Urban-rural differences in breast cancer incidence by hormone receptor status across 6 years in Egypt.
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.
Dey
Subhojit
S
Department of Epidemiology, School of Public Health, University of Michigan, 109 Observatory Street, Ann Arbor, MI, 48109, USA.
Soliman
Amr S
AS
Hablas
Ahmad
A
Seifeldin
Ibrahim A
IA
Ismail
Kadry
K
Ramadan
Mohamed
M
El-Hamzawy
Hesham
H
Wilson
Mark L
ML
Banerjee
Mousumi
M
Boffetta
Paolo
P
Harford
Joe
J
Merajver
Sofia D
SD
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D004534:Egypt / Q000453:epidemiology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D009367:Neoplasm Staging; D009376:Neoplasms, Hormone-Dependent / Q000453:epidemiology* / Q000473:pathology; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism; D012042:Registries; D012424:Rural Population / Q000706:statistics & numerical data*; D014505:Urban Population / Q000706:statistics & numerical data*; D055815:Young Adult
D011960:Receptors, Estrogen; D011980:Receptors, Progesterone