Cumulative occupational exposure to organic solvents is associated with an increased risk for bladder cancer, according to data presented at the American Urological Association’s 2023 annual meeting in Chicago, Illinois.

A team led by Stella Koutros, PhD, MPH, of the Occupational and Environmental Epidemiology Branch at the National Cancer Institute in Bethesda, Maryland, evaluated exposure to 21 individual solvents and its effect on bladder cancer risk in a study that compared 1182 patients with incident bladder cancer and a control group of 1408 individuals from a population-based study.

Individuals in the second, third, and fourth quartile of cumulative benzene-toluene-zylene exposure had significant 1.5-, 1.9-, and 2.2-fold increased odds of being diagnosed with bladder cancer compared with unexposed individuals after adjusting for age, race/ethnicity, sex, and other potential confounders, Dr Koutros reported in a slide presentation during a virtual press session at the conference.

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The study is the first to document an increased risk of bladder cancer associated with cumulative exposure to benzene-toluene-zylene. Occupations involving exposure to benzene-toluene-zylene include automobile mechanics, automotive body repairers, painters, and shoe machine operators, according to the investigators.

Although bladder cancer has been linked to several occupations that involve the use of solvents, only perchloroethylene, which is used in dry cleaning, is classified as probably carcinogenic to human beings, the investigators noted. The risk posed by other commonly used solvents remains unclear.

The authors noted that benzene-toluene-zylene exposure is not limited to occupations that involve use of these solvents. Exposure can occur in the general environment from industrial emissions, tobacco smoke, gas stations, and motor vehicle exhaust.

“The current study expands our understanding of what professions are at higher risk for bladder cancer and may need more thorough evaluation,” said press session moderator Martha K. Terris, MD, Witherington Distinguished Professor of Urology and Chair of the Section of Urology at the Medical College of Georgia in Augusta.

Dr Terris noted that American Urological Association guidelines stratify patients with hematuria into risk categories to indicate how extensive an evaluation is required.


Xie S, Friesen M, Barus D, et al. Occupational exposure to organic solvents and risk of bladder cancer. Presented at: AUA 2023, April 28-May 1, Chicago, Illinois. Abstract MP22-13.