Pulmonary Asbestos Fiber Burden Is Related to Patient Survival in Malignant Pleural Mesothelioma.

INTRODUCTION

Malignant pleural mesothelioma (MPM) is associated with poor prognosis and is strongly associated with occupational asbestos exposure. Given the importance of asbestos exposure in MPM pathogenesis, we retrospectively analyzed the types and concentrations of asbestos fibers within the lung tissues of patients with MPM and investigated their effects on all-cause mortality.

METHODS

We formed a national data set of patients with MPM identified from the Finnish Cancer Registry and Statistics Finland. These data were merged with pulmonary asbestos fiber analysis results received from the Finnish Institute of Occupational Health.

RESULTS

We identified 590 patients with MPM who underwent pulmonary asbestos fiber analysis. The median asbestos concentration within dry lung tissue was 3.20 million fibers/gram (range: 0 - 1700 million fibers/gram). Crocidolite and anthophyllite were the most prevalent asbestos fiber types detected in lung tissue. The multivariable risk of death analyses, where changes over time were accounted for, revealed that total asbestos fiber concentration was associated with increased mortality. Nevertheless, no difference in mortality was noted between different fiber types.

CONCLUSIONS

Our study revealed that pulmonary fiber concentrations correlated with the manner of asbestos usage. Anthophyllite was identified as the sole fiber in a sizable proportion of cases, supporting its independent role in the pathogenesis of MPM. Our findings suggest that asbestos fiber burden, but not fiber type, may have an impact on the prognosis of MPM.