collected from the Finnish Cancer Registry, the National Workers' Compensation Center Registry and the National Registry of Causes of Death, Statistics Finland.

Results: Women were diagnosed a mean of 4.5 years later than males (p = .001), but survival did not differ (overall median survival 9.7 months). A workers' compensation claim was more common in males (OR 11.0 [95% CI 7.5-16.2]) and in regions with a major asbestos industry (OR 1.7 [95% CI 1.3-2.2]). One-year and three-year survivals did not differ regionally. Patients without chemotherapy treatment had an inferior survival (RR 1.8 [95% CI 1.5-2.0]). The initial survival benefit gained with pemetrexed was diluted at 51 months.

Conclusions: MPM is a disease with a poor prognosis, although chemotherapy appears to improve survival time. Significant gender and regional variation exists among patients, with notable differences in diagnostic and treatment practices. Long-term outcomes with pemetrexed remain indeterminate.

Impact: Emphasize centralized consult services for the diagnosis, treatment and support that patients receive for MPM, facilitating equal outcomes and compensation.

In plain English

This study used national registry data on 1,010 patients diagnosed with malignant pleural mesothelioma in Finland in 2000–2012 (801 men, 209 women). Women were older at diagnosis than men (mean 72.6 versus 68.1 years). The yearly rate was 23.8 cases per million in men and 6.0 per million in women. It was highest in the Turku (25.4) and Helsinki (19.0) hospital districts, which the authors said was probably due to the location of the main asbestos-using industrial plants. Compensation claims were filed by 519 men (64.8%) and 34 women (16.3%). Men had 11.0 times the odds of claiming (95% CI 7.5 to 16.2). Patients in the Helsinki and Turku districts combined had 1.7 times the odds of claiming of those elsewhere (95% CI 1.3 to 2.2). Median survival among those who died of the disease was 9.7 months. Survival did not differ by sex, and one-year and three-year survival did not differ by district. Patients without chemotherapy had a higher risk of death (RR 1.8, 95% CI 1.5 to 2.0). After adjustment, no survival benefit from pemetrexed was shown. The authors concluded that claims evaluation is not nationally uniform.

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: Nationwide registry-based cohort study (descriptive epidemiology) using the Finnish Cancer Registry, the National Workers' Compensation Center Registry and the National Registry of Causes of Death
• Who was studied: 1010 patients diagnosed with malignant pleural mesothelioma in Finland during 2000–2012: 801 men (79.3%) and 209 women (20.7%). Follow-up ran to 17 February 2017, when 23 patients were still alive.
• Exposure: The study did not measure individual asbestos exposure or fiber types. It used workers' compensation registry data (claims and occupational disease decisions). It also compared healthcare districts, including the Helsinki (HYKS) and Turku (TYKS) districts, where a major asbestos industry was located (shipyards and asbestos mining locations are shown on a map), with the other districts.
• Main results:
  • Women were older at diagnosis than men: mean age 72.6 years in women versus 68.1 years in men.
  • Incidence of malignant pleural mesothelioma was 14.7 per million per year in the whole cohort. It was 23.8 per million per year in men and 6.0 per million per year in women.
  • Incidence was highest in the Turku district at 25.4 per million per year, followed by Helsinki at 19.0. It was lower in Tampere (9.9), Kuopio (9.4) and Oulu (8.8).
  • Compensation claims were submitted by 519 men (64.8%) and 34 women (16.3%). Mesothelioma was classified as an occupational disease for 528 men (65.9%) and 22 women (10.5%).
  • The odds of submitting a workers' compensation claim were higher for men: OR 11.0 (95% CI 7.5 to 16.2).
  • Patients in the Helsinki and Turku districts combined were more likely to make a compensation claim than patients in the other districts: OR 1.7 (95% CI 1.3 to 2.2).
  • Treatment practices (chemotherapy, radiation therapy, surgery) differed between healthcare districts.
  • Median survival in the group dying of malignant pleural mesothelioma was 9.7 months. 1-year survival was 43.0% and 3-year survival was 11.2%.
  • One-year and three-year survival did not differ between healthcare districts.
  • Survival time did not differ between men and women.
  • Patients not treated with chemotherapy had a higher risk of death than those treated: RR 1.8 (95% CI 1.5 to 2.0). This was after a model accounting for histologic subtype and age.
  • The pemetrexed group initially appeared to survive longer than patients treated with other agents, but the survival curves crossed at 51 months. After adjusting for age and histology, there was no evidence of a survival benefit with pemetrexed.
  • Patients with right-sided disease had a higher risk of death than patients with left-sided disease: RR 1.2 (95% CI 1.03 to 1.4).
• The authors' conclusion: The authors concluded that female patients were older at diagnosis and had fewer workers' compensation claims. They found fewer claims in regions with lower incidence, which they took to indicate that the evaluation process is not nationally uniform, and noted marked differences in treatment between regions. They concluded that awareness of the disease and its occupational cause probably still needs to increase among those caring for these patients. They were unable to show beneficial effects of pemetrexed.
• Limitations the authors state:
  • The authors said the study has limitations shared by most registry studies.
  • Treatment data in clinical reports were less complete than pathology data. Patients without a clinical report were assumed not to have received therapy, so treatment numbers might be slightly underestimated.
  • The registry does not collect performance status, so age was used as an estimate in survival analyses.
  • The study was observational, so differences between patients on different treatments may remain despite statistical adjustment.

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, Occupational Disease, Epidemiology, Cancer Registry, Median Overall Survival, Chemotherapy, Pemetrexed (Alimta).

Related studies

• Evidence for marked underutilization of insurance billing in malignant pleural mesothelioma in Finland — P. Torkki, J. Paajanen, et al. (2021)
• Occupational exposure and regional variation of malignant mesothelioma in Norway, 1970-79 — G. Mowé, B. Gylseth (1986)
• Clinical Features in Patients With Malignant Pleural Mesothelioma With 5-Year Survival and Evaluation of Original Diagnoses — J. Paajanen, S. Laaksonen, et al. (2020)
• Regional variations in German mesothelioma mortality rates: 2000–2010 — S.J. Schonfeld, V. McCormack, et al. (2014)
• Incidence, mortality and survival in malignant pleural mesothelioma before and after asbestos in Denmark, Finland, Norway and Sweden — K. Hemminki, A. Försti, et al. (2021)
• Computed tomography in the evaluation of malignant pleural mesothelioma-Association of tumor size to a sarcomatoid histology, a more advanced TNM stage and poor survival — J. Paajanen, S. Laaksonen, et al. (2018)

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