Occupational exposure to specific organic solvents and risk of subtypes of breast cancer in a large population of Danish women, 1964–2016
Menée à partir des données du registre danois des cancers portant sur 38 375 patientes atteintes d'un cancer du sein (âge : moins de 70 ans), cette étude analyse l'association entre une exposition professionnelle à 4 solvants organiques (méthylchloroforme, trichloréthylène, benzène et toluène) et le risque de développer la maladie
Objective: To explore associations between occupational exposure to four specific organic solvents, respectively, and female breast cancer, including subtypes. Methods: Using the Danish Cancer Registry, we identified 38 375 women under age 70 years with primary breast cancer. Five randomly selected breast-cancer-free controls per case matched on year of birth were retrieved from the Danish Civil Registration System . A nationwide pension fund was used to retrieve full employment history, and exposure to 1,1,1-trichloroethane, trichloroethylene (TCE), benzene and toluene was assessed using a job exposure matrix. ORs were estimated using conditional logistic regression with adjustment for reproductive factors and socioeconomic status. Results: Overall results indicated no noteworthy associations between the specific organic solvents and breast cancer before and after age 50 years, except for a small increased risk after age 50 in women exposed to TCE (OR=1.15, 95% CI: 0.97–1.36). After age 50 years, exposure to TCE was associated with a small increased risk in women with over 20 years of latency (OR=1.26, 95% CI: 1.02–1.56). Further, an increased risk of oestrogen receptor positive (ER+) tumours was also observed (OR=1.21, 95% CI: 1.01–1.47), and high cumulative exposure and longer latency also increased the risk of this subtype. Conclusion: This study provides limited evidence supporting the association between occupational exposure to each of the four organic solvents and breast cancer. The risk of ER+ breast tumours after age 50 years may be increased in women with TCE exposure, and this possible association therefore needs further attention in future studies.