National survey of malignant mesothelioma and asbestos exposure in Japan

Our plain-English summary of National survey of malignant mesothelioma and asbestos exposure in Japan, by K. Gemba, N. Fujimoto, K. Kato, et al (Cancer Science, 2012).

The study

• Authors: K. Gemba, N. Fujimoto, K. Kato, K. Aoe, Y. Takeshima, K. Inai, T. Kishimoto
• Journal: Cancer Science
• Published: 2012;103(3):483-90
• Cited by: 73 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

In the present study, malignant mesothelioma (MM) cases in Japan were investigated retrospectively. We extracted records for 6030 cases of death due to MM between 2003 and 2008 to clarify the clinical features of MM, including its association with asbestos exposure (AE). Of all these cases, a clinical diagnosis of MM was confirmed for 929. The origin of MM included the pleura in 794 cases (85.5%), the peritoneum in 123 cases (13.2%), the pericardium in seven cases (0.8%), and the testicular tunica vaginalis in five cases (0.5%). The histological subtypes of MM included 396 epithelioid (55.9%), 154 sarcomatoid (21.7%), 126 biphasic (17.8%), and 33 cases (4.7%) classified as "other types". Of all the MM cases, AE was indicated in 76.8% and pleural plaques were detected in 34.2%. The number of asbestos particles was determined in 103 cases of MM. More than 1000 asbestos particles per gram dried lung tissue were detected in 74.8% of cases and more than 5000 particles were detected in 43.7% of cases. We compared patient characteristics and the diagnostic procedures for MM before and after the "Kubota shock". Compared with the early phase of this study (2003-2005), the median age at diagnosis of MM was higher, the number of cases without definite diagnosis of MM was lower, the proportion of cases diagnosed by thoracoscopy was higher, and the percentage of cases in which the occupational history was described in the medical records was significantly higher in the later phase (2006-2008). Our study confirmed that more than 70% of MM cases in Japan are associated with AE. The "Kubota shock" may affect some features pertaining to MM.

© 2011 Japanese Cancer Association.

