Cancer 2
Tuesday 7 October 2025, 11.00 – 12.30 Flash
Chairs: Mary Schubauer-Berigan, Sylvia Jochems
Beyond multiplicity: Strategies for assessing work-related risks in the surveillance of occupational cancers in Italy
Giorgia Stoppa (presenter)
Annibale Biggeri , Claudio Gariazzo , Stefania Massari , Dolores Catelan
Abstract
Objective To enhance the interpretation of occupational cancer risks within the BEST project (“Big data and deep learning for the surveillance of occupational cancers”) by applying statistical methods that address multiple and selective inference, improving the prioritization of work sectors and cancer sites.
Material and Methods Mortality data from the Italian National Statistics Institute (2005–2018) were linked to employment histories from the National Social Insurance Agency (1974–2018). Each individual was assigned the sector with the longest employment duration as a proxy for occupational exposure, applying a minimum latency of five years. Cancer Mortality Odds Ratios (CMORs) were estimated by cancer site and employment sector, adjusting for age, place of residence, year of death, and education level. Analyses were stratified by sex and occupational class, using the service sector as the reference. To address multiplicity and selective inference, synthesis methods included QQ-plots with guide rails, control of the Positive False Discovery Rate (q-values), and multivariate hierarchical Bayesian models for rank estimation and uncertainty quantification. These approaches allowed the generation of league tables of sector rankings with credibility intervals. This study is funded by the Italian Workers’ Compensation Authority (contract ID 56/2022), within the framework of the BEST project.
Results In male blue-collar workers, CMORs were computed for 43 sectors and 10 cancer sites. Lung cancer showed excess mortality in transport and construction and a deficit in agriculture; highlighted heterogeneity across sectors. Additional sector-site differences emerged from q-value analyses. Bayesian rankings placed lung cancer in construction consistently at the top, with narrow 80% credibility intervals.
Conclusion Rigorous synthesis methods that address multiplicity and selective reporting improve the interpretation of occupational cancer risks. Graphical and Bayesian approaches offer robust tools for identifying priority sectors and support evidence-based surveillance strategies.
Cancer, chronic obstructive pulmonary disease, and ischemic heart disease in Ontario, Canada workers exposed to diesel engine exhaust
Stephanie Ziembicki (presenter)
Tracy L Kirkham, Victoria H Arrandale, Tanya Navaneelan, Paul A Demers
Abstract
Objective Diesel engine exhaust (DEE) is a common occupational exposure associated with lung and bladder cancers and chronic respiratory and cardiovascular diseases. The association between DEE and lung cancer is well-established, but the relationship with other health outcomes is less understood. This study assesses potential dose-response relationships for lung and bladder cancers, chronic obstructive pulmonary disease (COPD), and ischemic heart disease (IHD) in Ontario workers exposed to DEE in the Occupational Disease Surveillance System (ODSS) using a new job-exposure matrix, the Diesel Exhaust in Canada Job-Exposure Matrix (DEC-JEM).
Methods The ODSS includes ~2.2 million workers identified through workers’ compensation claims (1983-2019). Workers were followed for cancer through linkage with the Ontario Cancer Registry (1983-2020). For COPD and IHD, the Discharge Abstract Database (2006-2020), National Ambulatory Care Reporting System (2006-2020), and Ontario Health Insurance Plan (1999-2020) were used. Exposure was assessed using DEC-JEM, a semi-quantitative job-exposure matrix based on expert assessment and published exposure data of measurements of elemental carbon. Cox-proportional hazards models were used to estimate hazard ratios and 95% confidence intervals, adjusted for age, birth year, and sex.
Results Overall, 24,958 incident lung cancer, 8788 bladder cancer, 47,503 COPD, and 261,593 IHD cases were identified. Among exposed cases (all outcomes), the majority (90%) were assigned low exposure. Statistically significant increased risks of lung cancer (33%), bladder cancer (22%), COPD (33%), and IHD (15%) were observed among exposed workers compared to unexposed workers. Risk for all outcomes was notably higher among the high/very high group. The risk for females was generally higher than males, except for IHD. There was an increased risk for all diseases in transportation, manufacturing, and construction.
