Malignant mesothelioma in Hong Kong

Our plain-English summary of Malignant mesothelioma in Hong Kong, by K.C. Chang, C.C. Leung, C.M. Tam, et al (Respiratory Medicine, 2006).

The study

• Authors: K.C. Chang, C.C. Leung, C.M. Tam, W.C. Yu, D.S. Hui, W.K. Lam
• Journal: Respiratory Medicine
• Published: 2006;100(1):75-82
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant mesothelioma (mesothelioma) is rare. We conducted the first systematic study of the epidemiology of mesothelioma in Hong Kong from 1988 to May 2002 by reviewing medical records. Mesothelioma patients were identified from the database of 12 out of 20 hospitals that would have admitted mesothelioma patients territory-wide. These 12 hospitals served 73% of the total hospital bed-years of the 20 hospitals. We identified 67 mesothelioma patients. The estimated annual incidence was one per million, which was similar to the background incidence of one to two per million among Caucasians. Occupational history was available in 43 subjects. Three quarters of mesothelioma patients with available occupational history had occupational asbestos exposure. Restricting analysis to 48 patients with accessible medical records and using 67 occupational asbestosis patients for comparison, the epidemiology of mesothelioma in Hong Kong shares similarities with the literature: mean age of 63 years upon diagnosis, mean latency of 46 years, median survival of 9.5 months, male predominance, selective presentation among women, high prevalence among workers in ships and dockyards, predominantly epithelioid type, lower prevalence of asbestos bodies, and negative association with pleural plaques. Asbestos consumption in Hong Kong rose in the 1970s and peaked in early 1980s and late 1990s. Hong Kong may encounter an epidemic of mesothelioma in the 2010s if effective occupational asbestos control measures are not in place.

In plain English

This study reviewed medical records of malignant mesothelioma in Hong Kong, 1988 to May 2002. The authors identified 67 patients (54 men, 13 women) through 12 of 20 public hospitals. These covered about 73% of the 20 hospitals' bed-years. Assuming a population of 5 million, estimated annual incidence was about one per million. Of 43 patients with occupational histories, 32 had occupational asbestos exposure; 22 of those 32 had worked in ships or dockyards. In 22 patients with data, all ship or dockyard workers, mean latency from first exposure to diagnosis was 46 years. Detailed analysis covered 48 patients with accessible records, compared with 67 occupational asbestosis patients. Median survival for mesothelioma patients was 9.5 months (95% confidence interval 6.3 to 12.7 months), and survival status could not be ascertained for 14 patients. Pleural plaques were found in 9 of 48 (18.8%) mesothelioma versus 53 of 67 (79.1%) asbestosis patients. This negative association remained significant after controlling for pleural effusion. The authors noted limits from the retrospective design and missing data. They concluded that a mesothelioma epidemic may occur in the 2010s without effective occupational asbestos control measures.

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 review of hospital medical records (case series), with mesothelioma patients compared against an external group of occupational asbestosis patients
• Who was studied: 67 malignant mesothelioma patients (54 men, 13 women) identified from 12 of 20 public hospitals in Hong Kong, 1988 to May 2002. Private hospitals were excluded. Detailed analysis used 48 patients with accessible medical records, all Chinese. The comparison group was 67 asbestosis cases confirmed by the Pneumoconiosis Medical Board from 1986 to the end of 2000.
• Exposure: Occupational asbestos exposure, taken from recorded occupational histories, mainly work in ships or dockyards, plus construction or demolition and other jobs. Fiber types were not specified for the patients. The authors also described Hong Kong asbestos consumption trends.
• Main results:
  • Estimated overall annual incidence of mesothelioma in Hong Kong, 1988 to 2002, was approximately one per million, assuming an average population of 5 million. In their summary the authors described this as at least one case per million per year.
  • Of the 32 mesothelioma patients with occupational asbestos exposure, 22 (68.8%) had worked in ships or dockyards. Four (12.5%) worked in construction or demolition and six (18.8%) had other jobs.
  • Eleven mesothelioma patients had no history of occupational asbestos exposure.
  • In 22 patients with available data, all of whom had worked in ships or dockyards, mean latency was 46 years (SD 11 years) and median duration of exposure was 18 years.
  • Mean age at diagnosis among the 48 mesothelioma patients with accessible records was 63.2 years (SD 15.4).
  • Pleural involvement was present in 43 of 48 patients (89.6%). Five (10.4%) had disease of the peritoneum only.
  • Histological type among the 48 patients was epithelioid in 22 (45.8%), sarcomatoid in 4 (8.3%), biphasic in 10 (20.8%) and unspecified in 12 (25%).
  • Median survival of mesothelioma patients was 9.5 months (95% confidence interval 6.3 to 12.7 months).
  • Survival status could not be ascertained for 14 mesothelioma patients.
  • By 3 years after diagnosis, 31 of 48 mesothelioma patients (64.6%) and 22 of 67 asbestosis patients (32.8%) had died. Survival was significantly worse for the mesothelioma patients.
  • Pleural plaques were present in 9 of 48 mesothelioma patients (18.8%) versus 53 of 67 asbestosis patients (79.1%), odds ratio 0.06 (95% CI 0.02 to 0.16). This negative association remained significant after controlling for pleural effusion.
  • Asbestos bodies were identified in 6 of 48 mesothelioma patients (12.5%) versus 19 of 67 asbestosis patients (28.4%), odds ratio 0.36 (95% CI 0.13 to 0.99).
  • Women made up 10 of 48 mesothelioma patients (20.8%) versus 1 of 67 asbestosis patients (1.5%), odds ratio 17.4 (95% CI 2.1 to 141.0). This association became non-significant after controlling for smoking history.
  • Annual consumption of asbestos cement articles in Hong Kong peaked around 11,500,000 kg in the early 1980s, declined for a decade, then rose again to around 7,500,000 kg in the late 1990s.
• The authors' conclusion: The authors concluded that the epidemiology of mesothelioma in Hong Kong is similar to the literature. They predicted that an epidemic of mesothelioma paralleling the 1990s surge in asbestos consumption may occur in the 2010s if effective occupational asbestos control measures are not in place.
• Limitations the authors state:
  • The authors stated that validity may be limited by the retrospective design and missing data. For example, 19 of 67 patients' records were not accessible, and survival status could not be ascertained for 14 patients.

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Mesothelioma, Epidemiology, Occupational History, Asbestos Exposure, Latency, Median Survival, Epithelioid.

Related studies

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• Asbestos fiber burdens in lung tissues of Hong Kong Chinese with and without lung cancer — Y. Liu, P. Zhang, et al. (2001)
• History of Asbestos Ban in Hong Kong — C.K. Wong, S.H. Wan, et al. (2017)
• Surgery for invasive primary mediastinal tumors — E.A. Bacha, A.R. Chapelier, et al. (1998)
• Chest CT combined with artificial pneumothorax: value in determining origin and extent of tumor — A. Watanabe, K. Shimokata, et al. (1991)

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