HealthDay News — Occupational exposure to solvents before first full-term birth may be associated with an increased risk of breast cancer in certain settings, according to researchers.
“Solvents such as benzene and trichloroethylene have been recognized by the International Agency for Research on Cancer and the U.S. National Toxicology Program as known human carcinogens; however, there are limited data on solvents as human breast carcinogens,” wrote Christine C. Ekenga, MPH, PhD, and colleagues in Cancer Research.
Researchers examined the correlation between occupational exposure to solvents and breast cancer in a prospective study involving 47,661 women from the Sister Study cohort. Occupational solvent exposure was classified according to baseline data relating to self-reported job-specific solvent use.
During follow-up, 1,798 women received a diagnosis of breast cancer, including 1,255 invasive incidences. Inspectors observed no correlation between the risk of invasive breast cancer and lifelong exposure to solvents (hazard ratio: 1.05; 95% CI: 0.88-1.24).
The risk of estrogen receptor-positive invasive breast cancer was increased for parous women who worked with solvents before the first full-term birth, compared with women who never worked with solvents (HR, 1.39; 95% CI: 1.03-1.86). Among clinical laboratory technologists and technicians, there was an increased risk of estrogen receptor-positive invasive breast cancer associated with solvent exposure (HR, 2.00; 95% CI: 1.07-3.73).
“Our results suggest that occupational exposure to solvents before first full-term birth is associated with an increased risk of breast cancer,” the investigators noted. “Further large-scale epidemiologic studies are warranted to explore the relationship between the timing of occupational chemical exposures and breast cancer incidence.”