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

The study analyzed survival after malignant mesothelioma in the population-based Registry of Malignant Mesothelioma of Piedmont (NW Italy, 4.5 million total population). It focused on possible differences related to period of diagnosis a proxy of changes in diagnostic or therapeutic procedures.

Cases were actively searched in pathology units and files of hospital admissions and discharges. In 1990-1998, 693 incident cases were diagnosed in residents in the region: 590 of them had a histologic diagnosis of pleural mesothelioma in life and were included in the study. Vital status was ascertained at the municipality of residence as of January 1, 2000.

Fifty-eight cases were alive (9.8%) and 20 were lost (3.6%) at the end of the follow-up. Median survival was 0.71 years (95% CI, 0.64-0.78). Cumulative survival was 35.9% at 1 year (95% CI, 32.0-39.8) and 14.2% at 2 years (95% CI, 11.2-17.1). Survival was associated to age (longer survival for younger subjects at diagnosis; P <0.0001) and to histology (longer survival for epithelial mesothelioma, shorter for fibrous and intermediate for mixed or unspecified types; P <0.0001). There was no difference in survival for period of diagnosis. The results were confirmed in multivariate analyses. Analyses according to type of hospital (with vs without thoracic surgery) did not show any statistically significant difference.

The study on survival after malignant mesothelioma is the second largest of the three population-based studies in the world, which showed results similar to ours. Survival measured in published clinical series ranged between 18.4% and 57.6% at 1 year for pleural and 24.1% and 33.8% for peritoneal mesothelioma. The most striking effect of the present study was the absence of improvement in survival with period of diagnosis. Either there was no change in treatment efficacy or the effect was limited to small subgroups and could not be noticed when the analysis included larger categories.