Risk factors for estrogen receptor-positive breast cancer.
OBJECTIVE
Some risk factors associated with breast cancer may be more predictive of estrogen receptor (ER)- positive than ER-negative tumors.


METHODS
Survey of patients enrolled in a study of breast cancer risk factors.


METHODS
Community population in a northern California county.


METHODS
A total of 234 individuals diagnosed as having breast cancer between July 1, 1997, and June 30, 1999, reporting Marin County, California, residence and participating in a questionnaire regarding exposure to breast cancer risk factors.


METHODS
Diagnosis of ER-positive vs ER-negative breast cancer.


RESULTS
Comparison between ER-positive and ER-negative cases showed several factors predictive of ER-positive tumors. In a multivariate model, years of hormone therapy use remained the most significant predictor of ER-positive disease.


CONCLUSIONS
Patients diagnosed as having ER-positive breast cancer were more likely to have undergone hormone therapy. The excess of ER-positive breast cancers reported in Marin County could, therefore, in part, be related to hormone therapy.
Hwang
E Shelley
ES
Department of Surgery, University of California, San Francisco, Cancer Center, 94115, USA. shelley.hwang@ucsfmedctr.org
Chew
Terri
T
Shiboski
Stephen
S
Farren
Georgianna
G
Benz
Christopher C
CC
Wrensch
Margaret
M
D001943:Breast Neoplasms / Q000737:chemistry* / Q000453:epidemiology / Q000209:etiology; D002140:California / Q000453:epidemiology; D004812:Epidemiologic Methods; D005260:Female; D020249:Hormone Replacement Therapy / Q000009:adverse effects*; D006801:Humans; D008327:Mammography / Q000009:adverse effects; D008875:Middle Aged; D011960:Receptors, Estrogen; D011795:Surveys and Questionnaires; D013997:Time Factors
D011960:Receptors, Estrogen