The Proportion of Occupationally Related Cholangiocarcinoma: A Tertiary Hospital Study in Northeastern Thailand

Our plain-English summary of The Proportion of Occupationally Related Cholangiocarcinoma: A Tertiary Hospital Study in Northeastern Thailand, by A. Seeherunwong, N. Chaiear, N. Khuntikeo, et al (Cancers, 2022).

The study

• Authors: A. Seeherunwong, N. Chaiear, N. Khuntikeo, C. Ekpanyaskul
• Journal: Cancers
• Published: 2022;14(10)
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Northeastern Thailand registers the highest worldwide incidence of cholangiocarcinoma (CCA). Most of the cases are associated with liver flukes, while unknown causes comprise approximately 10-30% of cases, and these could be due to occupational exposures. Our aim was to determine the magnitude of occupational causes of CCA in a tertiary hospital in northeastern Thailand. We conducted a cross-sectional study with a sample of 220 patients between March and November 2021. Descriptive statistics were used to analyze the findings. Clinical information and telephone interviews were used to explore significant occupational histories. An occupational consensus meeting was held with two occupational physicians, an industrial hygienist, and a hepatobiliary surgeon to decide on the final diagnosis. The response rate was 90.9% (200/220). Based on the medical records and telephone interviews, researchers found that 11 participants had significant exposure. After occupational consensus, it was agreed that the eleven had possible occupational causes, 5.5% (11/200)-54.5% (6/11) being due to asbestos fibers, 45.5% (5/11) due to dichloromethane, and 9.1% (1/11) due to 1,2-dichloropropane. Only 4% (8/200) had occupational histories collected by their treating physicians. Taken together, occupationally related CCA appears to have been underestimated, so improving occupational history taking is needed to properly identify and classify work-related CCA-both for patient treatment and occupational hazard prevention.

In plain English

This cross-sectional descriptive study looked for possible work-related causes of cholangiocarcinoma (bile duct cancer) among patients at a tertiary hospital in northeastern Thailand. Patients aged 80 or younger without known high-risk liver or bile duct conditions or a family history of the cancer were eligible. Of 220, 200 completed telephone interviews about their work histories between March and November 2021. A panel of two occupational physicians, an industrial hygienist and a hepatobiliary surgeon reviewed those with significant exposure. Eleven of 200 patients (5.5%; 95% confidence interval 2.3 to 8.7%) were judged to have possible occupationally related cancer. Six were exposed to asbestos and five to dichloromethane, one of whom was also exposed to 1,2-dichloropropane. The six asbestos-exposed men were three roofing workers, two construction workers and a road worker, with a mean of 35.5 years of exposure. Five of the six had intrahepatic cancer. Treating physicians had recorded a work history for only 8 of 200 patients. The authors concluded that occupationally related cholangiocarcinoma had been underestimated because work histories were rarely taken. They noted the study had no comparison group, a small sample, and possible underestimation from incomplete recall.

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: Cross-sectional descriptive study using telephone interviews and hospital medical records, with a multidisciplinary consensus meeting (two occupational physicians, an industrial hygienist and a hepatobiliary surgeon) to classify possible occupationally related cases
• Who was studied: Patients with cholangiocarcinoma at a tertiary hospital in northeastern Thailand, aged 80 or younger, without high-risk conditions (such as primary sclerosing cholangitis, cirrhosis, hepatitis B or C, biliary stones) or a family history of cholangiocarcinoma. 220 eligible persons were drawn from a target population of 293, and 200 responded. Data were collected March to November 2021.
• Exposure: Occupational exposure to asbestos (fiber type not specified), dichloromethane and 1,2-dichloropropane. Significant exposure required inappropriate use of protective equipment together with more than 6.1 work years of dichloromethane or 1,2-dichloropropane exposure, or asbestos exposure at work for more than 30 consecutive days per year for 30 years. Asbestos jobs included roofing and roof demolition, road work cutting and drilling cement sheets, and construction work with asbestos-based building products.
• Main results:
  • 200 of 220 eligible patients (90.9%) responded to the telephone interview
  • 11 of 200 patients (5.5%; 95% CI 2.3 to 8.7) had significant occupational exposure. All 11 were classified by the consensus team as possible occupationally related cholangiocarcinoma.
  • Among the 11 cases, 6 (54.5%) were exposed to asbestos, 5 (45.5%) to dichloromethane and 1 (9.1%) to 1,2-dichloropropane. The 1,2-dichloropropane case was also exposed to dichloromethane.
  • In the case table, the six asbestos-exposed men were listed as three roofing workers (roofing and roof demolition), two construction workers (one of whom also did roofing) and one road worker. The text describes the majority as roof workers.
  • Mean duration of exposure was 19.4 years (SD 15.1, range 10 to 40) in the dichloromethane or 1,2-dichloropropane group and 35.5 years in the asbestos group
  • Mean latency to cholangiocarcinoma in the asbestos group was 36.5 years (SD 3.6; range 34 to 43)
  • 5 of the 6 asbestos-exposed cases (83.3%) had intrahepatic cholangiocarcinoma
  • All 11 possible occupational cases were male; 9 had smoked and 8 had consumed alcohol
  • Treating physicians had recorded an occupational history for only 8 of 200 participants (4%)
• The authors' conclusion: The authors concluded that 5.5% of the 200 patients had potentially occupationally related cholangiocarcinoma. They concluded that such cases were underestimated because treating physicians rarely took occupational histories, and that confirmatory research is needed given the small sample.
• Limitations the authors state:
  • No control group to confirm the strength of the relationship between exposed and non-exposed participants
  • Small sample size that does not allow generalization of findings
  • Possible underestimation of occupationally related cases due to incomplete recall in retrospective assessment
  • Liver fluke infection data from feces and urine tests in medical records might not give a precise diagnosis
  • No information on dose and duration of cigarette smoking and alcohol consumption
  • Cumulative exposure could not be calculated for individuals

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Treating Physician, Occupational History.

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• IgG4-related lung disease in a worker occupationally exposed to asbestos — M. Toyoshima, K. Chida, et al. (2010)
• CYP1A1 and CYP1B1 polymorphisms as modifying factors in patients with pneumoconiosis and occupationally related tumours: A pilot study — J. Schneider, U. Bernges (2009)

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