Infertility drugs and the risk of breast cancer: findings from the National Institute of Child Health and Human Development Women's Contraceptive and Reproductive Experiences Study.
OBJECTIVE
To determine the association between infertility drug use and invasive breast cancer in a population-based case-control study.


METHODS
Multicenter case-control study.


METHODS
Women aged 35 to 64 years in metropolitan Atlanta, Detroit, Los Angeles, Philadelphia, and Seattle.


METHODS
The 4,575 case patients had histologically confirmed primary invasive breast cancer. The 4,682 control subjects were women without breast cancer identified in the same geographic locations using randomized-digit dialing.


METHODS
A standardized questionnaire focusing on reproductive health and family history as well as use of oral contraceptives and other hormones and infertility drugs was administered to all subjects. Data on the type of breast cancer were also obtained.


METHODS
Odds ratios examining the association between use of various infertility drugs and invasive breast cancer.


RESULTS
Overall, a history of infertility drug use was not associated with the risk of developing breast cancer. Compared with women who never used any fertility medication, however, women using human menopausal gonadotropin (hMG) for > or = 6 months or for at least six cycles had a relative risk of breast cancer ranging between 2.7 to 3.8.


CONCLUSIONS
Long-term use of certain infertility drugs could adversely affect risk of breast cancer. Additional confirmatory studies are needed.
National Cancer Institute Surveillance, Epidemiology, and End Results Registry, Department of Obstetrics and Gynecology, Henry Ford Health System, Detroit, Michigan, USA. rtb@bhs.org
Ronald T
RT
Burkman
Mei-Tzu C
MT
Tang
Kathleen E
KE
Malone
Polly A
PA
Marchbanks
Jill A
JA
McDonald
Suzanne G
SG
Folger
Sandra A
SA
Norman
Brian L
BL
Strom
Leslie
L
Bernstein
Giske
G
Ursin
Linda K
LK
Weiss
Janet R
JR
Daling
Michael S
MS
Simon
Robert
R
Spirtas
D000328:Adult; D001943:Breast Neoplasms / Q000139:chemically induced*; D016022:Case-Control Studies; D005260:Female; D005300:Fertility Agents, Female / Q000009:adverse effects*; D006801:Humans; D007407:Interviews as Topic; D016015:Logistic Models; D008596:Menotropins / Q000009:adverse effects; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors
D005300:Fertility Agents, Female; D008596:Menotropins