RELATION OF SMOKING TO BREAST-CANCER BY ESTROGEN-RECEPTOR STATUS

It has been suggested that smoking is associated with estrogen-negativ e breast cancer but not with estrogen-positive breast cancer, A popula tion-based case-control study was conducted in Geneva, Switzerland, to determine the relation of passive and active smoking to breast cancer when the referent unexposed category consisted of women unexposed to active and passive smoke. The 242 patients with breast cancer (cases), in whom estrogen receptor (ER) status was determined on biopsy materi al, were compared with 1,059 women free of breast cancer (controls), L ifetime history of active and passive smoking was recorded year by yea r, between age 10 and the date of interview, Prevalence rates of ER+ t umors were 74.7% in pre-menopausal women and 74.2% in post-menopausal women, Post-menopausal active smokers had a lower prevalence of ER+ tu mors (70.0%, p = ns), Among pre-menopausal women, the age-adjusted ORs of breast cancer with having smoked an average of greater than or equ al to 20 cigarettes per day (cpd) during lifetime were 2.7 for ER- tum ors and 2.6 for ER+ tumors. Among post-menopausal women, corresponding ORs were 5.7 for ER- tumors and 2.4 for ER+ tumors. Smoking was relat ed to both ER- and ER+ breast cancer in pre-and post-menopausal women, but the strength of the association appeared to be greater for ER- tu mors among post-menopausal women. (C) 1998 Wiley-Liss, Inc.