Conclusion This study improved understanding of DEE health effects and could potentially improve workers compensation practices. Targeted prevention resources could reduce DEE exposure and occupational disease risk.
Joint effects of occupational exposure to asbestos or respirable crystalline silica and tobacco smoking on lung cancer risk
Wendy Bijoux (presenter)
Florence Guida, Abdoulaye Barry, Barbara Charbotel, Liacine Bouaoun, Ann Olsson, and the SYNERGY study group
Abstract
Objective To explore joint effects of occupational exposure to asbestos and respirable crystalline silica (RCS) and smoking on lung-cancer risk.
Material and Methods This analysis in men included 13,605 lung-cancer cases and 16,451 controls from 14 European and Canadian case-control studies. Job histories were linked to SYN-JEM to assign occupational exposure to asbestos and RCS. Various metrics of smoking and occupational exposure to asbestos and RCS were investigated in relation to lung cancer risk using unconditional logistic regression models. Odds ratios (ORs) and 95% confidence intervals (CIs) were adjusted for study centre, age group, and “recognized high-risk occupations”. Joint effects were evaluated on the additive scale by calculating the relative excess risk due to interaction (RERI) and corresponding 95% CI using the delta-method.
Results Occupational cumulative exposure to asbestos median have a RERI: 1.67, CI 1.06 to 2.29. Cumulative asbestos exposure results in positive RERIs, whether median (RERI: 3.70, CI 2.31 to 5.08), with cumulative smoking >20py. Occupational cumulative exposure to RCS median. When RCS median with smoking >20py.
Conclusion Occupational exposure to RCS and smoking confers an excess lung-cancer risk beyond additivity even at cumulative exposure levels below median and light smoking. Occupational exposure to asbestos and smoking shows a similar pattern, except a small RERI at cumulative exposure to asbestos below median and light smoking. These findings emphasize the need for proactive control of occupational exposures and prevention of tobacco smoking.
Joint effects of occupational exposure to hexavalent chromium and tobacco smoking on lung cancer risk
Abdoulaye Barry (presenter)
Florence Guida, Barbara Charbotel, Liacine Bouaoun, Wendy Bijoux, Ann Olsson and the SYNERGY study group
Abstract
Objective To provide refined information on joint effects of occupational exposure to hexavalent chromium (Cr(VI)) and smoking on lung-cancer risk.
Material and Methods This analysis in men included 13,605 lung-cancer cases and 16,451 controls from 14 European and Canadian case-control studies. Job histories were linked to the SYN-JEM assigning occupational exposure to Cr(VI). Various smoking-related metrics and ever/never occupational exposure to Cr(VI) were investigated in relation to lung cancer risk using unconditional logistic regression. Odds ratios (ORs) and 95 % confidence intervals (CIs) were adjusted for study centre, age group, and recognized high-risk occupations. Joint effects were evaluated on the additive scale by calculating the relative excess risk due to interaction (RERI) and corresponding 95% CIs using the delta-method.
Results Ever occupational exposure to Cr(VI) occurred in 30 % of cases and 23 % of controls. Light and moderate smokers (<20 cigarettes/day) showed OR 13.4, CI 11.9–15.1 not exposed to Cr(VI) and OR 17.4, CI 15.2–20.0 with exposure to Cr(VI), with RERI 3.79, CI 2.12–5.47. Heavy smokers (≥20 cigarettes/day) not exposed to Cr(VI) had OR 27.6, CI 24.2–31.6 and with Cr(VI) OR 33.6, CI 28.3–39.9; with RERI 5.72, CI 0.79–10.66. In recent quitters of smoking (1-15 years), the OR was 9.15, CI 8.09–10.4 when not exposed to Cr(VI) and with exposure to Cr(VI) OR 10.8, CI 9.35–12.50 with RERI 1.44, CI 0.20–2.67. After 15 years of smoking cessation, the joint effect was weakened, with a RERI of 0.35, CI -0.16–0.85.
