Malignant mesothelioma - German mesothelioma register 1987-1999

Objectives: The study group comprised a collective of 1,605 patients with m alignant mesotheliomas and with lung tissue available for lung dust analyse s. Method: Clinical features, occupational histories, expositions and indiv idual data were evaluated, and the asbestos bodies concentrations (asbestos bodies/cm(3) lung tissue or g wet tissue) were determined. Results: Mesoth eliomas developed mainly in men (94.5%). Of the cases, 96.4% were of pleura l origin and only 3.3% were peritoneal mesotheliomas. The biphasic subtype predominated (61.3%), followed by the epithelioid type (29.3%). The sarcoma toid subtype was rarely developed (9.4%). Mean age at first diagnosis was 6 0.4 years. The mean survival time from time of symptom onset was 13.5 month s. Patients with epithelioid subtypes had a longer survival time (16.9 mont hs) than those with biphasic (13.1 months) and sarcomatoid subtypes (5.5 mo nths). Of the patients, 73% presented pleural effusions as initial symptoms of the disease. An increased asbestos burden was identified by light micro scopy in 84.8% of the patients. There was no association between histologic al subtypes and the asbestos burden of the lungs. Patients with peritoneal mesotheliomas had distinctly higher asbestos burdens in the lungs than pati ents with pleural mesotheliomas. There exists no association between lung a sbestos burdens and survival times. The mean latency period was 37.8 years. A trend: higher asbestos burden of the lung/shorter latency periods was su ggested. About 70% of the patients had a history of occupational exposure t o asbestos dust. Most patients worked in the building trade, the locksmith and machine building industries and in the steel and blast-furnace industri es. Of the patients, 25.6% had asbestos-associated lung fibroses, in 40.7% of the cases pleural plaques were identified. Conclusions: The most importa nt causal factor for development of mesotheliomas is still asbestos, primar ily amphibole asbestos. The recurring occurrence of mesotheliomas in younge r people without known asbestos exposure needs the urgent investigation of other inducing factors for mesotheliomas.