MR imaging and MR cholangiopancreatography of cholangiocarcinoma developing in printing company workers

Mode of action assessment for propylene dichloride as a human carcinogen

As part of a systematic review of the non-cancer and cancer hazards of propylene dichloride (PDC), with a focus on potential carcinogenicity in workers following inhalation exposures, we determined that a mode of action (MOA)-centric framing of cancer effects was warranted. In our MOA analysis, we systematically reviewed the available mechanistic evidence for PDC-induced carcinogenesis, and we mapped biologically plausible MOA pathways and key events (KEs), as guided by the International Programme on Chemical Safety (IPCS)-MOA framework. For the identified pathways and KEs, biological concordance, essentiality of KEs, concordance of empirical observations among KEs, consistency, and analogy were evaluated. The results of this analysis indicate that multiple biologically plausible pathways may contribute to the cancer MOA for PDC, but that the relevant pathways vary by exposure route and level, tissue type, and species; further, more than one pathway may occur concurrently at high exposure levels. While several important data gaps exist, evidence from in vitro mechanistic studies, in vivo experimental animal studies, and ex vivo human tumor tissue analyses indicates that the predominant MOA pathway likely involves saturation of cytochrome p450 2E1 (CYP2E1)-glutathione (GSH) detoxification (molecular initiating event; MIE), accumulation of CYP2E1-oxidative metabolites, cytotoxicity, chronic tissue damage and inflammation, and ultimately tumor formation. Tumors may occur through several subsets of inflammatory KEs, including inflammation-induced aberrant expression of activation-induced cytidine deaminase (AID), which causes DNA strand breaks and mutations and can lead to tumors with a characteristic mutational signature found in occupational cholangiocarcinoma. Dose concordance analysis showed that low-dose mutagenicity (from any pathway) is not a driving MOA, and that prevention of target tissue damage and inflammation (associated with saturation of CYP2E1-GSH detoxification) is expected to also prevent the cascade of processes responsible for tumor formation.

The quantity and quality of scientific evidence about the health of working women in occupational health of Japan: A scoping review

OBJECTIVE

We aim to investigate the quantity and quality of scientific evidence dealing with comprehensive health issues of working women in occupational health.

METHODS

This scoping review of original articles that investigated comprehensive health issues of working women aged 19-64 years in Japan was published in PubMed (1967-2022) and Igaku Chuo Zasshi (or Ichu-shi, 1982-2022). Using identical broad search terms, we first identified 17 122 English and 6154 Japanese articles. We excluded those with clinically relevant topics, or ethnicity other than Japanese and included 853 English and 855 Japanese articles for review and classified them into nine research areas considered to be critical factors for women in the workforce and five study design groups to investigate the quality of the evidence accumulated.

RESULTS

Among 853 English-language articles in PubMed, "Mental health" was the most frequent area studied, followed by "Work-related disease" and "Lifestyle-related disease." Among 855 Japanese-language articles from Ichu-shi, "Mental health" was the most frequently studied area followed by "Work and balance," and "Work-related disease." "Infertility, pregnancy, and childbirth" and "Menstruation, menopause, and genital disease" were well studied in Ichu-shi but scarcely published in PubMed. "Harassment and discrimination" were sparsely reported in both databases. As for research designs, many articles in both PubMed and Ichu-shi employed descriptive or cross-sectional study designs. However, a few studies employed cohort/longitudinal or interventional studies.

CONCLUSION

The results underscored the need for higher-quality study designs with more scientific evidence on working women's health in the field of occupational health.

Multiple cholangiocarcinomas in the intrahepatic and extrahepatic biliary tree due to dichloromethane exposure: a case report

Background

An outbreak of cholangiocarcinoma in Japan has led to widespread concern among workers in printing plants. In March 2013, the Japanese Ministry of Health, Labour and Welfare, confirmed a causal relationship between cholangiocarcinoma and long-term exposure to dichloromethane (DCM) and 1,2-dichloropropane (DCP), which were widely used in printing plants. We herein report a rare case of successful radical resection of multiple cholangiocarcinomas in the intrahepatic and extrahepatic bile ducts caused by past exposure to DCM.

Case presentation

A 54-year-old man developed brown urine 22 years after his last exposure to DCP and DCM. He had an 11-year history of working at a printing plant from the age of 21 to 31 years and dealt with organic solvents during his employment. Enhanced computed tomography revealed a thickened distal bile duct wall with upstream biliary dilatation and multiple intrahepatic cholangiocarcinomas located in liver segments III, VI, and VIII. Biopsy of the distal bile duct wall revealed adenocarcinoma, and a diagnosis of distal cholangiocarcinoma was made. Tumor marker levels were within the reference range (carcinoembryonic antigen, 3.3 ng/mL; carbohydrate antigen 19-9, 25.4 U/mL; SPAN-1, 13 U/mL; and DUPAN-2, 33 U/mL). The multiple intrahepatic and extrahepatic bile duct cancers were treated by subtotal stomach-preserving pancreatoduodenectomy and partial hepatectomy of segments III, VI, and VIII. Pathological examination of the surgical specimens revealed multiple cholangiocarcinomas with well-differentiated adenocarcinoma in the biliary tree. The patient was still alive without recurrence 17 months after the operation.

