Incidence of cancer among Finnish patients with asbestos-related pulmonary or pleural fibrosis

Our plain-English summary of Incidence of cancer among Finnish patients with asbestos-related pulmonary or pleural fibrosis, by A. Karjalainen, E. Pukkala, T. Kauppinen, et al (Cancer Causes & Control, 1999).

The study

• Authors: A. Karjalainen, E. Pukkala, T. Kauppinen, T. Partanen
• Journal: Cancer Causes & Control
• Published: 1999;10(1):51-7
• Cited by: 31 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: To study the asbestos-associated risk of lung cancer according to the histological type of cancer, the time of and time since diagnosis of asbestosis, the asbestos-associated risk for cancers other than lung cancer or mesothelioma, and the predictive value of asbestos-related pleural abnormalities as regards the risk of cancer.

Methods: Finnish patients with asbestosis (n = 1,376) or asbestos-related benign pleural disease (n = 4,887) notified as an occupational disease since 1964 were followed-up through the Finnish Cancer Registry for cancer in 1967-95.

Results: Compared with the total cancer incidence in Finland, men with asbestosis had a raised risk of lung cancer (standardized incidence ratio [SIR] = 6.7; 95% confidence interval [CI] = 5.6-7.9), mesothelioma (SIR = 32, CI = 14-60) and cancer of the larynx (SIR = 4.2, CI = 1.4-9.8). The risk of lung cancer was similarly raised for all histological types of lung cancer (the highest in insulators) and did not change markedly over time of notification or duration of follow-up. Men with benign pleural disease had a raised risk of mesothelioma (SIR = 5.5, CI = 1.5-14) and a slightly elevated risk of lung cancer (SIR = 1.3, CI = 1.0-1.8). Among women with asbestosis, significant excess was found for lung cancer and mesothelioma.

Conclusion: Asbestosis and asbestos-related benign pleural disease seem to possess different predictive values as regards the risk of lung cancer.

In plain English

This Finnish study followed 1,376 people with asbestosis (scarring of the lungs) and 4,887 people with asbestos-related benign pleural disease. All had been reported to the national registry of occupational diseases by the end of 1995. The authors checked the Finnish Cancer Registry for cancers through 1995 and compared the numbers with those expected from cancer rates in Finland. Men with asbestosis had 198 cancers, compared with 75.5 expected. Their lung cancer risk was 6.7 times expected (95% confidence interval 5.6 to 7.9). It was raised for all main types of lung cancer and was highest among insulators. These men also had raised risks of mesothelioma and of cancer of the larynx. Men with benign pleural disease had a raised risk of mesothelioma and a slightly raised risk of lung cancer (1.3 times expected, interval 1.0 to 1.8). Women with asbestosis had raised risks of lung cancer and mesothelioma, based on 6 cases and 1 case. No data on smoking were collected. The authors concluded that asbestosis and benign pleural disease have different predictive values for lung cancer risk.

