Asbestos-related malignant mesothelioma in Japan

Abstract

18182 Large amounts of asbestos use from 1960’s induced the increase of death caused by malignant mesothelioma in Japan. However, a national survey of the relationship between malignant mesothelioma and asbestos exposure, as well as diagnosis and treatment of malignant mesothelioma has not done up to today. One hundred and fifty-three cases of malignant mesothelioma diagnosed and treated in the Rosai Hospitals located all over Japan were studied, and 132 cases (80.4%) proved to be the definite diagnosis of malignant mesothelioma; another 21 cases were diagnosed as lung cancer, etc. As for definite 132 cases, 105 cases are male and other 27 cases are female with the ratio of 3.9:1. Ages ranges from 28 to 92 years old with the mean of 66.2 years old. One hundred and twelve cases originated from pleura, 18 cases from peritoneum, and each one case originated from pericardium and testicular tunica vaginalis. Final diagnosis of 104 cases (78.8%) was done by the tumor tissues. According to IMIG classification, stage I was 29 cases, stage II 6 cases, stage III 28 cases and stage IV was 44 cases. For the treatment, 29 cases were done extrapleurectomy, 58 cases were chemotherapy and other 39 cases were best supportive care. Median survival term of 132 cases were 9.5 months with 9.8 months of pleural origin and 5.6 months of peritoneal origin. By the clinical staging, stage I and II were 17.2 months, stage III 10.4 months and stage IV 5.4 months. By the treatment, extrapleurectomy was 18.1 months, chemotherapy 8.0 months and palliative care was 5.7 months. Seventy six percent cases were induced by occupational asbestos exposure and the mean exposuring time was 27.6 years and the mean latency was 43 years. Occupational histories were mainly shipbuilders, carpenters, electricians and piping workers. Summary: Seventy-six percent of Japanese malignant mesothelioma appeared by the occupational exposure to asbestos. Seventy-eight percent of final diagnosis were done by histological examination of tumor tissue. Extrapleurectomy was effective for the prognosis. [Table: see text] No significant financial relationships to disclose.