Conclusions

We experienced a rare case of multiple cholangiocarcinomas in the intrahepatic and extrahepatic bile ducts that developed 22 years after the patient’s last exposure to DCP and DCM. Long-term and careful follow-up is required for workers with an occupational history of exposure to organic solvents because of the risk of development of cholangiocarcinoma.

Occupational cholangiocarcinoma diagnosed 18 years after the end of exposure to 1,2-dichloropropane and dichloromethane at a printing company: a case report

Background

Cholangiocarcinoma due to exposure to 1.2-dichloropropane (DCP) or dichloromethane (DCM) is classified as occupational cholangiocarcinoma. We report a case of occupational cholangiocarcinoma diagnosed 18 years after the end of exposure to organic solvents at a printing company.

Case presentation

A 41-year-old man presented to our hospital with jaundice and anorexia. He had previously worked for 6 years at a printing company where an outbreak of occupational cholangiocarcinoma occurred and was exposed to high concentrations of organic solvents during his employment. Computed tomography demonstrated lower bile duct obstruction by the bulky nodal metastasis at the hepatoduodenal ligament with upstream biliary dilatation, an intraductal papillary tumor in the dilated left superior lateral bile duct (B2), and enlargement of the periaortic nodes. Clinical diagnosis of an unresectable invasive intraductal papillary neoplasm of the bile duct (IPNB) with extensive nodal metastasis was made. Although chemotherapy and laparoscopic gastrojejunostomy were performed for the duodenal obstruction, the patient died due to rupture of the tumor. Pathological examination of the autopsy specimen revealed well-differentiated adenocarcinoma at the stromal site along Glisson’s sheath in segment 3, an IPNB lesion without invasion in B2, and biliary intraepithelial neoplasia and chronic bile duct injury at various sites in the large bile ducts. The bulky lymph node (poorly differentiated adenocarcinoma with partial squamous cell differentiation) invaded the bile duct and duodenum.

Conclusions

We report a case of occupational cholangiocarcinoma that developed 18 years after the end of exposure to DCP and DCM. Long-term follow-up is required to carefully survey development of cholangiocarcinoma in workers with an occupational history of exposure to organic solvents.

The Clinical Significance of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography in Patients with Occupational Cholangiocarcinoma

Objective

The present study aimed to identify the clinical significance of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging in patients with occupational cholangiocarcinoma.

Methods

This study included 10 men with occupational cholangiocarcinoma who were former or current workers at a printing company in Osaka, Japan. Of the 10 patients, 2 had 2 main tumors and 1 had 3 main tumors. Twelve FDG-PET imaging findings in the 10 patients could be analyzed. We evaluated the relationships between FDG-PET imaging parameters and clinicopathological findings of occupational cholangiocarcinoma.

Results

Abnormal FDG uptake was observed in 8 of the 14 main tumors, with maximum standardized uptake values ranging from 2.9 to 11.0, and the sensitivity was 57.1%. Four patients had lymph node metastases, and abnormal marrow uptake was detected in all these patients. Although precancerous lesions, such as biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the bile duct (IPNB) without any invasion, were not detected, abnormal FDG uptake was demonstrated in 2 of 4 patients with IPNB having an associated invasive carcinoma.

Conclusions

Although FDG-PET may be useful for assessing tumor progression factors, such as lymph node metastasis, it cannot accurately detect precancerous lesions, such as BilIN and IPNB without invasive carcinoma.

Occupational cholangiocarcinoma caused by exposure to 1,2-dichloropropane and/or dichloromethane

A cluster of cholangiocarcinoma among printing company workers who were exposed to 1,2-dichloropropane and/or dichloromethane was classified by the Ministry of Health, Labour and Welfare of Japan on 1 October 2013 as "occupational cholangiocarcinoma". At the time of the diagnosis of cholangiocarcinoma, levels of γ-glutamyl transferase, and aspartate and alanine aminotransferases were elevated, and had been elevated in some patients several years prior to the diagnosis. Regional dilatation of intrahepatic bile ducts without tumor-induced obstruction was characteristic in diagnostic imaging. Pathological examination found chronic bile duct injury with DNA damage, precancerous/preinvasive lesions such as biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct in various sites of the large bile ducts, and invasive cholangiocarcinoma such as mass-forming type and intraductal growth-type intrahepatic cholangiocarcinoma and mainly papillary-type extrahepatic cholangiocarcinoma. Whole-exome analysis of the cancerous tissues showed hypermutation, substantial strand bias, and unique trinucleotide mutational changes. Patients seemed to suffer high incidence of postoperative complications including intra-abdominal, which might be related to chronic bile duct injury. Postoperative recurrence from multicentric origins occurred in some patients, as DNA-injured bile ducts have high carcinogenic potential. Aggressive treatment, including second resections for such multicentric recurrences, appeared to be effective. In 2014, the International Agency for Research on Cancer classified 1,2-dichloropropane as Group 1 (carcinogenic to humans) and dichloromethane as Group 2A (probably carcinogenic to humans) carcinogens.