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: Registry-based cohort study comparing observed cancer cases with the numbers expected from Finnish national cancer rates (standardized incidence ratios)
• Who was studied: Patients reported to the Finnish Registry of Occupational Diseases by the end of 1995: 1,376 with asbestosis (1,287 men, 89 women) and 4,887 with asbestos-related benign pleural disease (4,708 men, 179 women). Asbestosis has been reported since 1964 and benign pleural disease since 1987. Cancer follow-up ran from 1967 to 1995.
• Exposure: Confirmed occupational exposure to asbestos. The median duration of reported exposure was 25 years for patients with asbestosis and 26 years for patients with pleural disease.
• Main results:
  • Men with asbestosis had 198 cancers of all types, compared with 75.5 expected (SIR 2.6, CI 2.3 to 3.0).
  • Men with asbestosis had 127 lung cancers (SIR 6.7, CI 5.6 to 7.9).
  • Among men with asbestosis, lung cancer was raised for all histological types: adenocarcinoma 20 cases (SIR 8.6, CI 5.2 to 13.2), squamous cell carcinoma 37 cases (SIR 5.9, CI 4.1 to 8.1), and small cell carcinoma 28 cases (SIR 9.1, CI 6.0 to 13.1).
  • Men with asbestosis also had raised risks of mesothelioma (9 cases, SIR 31.6, CI 14.4 to 60.0) and cancer of the larynx (5 cases, SIR 4.2, CI 1.4 to 9.8).
  • Among men with asbestosis, lung cancer risk was highest in insulators (47 cases among 188 insulators, SIR 11.3, CI 8.3 to 15.1).
  • Among men with asbestosis, lung cancer risk was already raised in the first years after notification (0 to 4 years: SIR 6.2, CI 4.7 to 7.9) and did not change markedly thereafter. Men whose asbestosis was notified in 1987 to 1995 still had raised risk (SIR 5.9, CI 4.3 to 8.0).
  • Men with benign pleural disease had 157 cancers of all types (SIR 1.1, CI 0.9 to 1.3). Their risk of mesothelioma was raised (4 cases, SIR 5.5, CI 1.5 to 14.1) and their risk of lung cancer was slightly raised (44 cases, SIR 1.3, CI 1.0 to 1.8).
  • Lung cancer incidence was 18 per 1,000 person-years in men with asbestosis and 2.9 per 1,000 person-years in men with benign pleural disease.
  • Women with asbestosis had 18 cancers (SIR 2.8, CI 1.7 to 4.4), including 6 lung cancers (SIR 19.8, CI 7.3 to 43.1) and 1 mesothelioma (SIR 95.7, CI 2.4 to 533).
  • Women with benign pleural disease had 9 cancers (SIR 1.9, CI 0.9 to 3.7), none of them lung cancers or mesotheliomas.
  • There were no clear trends in lung cancer risk by duration of reported exposure.
  • The authors found no indication of elevated risk of kidney or colon cancer.
• The authors' conclusion: The authors concluded that asbestosis and asbestos-related benign pleural disease have different predictive values as regards lung cancer risk, and that a diagnosis of asbestosis still indicates a high risk of lung cancer.
• Limitations the authors state:
  • No data on smoking or other non-occupational exposures were collected. The authors note that smoking probably influenced the lung cancer estimates.
  • The authors judged that the duration of exposure taken from notification reports is probably a poor indicator of total cumulative asbestos exposure.
  • The data did not allow analysis of cancer risk by the clinical or radiographic severity of asbestosis.
  • Only a few mesotheliomas were observed.
  • Diagnostic procedures may have varied. The authors therefore also analyzed a subset of patients notified by the Finnish Institute of Occupational Health.
  • Underdiagnosis of mesothelioma in the 1960s and 1970s may have contributed to the high ratio of lung cancer to mesothelioma.

Topics

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

Medical terms in this study, explained in our Lexicon: Fibrosis, Lung Cancer, Mesothelioma, Occupational Disease, Cancer Registry, Standardized Incidence Ratio (SIR), confidence interval, Laryngeal Cancer.

Related studies

• Finnish Institute of Occupational Health (FIOH): prevention and detection of asbestos-related diseases, 1987-2005 — M.S. Huuskonen, J. Rantanen (2006)
• Past exposure to asbestos and combustion products and incidence of cancer among Finnish locomotive drivers — P. Nokso-Koivisto, E. Pukkala (1994)
• Cancer incidence and mortality among Finnish asbestos sprayers and in asbestosis and silicosis patients — P. Oksa, E. Pukkala, et al. (1997)
• Commentary regarding the article by Fischer et al.: Fibre years, pulmonary asbestos burden and asbestosis. Int. J. Hyg. Environ. Health 205, 245-248 (2002) — D.W. Henderson (2003)
• Commentary regarding the article by Fischer et al.: Fibre years, pulmonary asbestos burden and asbestosis. Int. J. Hyg. Environ. Health 205, 245-248 (2002) — K. Rödelsperger, H.J. Woitowitz (2003)
• Pulmonary function and pleural fibrosis: quantitative relationships with an integrative index of pleural abnormalities — R. Lilis, A. Miller, et al. (1991)

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