Abstract
Background: Ethylene oxide (ETO) is a sterilant gas considered to be a human carcinogen, due primarily to excess hematopoietic cancer in exposed cohorts. ETO causes mammary tumors in mice, and has been associated with breast cancer incidence in one small epidemiologic study. Methods: We have studied breast cancer incidence in a cohort of 7576 women employed for at least one year and exposed for an average 10.7 years while working in commercial sterilization facilities. Breast cancer incidence (n = 319) was ascertained via interview, death certificates, cancer registries, and medical records. Interviews were obtained for 68% of the cohort. Results: The standardized incidence ratio (SIR) for incident breast cancer in the whole cohort using external referent rates (SEER) was 0.87 (0.77–0.97). The SIR for those in the top quintile of cumulative exposure, with a 15 year lag, was 1.27 (0.94–1.69), with a positive trend of increasing SIR with increasing exposure (p = 0.002). SIRs are under-estimated because breast cancer incidence in the whole cohort was under-ascertained, due to incomplete response and lack of complete coverage by state cancer registries. In internal nested case–control analyses of those with interviews (complete cancer ascertainment), controlling for reproductive risk factors, a positive exposure–response was found with the log of cumulative exposure with a 15-year lag (p = 0.0005). The odds ratio by quintile of cumulative exposure were 1.00 (0 exposure due to 15 year lag), 1.06, 0.99, 1.24, 1.42, and 1.87. Conclusions: Our data suggest that ETO is associated with breast cancer, but a causal interpretation is weakened due to some inconsistencies in exposure–response trends and possible biases due to non-response and incomplete cancer ascertainment.
Similar content being viewed by others
References
NIOSH (1989) National Occupational Exposure Survey: sampling methodology. Cincinnati, OH: DHHS publication NIOSH, pp. 89-102.
IARC (1994) Some Industrial Chemicals, Monograph 60. Lyon, France: IARC.
Norman S, Berlin J, Soper K, Middendorf B, Stolley P (1995) Cancer incidence in a group of workers potentially exposed to ethylene oxide. Int J Epidemiol 24: 276-284.
Tompa A, Major J, Jakab M (1999) Is breast cancer cluster influenced by environmental and occupational factors among hospital nurses in Hungary? Pathol Oncol Res 2: 117-121.
Hagmar L, Welinder H, Linden K, et al. (1991) An epidemiological study of cancer risk among workers exposed to ETO using hemoglobin adducts to validate environmental exposure assessments. Occ Environ Health 63: 271-277.
Hogstedt C, Aringer L, Gustavsson A (1986) Epidemiologic support for ETO as a cancer-causing agent. JAMA 255: 1575-1578.
Gardner M, Coggon D, Pannett B, et al. (1989) Workers exposed to ETO: a follow-up study. Brit J Ind Med 46: 860-865.
Steenland K, Stayner L, Griefe A, et al. (1991) A cohort mortality study of workers exposed to ethylene oxide. New Engl J Med 324(20): 1402-1407.
Hornung R, Greife A, Stayner L, et al. (1994) Statistical model for prediction of retrospective exposure to ethylene oxide in an occupational mortality study. Am J Ind Med 25: 825-836.
Steenland K, Spaeth S, Cassinelli R, Laber P, Chang L, Koch K (1998) NIOSH Life Table Program for Personal Computers. Am J Ind Med 34: 517-518.
SAS (1991) SAS User's Guide: Statistics (Version 6.07). NC: SAS Institute Cary.
Steenland K, Deddens J (1997) Increased precision using countermatching in nested case-control studies. Epidemiology 8: 238-242.
Harrell F, Lee K, Pollock B (1988) Regression models in clinical studies: determining relationships between predictors and response. JNCI 80: 1198-1202.
Steenland K, Deddens J, Piacitelli L (2001) Risk assessment for 2,3,7,8-p-dioxin (TCDD) based on an epidemiologic study. Am J Epidemiol 154: 451-458.
Steenland K, Mannetje A, Boffetta P, et al. (2001) Pooled exposure-response and risk assessment for lung cancer in 10 cohorts of silica-exposed workers: an IARC multi-centric study. Cancer Causes Control 12: 773-784.
Steenland K, Deddens J, Stayner L (1998) Diesel exhaust and lung cancer in trucking industry: exposure-response analyses and risk assessment. Am J Ind Med 34: 220-228.
Hertz-Piccioto I, Smith A (1993) Observations on the dose-response curve for arsenic exposure and lung cancer. Scand JWork Environ Health 19: 217-226.
Steenland K, Stayner L, Deddens J (2003) Mortality analyses in a cohort of 18,235 ethylene oxide-exposed workers: follow-up extended from 1987 to 1998. Occup Env Med, in press.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Steenland, K., Whelan, E., Deddens, J. et al. Ethylene oxide and breast cancer incidence in a cohort study of 7576 women (United States). Cancer Causes Control 14, 531–539 (2003). https://doi.org/10.1023/A:1024891529592
Issue Date:
DOI: https://doi.org/10.1023/A:1024891529592