BMC Cancer (2001) 1:8 BRMesCeaCrcahncaerrti(c2le001) 1:8 http://www.biomedcentral.com/1471-2407/1/8 Organochlorine exposures influence on breast cancer risk and survival according to estrogen receptor status: a Danish cohort- nested case-control study Annette P Høyer*1, Torben Jørgensen2, Fritz Rank3 and Philippe Grandjean4,5 Address: 1The Copenhagen Center for Prospective Population Studies (affiliation) Harsdorffsvej 1B, 2tv, DK-1874 Frederiksberg C, Denmark, 2Centre for Preventive Medicine, KAS Glostrup, Medical Dept. C/F, Entrance 8, 7th floor, Ndr. Ringvej, DK-2600 Glostrup, Denmark, 3Dept. of Pathology, Rigshopitalet, the National University Hospital, Blegdamsvej 9, DK-2100 Copenhagen Ø, Denmark, 4Institute of Community Health, Odense University, Winsløwparken 17, DK-5000, Denmark and 5Department of Environmental Health and Neurology, Boston School of Medicinal and Public Health, MA, USA E-mail: Annette P Høyer* - aph@post8.tele.dk; Torben Jørgensen - tojo@glostruphosp.kbhamt.dk; Fritz Rank - rh02869@rh.dk; Philippe Grandjean - pgrand@health.sdu.dk *Corresponding author Published: 30 July 2001 BMC Cancer 2001, 1:8 Received: 11 May 2001 Accepted: 30 July 2001 This article is available from: http://www.biomedcentral.com/1471-2407/1/8 © 2001 Høyer et al; licensee BioMed Central Ltd. Verbatim copying and redistribution of this article are permitted in any medium for any non-com- mercial purpose, provided this notice is preserved along with the article's original URL. For commercial use, contact info@biomedcentral.com Abstract Background: The relationship between breast cancer and organochlorine exposure is controversial and complex. As estrogen receptor positive and negative breast cancer may represent different entities of the disease, this study was undertaken to evaluate organochlorines influence on breast cancer risk and survival according to receptor status. Methods: The background material stems from the Copenhagen City Heart Study (Denmark 1976-78). The breast cancer risk was investigated in a cohort nested case-control design including 161 cases and twice as many breast cancer free controls. The cases served as a cohort in the survival analysis. Serum organochlorine concentrations were determined by gaschromotography. Results: The observed increased breast cancer risk associated with exposure to dieldrin derived from women who developed an estrogen receptor negative (ERN) tumor (Odds ratio [OR] I vs. IV quartile, 7.6, 95% confidence interval [95% CI] 1.4-46.1, p-value for linear trend 0.01). Tumors in women with the highest dieldrin serum level were larger and more often spread at the time of diagnosis than ERP tumors. The risk of dying was for the remaining evaluated compounds higher among patients with ERP breast cancer when compared to those with ERN. In the highest quartile of polychlorinated biphenyls (ΣPCB) it was more than 2-fold increased (Relative risk [RR] I vs. IV quartile, 2.5, 95% CI 1.1-5.7), but no dose-response relation was apparent. Conclusion: The results do not suggest that exposure to potential estrogenic organochlorines leads to development of an ERP breast cancer. A possible adverse effect on prognosis of hormone- responsive breast cancers needs to be clarified.