Exposure to Occupational Contaminants and Risk of Male Breast Cancer: A European Case-Control Study

Abstract

P-171 Abstract: Several environmental exposures have been suspected to play a role in breast cancer etiology, including organochlorine pesticides or other endocrine disrupting chemicals, polycyclic aromatic hydrocarbons (PAHs), and organic solvents, but epidemiological studies of breast cancer have produced inconsistent results. Exposure to these contaminants may also take place in occupational settings. Although male breast cancer is a rare disease, the study of breast cancers in males offers several advantages over a study of breast cancer in females because occupational exposures are usually much higher, and hence more easily assessed in men than in women, and because confounding or effect modification from reproductive risk factors cannot occur. We investigated occupational risk factors for male breast cancer in a European multicenter population-based case-control study that permitted to identify a relatively large numbers of cases. The study included 104 cases of male breast cancer aged 35 to 70 years and 2106 controls in eight European countries. Controls were selected from population registers in all countries, with the exception of Spain and Portugal where colon cancer controls only were available. All study subjects were interviewed across Europe using the same structured questionnaire that included a detailed work history. Occupational exposures to pesticides, PCBs, PAHs, alkylphenols, bisphenol-A, and phthalates were identified through a job-exposure matrix and then individually assessed by an expert using the detailed job description. A job-exposure matrix for petroleum solvents (e.g., benzene, white spirit) is also used. Analyses are carried out to identify the job groups at increased risk for male breast cancer and to examine breast cancer risk according to exposure indicators for specific chemicals. A statistically significant increased risk was observed in printers (OR=2.8 95%CI), painters (OR=2.5 95%CI 1.1–5.7), foundry workers (OR=4.6 95% CI 1.3–17.0), and motor vehicle mechanics (OR=2.0 95% CI 1.1–4.8). Workers in these occupational groups may have been exposed to suspected carcinogens for breast cancer, including organic solvents, gasoline, PAHs and combustion products. Confounding from other risk factors for male breast cancer such as alcohol drinking could not explain these results. The analyses for the specific occupational exposures will permit to further scrutinize these findings. Our results confirm that environmental factors may play a role in breast cancer, and suggest that additional studies on environmental factors in female breast cancer should be conducted.