Asbestos exposure and survival in malignant mesothelioma: a description of 122 consecutive cases at an occupational clinic

BACKGROUND: The natural history and etiology of malignant mesothelioma (MM) is already thoroughly described in the literature, but there is still debate on prognostic factors, and details of asbestos exposure and possible context with clinical and demographic data, have not been investigated comprehensively.

OBJECTIVE: Description of patients with MM, focusing on exposure, occupation, survival and prognostic factors.

METHODS: Review of medical records of patients with MM from 1984 to 2010 from a Danish Occupational clinic. Survival was estimated using Kaplan-Meier survival analysis and prognostic factors were identified by Cox regression analysis.

RESULTS: 110 (90.2%) patients were male, and 12 (9.8%) were female. The median (interquartile rang [IQR]) age was 65 (13) years. Pleural MM was seen in 101 (82.8%) patients, and peritoneal in 11 (9.0%); two (1.6%) had MM to tunica vaginalis testis, and eight (6.6%) to multiple serosal surfaces. We found 68 (55.7%) epithelial tumors, 26 (21.3%) biphasic, and 6 (4.9%) sarcomatoid. 12 (9.8%) patients received tri-modal therapy, 66 (54.1%) received one-/two-modality treatment, and 36 (29.5%) received palliative care. Asbestos exposure was confirmed in 107 (91.0%) patients, probable in four (3.3%), and unidentifiable in 11 (9.0%). The median (IQR) latency was 42 (12.5) years. Exposure predominantly occurred in shipyards. The median overall survival was 1.05 (95% CI: 0.96-1.39) years; 5-year survival was 5.0% (95% CI: 2.0%-13.0%). Female sex, good WHO performance status (PS), epithelial histology and tri-modal treatment were associated with a favorable prognosis.

CONCLUSION: MM continuously presents a difficult task diagnostically and therapeutically, and challenges occupational physicians with regard to identification and characterization of asbestos exposure.