Conclusion Occupational Cr(VI) exposure augments smoking-related lung-cancer risk beyond additivity. The RERI remains elevated for up to 15 years after tobacco cessation. These results support integrated control of workplace exposure to Cr(VI) and tobacco control.
Mortality and cancer incidence in a large cohort of lead-exposed workers
Kyle Steenland (presenter)
Youran Tan; Kaitlin Kelly-Reif
Abstract
Introduction. Lead is a common occupational exposure, a suspected carcinogen (IARC group 2A), and associated with several other chronic diseases. Here we analyze mortality and cancer incidence in a large cohort of US workers with blood lead levels based on data from the National Institute for Occupational Safety and Health (NIOSH).
Methods. We updated mortality follow-up for a cohort of 58,000 male lead-exposed workers through 2021. We followed a subset of 37,000 of these workers for cancer incidence through 2021. Internal exposure-response analyses used highest recorded blood lead as the exposure.
Results. In the cohort, the median birth year was 1959, and the average year of first blood test was 1997. Mean highest blood lead was 26 ug/dl, compared to current US general population levels of 3 ug/dl. There were 8,832 deaths. Mortality results showed positive significant trends of lung cancer, pancreatic cancer, heart disease, chronic obstructive pulmonary disease, and chronic renal disease, with increased blood lead levels. Among the subset of 37,000 workers, there were 5,832 incident cancers. Among them, only lung cancer showed a significant positive trend; brain and liver cancer showed borderline significant positive trends (p-values between 0.05 and 0.10). Thyroid and prostate cancer showed significant negative trends. While lung cancer trends might be related to smoking, there is no a priori reason why workers with higher blood lead would have smoked more, and in a subset of 200 workers with smoking data there was no such evidence. Lung cancer rate ratios on the order of 2.0-2.5 are also unlikely to be explained by smoking differences.
Conclusion. In this large cohort with documented blood lead levels, higher lead was associated with several causes of mortality and cancer incidence.
Occupational exposure to chromium(VI) and five selected cancer sites: systematic review and meta-analyses
Jan-Paul Zock (presenter)
Kelly J. Rijs, Susan Peters, Jelle J. Vlaanderen
Abstract
Objective: Hexavalent chromium (Cr(VI)) is a human carcinogen. It is unclear whether Cr(VI) can cause cancer of the small intestine, oral cavity, pancreas, prostate and urinary bladder. We performed a systematic review and meta-analyses of epidemiological studies on occupational exposure to Cr(VI) and incidence and mortality of these cancer sites.
Material and Methods: A comprehensive review of human studies on Cr(VI) and cancer was performed in Embase and Scopus. 131 potentially relevant epidemiological studies were identified. Study quality was assessed using Newcastle-Ottawa Scale. 29 publications including 81 observations for meta-analyses were based on cohort or case-control studies with exposure assessment of sufficient quality. Site-specific random-effects meta-analyses were done separately for incidence and mortality. Sensitivity analyses focused on the studies with the highest quality scores.
Results: No indications for an association between Cr(VI) exposure and oral or small intestine cancer were found. Incidence of pancreatic cancer was not associated with Cr(VI) exposure (meta-RR 1.04; 95%CI 0.85-1.28) while for specific mortality RR was 1.41 (0.96-2.08) with moderate heterogeneity (I2=41%) and an asymmetric funnel plot (Egger’s test; p=0.002). For incidence of prostate cancer meta RR was 1.16 (0.99-1.37) while the RR for mortality was 1.03 (0.84-1.25). For bladder cancer, RR was 1.04 (0.91-1.20) for incidence and 1.76 (1.20-2.60) for mortality.
Conclusion: There are indications that pancreas, prostate and bladder cancer may be related to occupational exposure to Cr(VI) compounds, but in the meta-analyses sufficient evidence was not provided. For oral cavity and small intestine cancer, reported indications from animal models were not supported by human studies.