Relationship between established breast cancer risk factors and risk of seven different histologic types of invasive breast cancer.
BACKGROUND
Important differences in the contributions of certain exposures to the risks of ductal versus lobular breast carcinomas have been observed, but few studies have evaluated the relationships between established breast cancer risk factors and other histologic types.


METHODS
Information on family history of cancer and reproductive, hormonal, anthropometric, and lifestyle characteristics were collected in a multicenter population-based case-control study consisting of 3,463 ductal, 274 lobular, 261 ductal-lobular, 91 medullary, 77 tubular, 70 comedo, and 61 mucinous invasive breast carcinoma cases (ages 35-64 years, newly diagnosed 1994-1998) and 4,682 controls. Associations between each of these histologic types and various exposures were evaluated using polytomous regression.


RESULTS
Heterogeneity in the risks of different histologic types of breast cancer was observed for three exposures: menopausal hormone use, body mass index (BMI), and alcohol consumption. Specifically, current use of unopposed estrogen was associated with a reduced risk of ductal carcinoma and increased risk of comedocarcinoma, and current use of estrogen and progestin was associated with elevated risks of ductal-lobular and tubular carcinomas. Among postmenopausal women, BMI was only inversely related to risk of ductal-lobular carcinoma, and alcohol use was only positively related to risk of lobular carcinoma.


CONCLUSIONS
Variations in the associations between known breast cancer risk factors and risk of different breast cancer histologies were observed. Although these findings require confirmation, and the analyses of some histologic groups were limited by small sample sizes, they provide some insight into the different etiologies of various histologic subtypes of breast cancer.
Li
Christopher I
CI
Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, M4-C308, P.O. Box 19024, Seattle, WA 98109-1024, USA. cili@fhcrc.org
Daling
Janet R
JR
Malone
Kathleen E
KE
Bernstein
Leslie
L
Marchbanks
Polly A
PA
Liff
Jonathan M
JM
Strom
Brian L
BL
Simon
Michael S
MS
Press
Michael F
MF
McDonald
Jill A
JA
Ursin
Giske
G
Burkman
Ronald T
RT
Deapen
Dennis
D
Spirtas
Robert
R
D002288:Adenocarcinoma, Mucinous / Q000453:epidemiology / Q000473:pathology; D000328:Adult; D000428:Alcohol Drinking / Q000453:epidemiology; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology / Q000473:pathology; D018275:Carcinoma, Lobular / Q000453:epidemiology / Q000473:pathology; D016022:Case-Control Studies; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D012044:Regression Analysis; D012307:Risk Factors; D014481:United States / Q000453:epidemiology