Benzene and Lung Cancer Risk
According to a study published in the American Journal of Respiratory and Critical Care Medicine, being exposed to benzene during work heightened the odds of lung cancer development. Over the last several decades benzene has been regulated extensively. The result is exposure to benzene has declined to 1 ppm among most occupational groups in North America and Europe. Benzene is still problematic though because people can be exposed at unregulated workplaces and low- and middle-income countries. Using a pooled analysis of 14 case-control studies, researchers assessed 12,329 individuals with lung cancer and 15,719 individuals without lung cancer to see how occupational benzene exposure is linked to lung cancer risk.
Researchers estimated the amount of benzene exposure with a quantitative job-exposure matrix. In the group of patients with lung cancer, there were 5,838 individuals that had exposure to benzene while the remaining 6,491 individuals did not have exposure to benzene. The control group, which consisted of individuals without lung cancer, included 6,253 exposed individuals and 9,466 unexposed individuals. In the exposed population, the three occupations with the highest exposure levels included “painter and related workers,” “varnishes and related painters,” and “shoemakers and related workers.” With an adjustment for study, age group, sex, smoking and occupational lung carcinogens of asbestos, hexavalent chromium, polycyclic aromatic hydrocarbons, silica, and diesel engine exhaust, researchers were able to observe elevated odds for lung cancer among ever vs never exposed individuals. More specifically people exposed to more than 5 ppm of benzene exposure per year vs those without exposure had greater odds of lung cancer.
Individuals in the lowest cumulative exposure group (> 0 ppm to 1 ppm of benzene a year) had a higher likelihood for lung cancer than individuals unexposed to benzene. Both exposure length and length of time since exposure impacted the odds of lung cancer. As exposure length increased, so did the likelihood of getting lung cancer. Individuals with one to nine years of exposure and 10 to 19 years of exposure faced heightened odds of lung cancer. The likelihood of getting lung cancer gradually decreased as more time passed since being exposed to benzene. Those with five years since last exposure had a high odds ratio of 1.43, but this went down in each time group including five to nine years since exposure, 20 to 29 years since exposure, and more than 39 years since exposure group.
In the exposed to benzene group, individuals had heightened odds of four different types of lung cancer including adenocarcinoma, squamous cell carcinoma, small cell carcinoma, and large cell carcinoma. The odds for each subtype were similar to the overall odds of getting lung cancer. The only cancer with a decreasing trend in lung cancer odds as time passed since benzene exposure was squamous cell carcinoma.
It was also found that benzene exposure while working raised the risk of lung cancer in former smokers, current smokers, and never smokers. Never smokers with more than 5 ppm of benzene exposure a year vs no exposure had a higher likelihood for lung cancer, but this went down in the lowest cumulative exposure group.
Researchers also found similar patterns to the main analysis when assessing the odds for lung cancer in never smokers based on exposure length and time since last exposure. Specific occupational groups, exposures, and studies did not influence the main findings. The researchers found that occupational benzene exposure increased lung cancer risk and they want to study if benzene exposure actually causes lung cancer.
Were you exposed to benzene and later diagnosed with cancer? Contact us today at 412-471-3980 or fill out our contact form and a member of our team will get back to you as soon as possible.
