Prognostic characteristics of breast cancer among postmenopausal hormone users in a screened population.
OBJECTIVE
We determined the risk of breast cancer and tumor characteristics among current postmenopausal hormone therapy users compared with nonusers, by duration of use.


METHODS
From January 1996 to December 2000, data were collected prospectively on 374,465 postmenopausal women aged 50 to 79 years who underwent screening mammography. We calculated the relative risk (RR) of breast cancer (invasive or ductal carcinoma-in-situ) and type of breast cancer within 12 months of postmenopausal therapy use among current hormone users with a uterus (proxy for estrogen and progestin use) and without a uterus (proxy for estrogen use), compared with nonusers.


RESULTS
Compared with nonusers, women using estrogen and progestin for >/= 5 years were at increased risk of breast tumors of stage 0 or I (RR, 1.51; 95% CI, 1.37 to 1.66), stage II or higher (RR, 1.46; 95% CI, 1.30 to 1.63), size </= 20 mm (RR, 1.59; 95% CI, 1.43 to 1.76), size greater than 20 mm (RR, 1.24; 95% CI, 1.09 to 1.42), grade 1 or 2 (RR, 1.60; 95% CI, 1.44 to 1.77), grade 3 or 4 (RR, 1.54; 95% CI, 1.37 to 1.73), and estrogen receptor-positive (RR, 1.72; 95% CI, 1.55 to 1.90). Estrogen-only users were slightly more likely to have estrogen receptor-positive breast cancer compared with nonusers (RR, 1.14; 95% CI, 1.06 to 1.23).


CONCLUSIONS
Use of estrogen and progestin postmenopausal hormone therapy for five years or more increased the likelihood of developing breast cancer, including both tumors with favorable prognostic features and tumors with unfavorable prognostic features.
Kerlikowske
Karla
K
San Francisco Veterans Affairs Medical Center, General Internal Medicine Section, 111A1, 4150 Clement St, San Francisco, CA 94121, USA. kerliko@itsa.ucsf.edu
Miglioretti
Diana L
DL
Ballard-Barbash
Rachel
R
Weaver
Donald L
DL
Buist
Diana S M
DS
Barlow
William E
WE
Cutter
Gary
G
Geller
Berta M
BM
Yankaskas
Bonnie
B
Taplin
Stephen H
SH
Carney
Patricia A
PA
D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D002278:Carcinoma in Situ / Q000175:diagnosis / Q000453:epidemiology; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis / Q000453:epidemiology; D004338:Drug Combinations; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D004967:Estrogens / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008403:Mass Screening; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D017698:Postmenopause / Q000187:drug effects*; D011372:Progestins / Q000009:adverse effects*; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors
D004338:Drug Combinations; D004967:Estrogens; D011372:Progestins