Bladder cancer rates rising in most occupations exposed to carcinogens: Review

NEW YORK (Reuters Health) — Bladder cancer rates are rising, especially among women, and occupational exposure to carcinogens may be responsible, according to a meta-analysis.

"Occupational bladder cancer is a current problem and not a historical issue," James Catto from the Medical School, University of Sheffield, Sheffield, England, told Reuters Health by email.

In the 1980s, an estimated 10 per cent of bladder cancers arose from occupational exposure. Workplace legislation should have reduced this rate, but whether this is the case remains to be seen, according to the researchers.

Catto's team investigated whether social and workplace legislative changes have altered the risk for bladder cancer through their systematic review and meta-analysis of 263 contemporary reports of occupational exposure and bladder carcinogenesis in 1,254 occupations.

Compared with the general population, bladder cancer incidence rates were 16.6 times higher for factory workers, 13.4 times higher for hairdressers, and 11.8 times higher for aircraft/ship's officers. Bladder cancer mortality rates were 27.1 times higher for chemical workers and 8.3 times higher for dye workers.

There was a steady decline in standardized incidence ratios (SIRs) between the 1960s and 1980s for both sexes, but the trend reversed in the 1980s and in the first decade of the 21st century the SIR increased to 1.13 for men and 1.27 for women.

SIRs were higher for women than for men, but standardized mortality ratios (SMRs) were higher for men than for women, according to the Oct. 8 JAMA Oncology online report.

The incidence of bladder cancer increased in 42 of 61 (67 per cent) and decreased in 6 of 61 (10 per cent) occupational classes. The highest risks were for workers exposed to aromatic amines (tobacco, dye, and rubber workers; hairdressers; printers; and leather workers) and polycyclic aromatic hydrocarbons (PAHs) (chimney sweeps, nurses and waiters, aluminum workers, seamen, and oil/petroleum workers).

Agricultural sector workers had the lowest occupational bladder cancer risk.

The highest bladder cancer mortality rates occurred in workers exposed to heavy metals and PAHs and those exposed to aromatic amines.

Exposures included 44 agents with a reported role in urothelial carcinogenesis.

"While there have been reductions in occupational bladder cancer incidence and mortality, it appears that there may still be many occupations with an elevated incidence or mortality risk," the researchers concluded. "This persists despite improvements in workplace hygiene, although the profile of at-risk occupations has changed over time and may differ for bladder cancer incidence and mortality. Efforts to reduce the impact of bladder cancer on workers should be targeted to occupations at risk of mortality."

Catto recommended educating staff on the symptoms of bladder cancer, as well as  workplace safety, such as knowledge of diesel fume harm, secondhand tobacco smoke inhalation, or the use of carcinogenic agents in other industries.