Clinical investigation of malignant mesothelioma in Japan

Our plain-English summary of Clinical investigation of malignant mesothelioma in Japan, by N. Fujimoto, K. Aoe, K. Gemba, et al (Journal of Cancer Research and Clinical Oncology, 2010).

The study

• Authors: N. Fujimoto, K. Aoe, K. Gemba, K. Kato, K. Yamazaki, T. Kishimoto
• Journal: Journal of Cancer Research and Clinical Oncology
• Published: 2010;136(11):1755-9
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Purpose: The asbestos-related problems caused much social concern; however, no large-scale study was conducted about clinical features of MM in Japan. Patients with MM who have a history of occupational asbestos exposure (AE) are provided worker's compensation in Japan. However, only about 10% of MM cases were actually claimed and compensated. So there is still controversy over the association between MM and AE. The aim of this study is to investigate the clinical features of MM. We also aimed to clarify the association between MM and occupational AE in Japan.

Methods: We examined the clinical features of MM cases. Clinical information was obtained including gender, age, site of origin, pathological subtype, radiological findings, and treatment outcome. To investigate the association between MM and AE, investigators interviewed all patients regarding work and residential history.

Results: Between January 2005 and December 2007, 105 cases (median age: 63 years, range 35-80, male/female: 88/17) were diagnosed with MM in the Rosai Hospital group and related facilities. Among them, 94(89.5%) cases originated in the pleura, 7(6.7%) in the peritoneum, 2(1.9%) in the pericardium, and 1(0.9%) in the tunica vaginalis testis. There were 69(65.7%) epithelioid, 19(18.1%) biphasic, 16(15.2%) sarcomatoid, and 1 unclassified pathological subtypes of MM. A favorable survival rate was indicated in the patient group of MPM that underwent surgery compared to others, though it was not statistically significant (P = 0.1743). The occupational AE was indicated in 89 cases (84.8%). Three patients had no history of occupational AE, but lived with someone who was in an occupation that handled asbestos. There were two patients in which AE was indicated in their life environment. Altogether, AE was indicated in 93(88.6%) patients.

Conclusions: This study stresses the urgent need for physicians to acknowledge the association between MM and AE, and to inquire thoroughly regarding AE to the patients with MM.

In plain English

This study described 105 people with malignant mesothelioma treated from January 2005 to December 2007 at Rosai Hospitals and related facilities in Japan; some were diagnosed earlier. Their median age was 63; 88 were men and 17 women. The cancer began in the pleura (chest lining) in 94, peritoneum in 7, pericardium in 2 and tunica vaginalis testis in 1; one site was undetermined. Imaging showed pleural plaques in 42 of 103, asbestosis in none. Pleural mesothelioma patients diagnosed 2005 to 2007 had median survival of 13.2 months (95% confidence interval 11.23 to 15.17). From diagnosis, median survival was 15.1 months (interval 10.23 to 20.04) in the surgery group versus 12.7 (8.95 to 16.45) in other groups, not statistically significant; the authors noted selection bias. Interviews found occupational asbestos exposure in 89 (84.8%), most often in shipbuilding and construction. Three others lived with an asbestos worker, 2 near an asbestos products factory; the article totals 93 (88.6%) exposed, though these add to 94. Twelve had no exposure history. The authors concluded that a strong association with occupational asbestos exposure was demonstrated.

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: Multicenter clinical case series of mesothelioma patients, with face-to-face interviews about work, family and residential history
• Who was studied: 105 patients with malignant mesothelioma at Rosai Hospitals and related facilities in Japan who were diagnosed and in treatment between January 2005 and December 2007. Patients diagnosed earlier (the article says before 2004) who were still in treatment in 2005 were also included. Median age 63 (range 35 to 80); 88 men and 17 women.
• Exposure: Asbestos exposure assessed by interview: occupational, through family members' jobs, and residential or environmental. No fiber types were reported.
• Main results:
  • Site of origin among the 105 cases: pleura 94 (89.5%), peritoneum 7 (6.7%), pericardium 2 (1.9%), tunica vaginalis testis 1 (0.9%). In one further case the origin (pleura or pericardium) was undetermined.
  • Pathological subtypes: 69 (65.7%) epithelioid, 19 (18.1%) biphasic, 16 (15.2%) sarcomatoid, 1 unclassified
  • Among the 103 patients with radiological findings: pleural effusion in 74 (71.8%), pleural plaque in 42 (40.8%), and no asbestosis
  • Among the 88 pleural mesothelioma patients with radiological findings: pleural effusion in 69 (78.4%) and pleural plaque in 35 (39.8%)
  • Of 94 pleural mesothelioma patients, 36 had surgery as the principal treatment
  • Median overall survival of pleural mesothelioma patients diagnosed 2005 to 2007 was 13.2 months (95% confidence interval 11.23 to 15.17). Survival was measured from the day of diagnosis to death or last follow-up.
  • Pleural mesothelioma, stages I and II: median survival 17.9 months (95% C.I. 9.07 to 26.66). Stages III and IV: 12.8 months (95% C.I. 10.34 to 15.19). P = 0.0707.
  • Pleural mesothelioma, median overall survival measured from diagnosis. Surgery group: 15.1 months (95% C.I. 10.23 to 20.04). Other groups: 12.7 months (95% C.I. 8.95 to 16.45). P = 0.1743. The authors reported these survival differences as not statistically significant.
  • Occupational asbestos exposure was indicated in 89 of 105 cases (84.8%), including 23 in shipbuilding, 16 in construction, 9 in plumbing, 8 in electrical work and 7 in manufacturing
  • Exposure outside work: 3 patients without occupational exposure lived with someone whose job handled asbestos, and 2 had exposure from their living environment (near an asbestos products factory). The article gives a total of 93 (88.6%) exposed patients, although 89, 3 and 2 add to 94.
  • 12 of the 105 patients had no history of occupational or environmental asbestos exposure
  • Median duration of asbestos exposure was 29 years (range 1 to 60). Median time from first exposure to mesothelioma was 41 years (range 4 to 60).
• The authors' conclusion: The authors concluded that a strong association with occupational asbestos exposure was demonstrated in these Japanese mesothelioma cases.
• Limitations the authors state:
  • The authors stated that survival comparisons after treatment must be interpreted carefully because of patient selection bias: surgery was offered to selected patients with earlier stage and better performance status.

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, Epithelioid, Biphasic Mesothelioma.

Related studies

• Treatment and survival analyses of malignant mesothelioma in Japan — K. Gemba, N. Fujimoto, et al. (2013)
• Clinical Investigation of Benign Asbestos Pleural Effusion — N. Fujimoto, K. Gemba, et al. (2015)
• Clinical study of asbestos-related lung cancer in Japan with special reference to occupational history — T. Kishimoto, K. Gemba, et al. (2010)
• National survey of malignant mesothelioma and asbestos exposure in Japan — K. Gemba, N. Fujimoto, et al. (2012)
• Fatal pleural mesothelioma in Japan (2003-2008): evaluation of computed tomography findings — K. Kato, K. Gemba, et al. (2016)
• Malignant pleural mesothelioma in parts of Japan in relationship to asbestos exposure — T. Kishimoto, S. Ozaki, et al. (2004)

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