In plain English

This was a retrospective national survey of malignant mesothelioma in Japan. The authors identified 6030 deaths due to mesothelioma recorded in national Vital Statistics for 2003 to 2008. They obtained relatives' consent in 2069 cases and medical information in 1111, and confirmed the diagnosis in 929. Of these, 794 (85.5%) arose in the pleura and 123 (13.2%) in the peritoneum. Asbestos exposure, judged from work, family and residential histories, was indicated in 633 of the 824 cases with such information (76.8%). Most of this exposure was through work (607 cases), most often in construction and shipbuilding. Pleural plaques were seen in 280 of 818 cases (34.2%). In lung tissue from 103 cases, more than 1000 asbestos particles per gram of dried lung were counted in 77 (74.8%). Patients who died in 2006 to 2008 had a higher median age at diagnosis than those who died in 2003 to 2005 (69.4 vs 66.4 years), and were more often diagnosed by thoracoscopy or laparoscopy. The authors concluded that more than 70% of mesothelioma cases in Japan are associated with asbestos exposure.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective national survey of mesothelioma deaths identified from Japan's Vital Statistics death records, with review of medical records and images, family questionnaires, and lung asbestos particle counts
• Who was studied: 6030 deaths due to malignant mesothelioma in Japan between 2003 and 2008. Relatives' consent was obtained in 2069 cases (34.3%) and medical information in 1111 cases. A clinical diagnosis of mesothelioma was confirmed in 929 cases (753 men, 176 women; median age at diagnosis 67.0 years).
• Exposure: Asbestos exposure assessed from patients' work histories, family members' histories and residential histories in medical records and family questionnaires. Pleural plaques were assessed on chest X-ray and/or CT. Asbestos particles per gram of dried lung tissue were counted by phase contrast microscopy in available lung tissue. Fiber types were not identified in this study.
• Main results:
  • Among the 929 confirmed cases, mesothelioma arose in the pleura in 794 (85.5%), the peritoneum in 123 (13.2%), the pericardium in 7 (0.8%) and the testicular tunica vaginalis in 5 (0.5%)
  • Of 709 cases with a recorded histological subtype: 396 epithelioid (55.9%), 154 sarcomatoid (21.7%), 126 biphasic (17.8%), 33 other types (4.7%)
  • Information on asbestos exposure was obtained in 824 of the 929 confirmed cases. Among these 824, occupational exposure was indicated in 607 (73.7%).
  • Overall, asbestos exposure was indicated in 633 of the 824 cases (76.8%). This included 18 cases with neighborhood exposure (9 of them had lived in Amagasaki city near the Kubota plant) and 8 cases with home exposure.
  • Among the 607 occupationally exposed cases, 131 (21.6%) had worked in construction, 91 (15.0%) in shipbuilding, 46 (7.6%) in plumbing, 44 (7.2%) in electrical work, 41 (6.8%) in steel production and 36 (5.9%) in manufacturing asbestos products
  • In occupationally exposed cases, the median latency to disease onset was 43.5 years for pleural mesothelioma and 42.5 years for peritoneal mesothelioma
  • Pleural plaques were detected in 280 of 818 cases (34.2%). This included 242 of 703 pleural mesothelioma cases (34.4%) and 36 of 106 peritoneal mesothelioma cases (33.9%).
  • Pleural plaque prevalence was 75.8% among those who worked in manufacturing asbestos products and 58.6% among shipbuilding workers. Plaques were also found in 31 cases (13.5%) without an obvious occupational history of asbestos exposure.
  • In 103 cases with lung tissue (92 pleural, 11 peritoneal), more than 1000 asbestos particles per gram of dried lung were found in 77 (74.8%). More than 5000 were found in 45 (43.7%).
  • Asbestos particles were more frequently detected in peritoneal than in pleural mesothelioma (P = 0.046). In pleural cases, more than 1000 particles were found in 67 (72.8%) and more than 5000 in 37 (40.2%). In peritoneal cases, more than 1000 were found in 10 (90.9%) and more than 5000 in 8 (72.7%).
  • More than 5000 particles were detected in seven of eight asbestos products workers (printed as 90.9%), in 16 of 21 shipbuilding workers (76.2%) and in 9 of 17 construction workers (52.9%)
  • In 16 cases without occupational asbestos exposure, more than 1000 particles were found in 8 (50%) and more than 5000 in 1 (6.3%)
  • Cases with pleural plaques had increased asbestos particle counts (P less than 0.001). Even so, more than 1000 particles per gram were found in 32 of 55 cases without plaques (58.2%).
  • Median age at diagnosis was higher in patients who died in 2006 to 2008 (late phase) than in those who died in 2003 to 2005 (early phase): 69.4 vs 66.4 years, P less than 0.001
  • Suspected mesothelioma without pathological confirmation decreased from 70 cases (9.4%) in the early phase to 26 cases (7.0%) in the late phase (P less than 0.001)
  • Diagnosis by thoracotomy or laparotomy fell from 150 cases (29.8%) in the early phase to 16.2% in the late phase (P less than 0.001). Diagnosis by thoracoscopy or laparoscopy rose from 34.0% to 58.8% (P less than 0.001).
  • Occupational history was recorded in the medical records for 28.7% of patients in the early phase and 62.4% in the late phase, reported as a significant increase
• The authors' conclusion: The authors concluded that more than 70% of mesothelioma cases in Japan are associated with asbestos exposure, and that the 'Kubota shock' may affect some features pertaining to mesothelioma. They also wrote that the presence of pleural plaques is not sufficient for evaluating a history of asbestos exposure.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Asbestos Exposure, Pleura, Peritoneum, Pericardium, Tunica Vaginalis, Histological Subtype, Epithelioid.

Related studies

• Fatal pleural mesothelioma in Japan (2003-2008): evaluation of computed tomography findings — K. Kato, K. Gemba, et al. (2016)
• Treatment and survival analyses of malignant mesothelioma in Japan — K. Gemba, N. Fujimoto, et al. (2013)
• Clinical investigation of malignant mesothelioma in Japan — N. Fujimoto, K. Aoe, et al. (2010)
• Survival and prognostic factors in malignant pleural mesothelioma: a retrospective study of 314 patients in the west part of Japan — S. Nojiri, K. Gemba, et al. (2011)
• Quality of life of survivors of malignant pleural mesothelioma in Japan: a cross sectional study — Y. Nagamatsu, I. Oze, et al. (2018)
• Incidence of interstitial lung disease in patients with mesothelioma in the west part of Japan — S. Nojiri, K. Gemba, et al. (2011)

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