Asbestos exposure as an additional risk factor for small duct intrahepatic cholangiocarcinoma: a pilot study

Our plain-English summary of Asbestos exposure as an additional risk factor for small duct intrahepatic cholangiocarcinoma: a pilot study, by F. Vasuri, M. Deserti, A.G. Corradini, et al (Scientific Reports, 2023).

The study

• Authors: F. Vasuri, M. Deserti, A.G. Corradini, S. Tavolari, V. Relli, A. Palloni, G. Frega, S. Curti, S. Mattioli, M. Cescon, A. D'Errico, G. Brandi
• Journal: Scientific Reports
• Published: 2023;13(1):2580
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Intrahepatic cholangiocarcinoma (iCCA) is a rare malignancy, recently classified in small duct and large duct morphological subtypes. Growing evidence suggests asbestos as a putative risk factor for iCCA, albeit no correlation between asbestos and iCCA morphology has been investigated so far. The aim of the present study was to assess the relationship between asbestos exposure and iCCA morphological subtype. Forty patients with surgically removed iCCA were prospectively enrolled: asbestos exposure was assessed according to the Italian National Mesothelioma Register questionnaire. From the surgical iCCA specimens the main histopathological variables were collected, including the small duct (sd-iCCA, 32 patients) and large duct subtypes (ld-iCCA, 8 patients). Five sd-iCCA cases had a definite/probable occupational exposure to asbestos, while no cases of ld-iCCA were classified as being occupationally exposed (definite/probable). Other kind of asbestos exposure (i.e. possible occupational, familial, environmental) were recorded in 16 sd-iCCA and 3 ld-iCCA. Cases with unlikely exposure to asbestos were 11 sd-iCCA (35.5%) and 5 ld-iCCA (62.5%). In conclusion, these findings seem to indicate that sd-iCCA might be more frequently associated to asbestos exposure rather than ld-iCCA, suggesting that asbestos fibres might represent a parenchymal, rather than a ductal risk factor for iCCA. This pilot study must be confirmed by further case-control studies or large independent cohorts.

© 2023. The Author(s).

In plain English

This pilot study, from a single hospital in Bologna, Italy, looked at 40 patients who had surgery for intrahepatic cholangiocarcinoma, a cancer of the bile ducts inside the liver. Pathologists sorted the tumors into two subtypes: small duct (32 patients) and large duct (8 patients). An occupational physician classified each patient's lifetime asbestos exposure from an interview questionnaire used by the Italian National Mesothelioma Register. The article does not name fiber types. All 5 patients with definite or probable occupational exposure had small duct tumors. Counting any exposure (occupational, environmental or familial), 21 of 32 small duct patients (65.6%) and 3 of 8 large duct patients (37.5%) were classed as exposed. This difference did not reach statistical significance (p = 0.229; odds ratio 3.2, 95% CI 0.6 to 15.9; adjusted odds ratio 3.4, 95% CI 0.6 to 93.7). The authors concluded that small duct tumors might be more often associated with asbestos exposure. They said the small sample size precluded causal conclusions and called for larger studies.

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: Pilot study within a single-centre prospective study (EtherBil), comparing asbestos exposure between two tumor subtypes
• Who was studied: 40 patients (18 males, 22 females; mean age at surgery 63.9 years, range 36 to 85) who had liver resection for histologically proven intrahepatic cholangiocarcinoma at one hospital in Bologna, Italy. 32 had small duct tumors and 8 had large duct tumors. Enrollment dates are not given.
• Exposure: Lifetime asbestos exposure, assessed by an occupational physician from a structured questionnaire (the Italian National Mesothelioma Register questionnaire) given to patients or their next of kin. It was classified as definite/probable occupational, possible occupational, environmental, familial, or unlikely. Fiber types and specific jobs are not reported. Mean exposure duration was 34.3 years (range 10 to 66), described as long exposures at low or very low fiber concentrations.
• Main results:
  • Of the 40 tumors, 32 (80.0%) were small duct subtype and 8 (20.0%) were large duct subtype.
  • All 5 patients with definite/probable occupational asbestos exposure had small duct tumors. None of the large duct patients were in this category.
  • Counting all exposure types (occupational, environmental, familial), 21 small duct patients (65.6%) and 3 large duct patients (37.5%) were exposed.
  • Exposure was classed as unlikely in 11 small duct patients (34.4%) and 5 large duct patients (62.5%). For exposed vs not exposed, p = 0.229 (Fisher's exact test) and odds ratio 3.2 (95% CI 0.6 to 15.9).
  • After adjustment for age, gender, alcohol drinking, smoking status and HBV/HCV chronic hepatitis, the odds ratio for being exposed to asbestos was 3.4 (95% CI 0.6 to 93.7) for small duct patients, with large duct patients as the reference.
  • No differences were found among the exposure groups in the other histopathological variables (data not shown).
• The authors' conclusion: The authors concluded that small duct intrahepatic cholangiocarcinoma might be more frequently associated with asbestos exposure than the large duct subtype. They suggested asbestos fibres might be a parenchymal (liver tissue) rather than a ductal risk factor, and said further case-control studies or large independent cohorts are needed to confirm this pilot study.
• Limitations the authors state:
  • The small sample size reduced statistical power and, the authors stated, precludes any causal conclusions, including from the adjusted analysis.
  • There are many risk factors for intrahepatic cholangiocarcinoma that are not related to asbestos.
  • Recall bias from using a questionnaire may have occurred and could have led to underestimating asbestos exposure among large duct patients.
  • Selection bias was considered possible, though the authors judged it unlikely to explain the difference because enrollment was prospective at a major referral centre.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Mesothelioma, Occupational Exposure.

Related studies

• Exposure to Asbestos and Increased Intrahepatic Cholangiocarcinoma Risk: Growing Evidences of a Putative Causal Link — G. Brandi, K. Straif, et al. (2022)
• Intrahepatic cholangiocarcinoma development in a patient with a novel BAP1 germline mutation and low exposure to asbestos — G. Brandi, M. Deserti, et al. (2020)
• New insights into the molecular pathogenesis of intrahepatic cholangiocarcinoma — T. Patel (2014)
• Asbestos and Intrahepatic Cholangiocarcinoma — G. Brandi, S. Tavolari (2020)
• Asbestos: a hidden player behind the cholangiocarcinoma increase? Findings from a case-control analysis — G. Brandi, S. Di Girolamo, et al. (2013)
• Occupational exposure to asbestos and risk of cholangiocarcinoma: a population-based case-control study in four Nordic countries — A. Farioli, K. Straif, et al. (2018)

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