Abstract
Breast cancer incidence is higher in developed countries with higher rates of estrogen receptor positive (ER+) tumors. ER+ tumors are caused by estrogenic exposures although known exposures explain approximately 50% of breast cancer risk. Unknown risk factors causing high breast cancer incidence exist that are estrogenic and development-related. Xenoestrogens are such risk factors but are difficult to study since developed countries lack unexposed populations. Developing countries have urban-rural populations with differential exposure to xenoestrogens. This study assessed urban-rural breast cancer incidence classified by hormone receptor status using data from Gharbiah population-based cancer registry in Egypt from 2001 to 2006. Urban ER+ incidence rate (per 100,000 women) was 2-4 times (IRR = 3.36, 95% CI = 4.84, 2.34) higher than rural incidence rate. ER-incidence rate was 2-3 times (IRR = 1.86, 95% CI = 2.38, 1.45) higher in urban areas than in rural areas. Our findings indicate that urban women may probably have a higher exposure to xenoestrogens.
Original language | English (US) |
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Pages (from-to) | 149-160 |
Number of pages | 12 |
Journal | Breast Cancer Research and Treatment |
Volume | 120 |
Issue number | 1 |
DOIs | |
State | Published - Feb 2010 |
Keywords
- Breast cancer incidence
- Egypt
- Hormone receptor status
- Mammary stem cells
- Xenoestrogens
ASJC Scopus subject areas
- Oncology
- Cancer Research