Survival of pleural malignant mesothelioma in Italy: a population-based study

Our plain-English summary of Survival of pleural malignant mesothelioma in Italy: a population-based study, by F. Montanaro, R. Rosato, M. Gangemi, et al (International Journal of Cancer, 2009).

The study

• Authors: F. Montanaro, R. Rosato, M. Gangemi, S. Roberti, F. Ricceri, E. Merler, V. Gennaro, A. Romanelli, E. Chellini, C. Pascucci, M. Musti, C. Nicita, P.G. Barbieri, A. Marinaccio, C. Magnani, D. Mirabelli
• Journal: International Journal of Cancer
• Published: 2009;124(1):201-7
• Cited by: 107 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A median survival time of about 9 months is generally reported among malignant pleural mesothelioma cases. Recently, better results in terms of survival and performance status have been reported in clinical trials that included highly selected patients. We describe the survival of pleural mesothelioma patients and the factors predictive of survival in an unselected, population-based setting. Pleural mesothelioma cases (4,100) registered from 1990 to 2001 by 9 Italian regional mesothelioma registries contributing to the network of the National Mesothelioma Registry were followed until December 31, 2005. Univariate (Kaplan-Meier) and multivariate (Cox proportional hazards regression) analyses of survival were carried out according to selected individual characteristics, including limited information on treatment in a subset of 578 cases. The median survival time was 9.8 months (95% confidence interval: 9.4-10.1). In multivariate analysis, younger age at diagnosis and epithelioid histotype were associated with significantly reduced hazard ratios. Positive effects of gender (women) and being diagnosed in a hospital with a thoracic surgery unit were of border-line statistical significance. No association with calendar period of diagnosis or asbestos exposure was present. Treatment was not associated with a statistically significant improvement in survival. This is the largest population-based study on survival in patients with pleural mesothelioma to date. Age and morphology were the main prognostic factors. Results regarding the effect of treatment were disappointing but may be useful to assess the future impact, at the population level, of recently introduced therapies.

In plain English

This population-based study examined survival of malignant pleural mesothelioma patients in Italy. The authors used 4,100 cases with a definite or probable diagnosis, first diagnosed from 1990 to 2001 and recorded by nine regional registries in the National Mesothelioma Registry, followed to December 31, 2005. The median survival time was 9.8 months (95% confidence interval 9.4–10.1). Less than 10% of patients were alive 3 years after diagnosis, and 5% after 5 years. In the main statistical model, the risk of death rose with age (hazard ratio 1.9, 95% confidence interval 1.7–2.1, for ages 75 and over versus under 55). It was higher for fibrous tumours (1.8, 1.6–2.0) and mixed tumours (1.4, 1.3–1.6) than for epithelioid tumours. Men, and people diagnosed in hospitals without a thoracic surgery unit, had slightly higher hazard ratios. Asbestos exposure had no significant effect, and there was no trend by period of diagnosis. In 578 patients with treatment information, treatment was not associated with a statistically significant improvement in survival. The authors noted that disease stage and performance status were unknown, and that their findings cannot prove or disprove treatment effectiveness.

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: Population-based survival study using mesothelioma registry data (Kaplan-Meier and Cox proportional hazards analyses)
• Who was studied: 4,100 malignant pleural mesothelioma cases (2,995 men, 1,105 women) with a definite or probable diagnosis. They were first diagnosed from 1990 to 2001 and registered by 9 Italian regional registries (Piemonte, Veneto, Liguria, Emilia-Romagna, Toscana, Marche, Puglia, Sicilia, Province of Brescia), and followed until December 31, 2005.
• Exposure: Asbestos exposure was classified only as ever exposed (occupationally or non-occupationally; 2,204 cases), never exposed (122 cases), or unknown (1,774 cases). No fiber types were reported. Treatment (non-palliative surgery, chemotherapy and/or radiotherapy) was also studied in a subset of cases.
• Main results:
  • Among all 4,100 patients, the median survival time was 9.8 months (95% confidence interval: 9.4–10.1).
  • Less than 10% of all patients were alive 3 years after diagnosis, and 5% were alive after 5 years.
  • Among all patients, the hazard ratio for death increased with age compared with those under 55: 1.3 (1.1–1.4) for ages 55–64, 1.4 (1.3–1.5) for 65–74, and 1.9 (1.7–2.1) for 75 and over.
  • Compared with the epithelioid subtype, hazard ratios were 1.4 (1.3–1.6) for mixed, 1.8 (1.6–2.0) for fibrous, and 1.3 (1.2–1.4) for unspecified morphology. Fibrous tumours had the worst prognosis.
  • Marginally but significantly increased hazard ratios were found for men compared with women (1.1, 1.0–1.2, p=0.013) and for diagnosis in hospitals without a thoracic surgery unit (1.2, 1.1–1.3, p<0.001). In the discussion, the authors called the gender difference slight and only of borderline significance.
  • In the multivariate model, asbestos exposure had no significant effect on survival: never exposed versus exposed, hazard ratio 0.9 (0.7–1.1), p=0.235. In the univariate analysis, exposed patients showed better survival. The authors discussed possible reasons such as quicker diagnosis and interview quality.
  • No trend was seen by calendar period of diagnosis, although slight increases in hazard ratios were present in 1990–1992 and 1996–1998.
  • The share of long-term survivors (48 months or more; 261 patients in total) reached 8% for cases diagnosed in 1999–2001, versus 3.7% in 1990–1992.
  • Among 578 cases with definite treatment information (427 ever treated, 151 never treated), treatment showed a slight effect that was not statistically significant. The hazard ratio for untreated versus treated was 1.3 (0.9–1.8), p=0.148.
  • In the Liguria cases, the only group with smoking data, no effect of smoking on survival was detected.
• The authors' conclusion: The authors concluded that, within the limits of their data, treatment for malignant pleural mesothelioma did not seem to be associated with significant improvements in survival. They added that their findings cannot prove or disprove treatment effectiveness, and that age and morphology were the main prognostic factors.
• Limitations the authors state:
  • No national panel reviewed the diagnostic evidence, so some misclassification of diagnosis is possible.
  • Disease stage and performance status were not known and could not be controlled for.
  • Treatment information was available only for a subset of cases and did not include details of the specific chemotherapy or radiotherapy regimens.
  • Treated patients are likely to differ from untreated patients in other ways, such as age, performance status and stage of disease.
  • The results do not apply to the most recent therapeutic approaches.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Median Overall Survival, Pleural Mesothelioma, Performance Status, Clinical Trial, confidence interval, Multivariate Analysis, Epithelioid.

Related studies

• Survival after pleural malignant mesothelioma: a population-based study in Italy — C. Magnani, S. Viscomi, et al. (2002)
• Survival of malignant pleural mesothelioma cases in the Tuscan Mesothelioma Register, 1988-2000: a population-based study — G. Gorini, G. De Gregorio, et al. (2005)
• Non-occupational exposure to asbestos and malignant mesothelioma in the Italian National Registry of Mesotheliomas — D. Mirabelli, D. Cavone, et al. (2010)
• Treatment patterns among patients with malignant pleural mesothelioma: An Italian, population-based nationwide study — A. Trama, C. Proto, et al. (2020)
• Epidemiological patterns of asbestos exposure and spatial clusters of incident cases of malignant mesothelioma from the Italian national registry — M. Corfiati, A. Scarselli, et al. (2015)
• Pleural malignant mesothelioma epidemic: incidence, modalities of asbestos exposure and occupations involved from the Italian National Register — A. Marinaccio, A. Binazzi, et al. (2012)

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