Breast Cancer Research and Treatment

, Volume 100, Issue 2, pp 201–212

Infertility, Ovulation Induction Treatments and the Incidence of Breast Cancer—a Historical Prospective Cohort of Israeli Women

  • L. Lerner-Geva
  • L. Keinan-Boker
  • T. Blumstein
  • V. Boyko
  • L. Olmar
  • S. Mashiach
  • J. Rabinovici
  • G. Potashnik
  • E. Lunenfeld
  • J. G. Schenker
  • A. Shushan
  • A. Fishman
  • I. Cohen
  • I. Vagman
  • B. Lunenfeld
Epidemiology

DOI: 10.1007/s10549-006-9238-4

Cite this article as:
Lerner-Geva, L., Keinan-Boker, L., Blumstein, T. et al. Breast Cancer Res Treat (2006) 100: 201. doi:10.1007/s10549-006-9238-4

Abstract

Context

Ovulation induction drugs may be associated with increased breast cancer risk. Results so far have been inconclusive.

Objective

To evaluate the association between infertility, exposure to ovulation induction drugs and the incidence of breast cancer.

Design

Historical prospective cohort and nested case–control study.

Setting

Institutional practice

Patients

About 5,788 women attending five infertility centers in Israel between 1964 and 1984.

Intention

Abstracting of medical records and telephone interviews.

Main outcome measure

Breast cancer incidence was determined through linkage with the National Cancer Registry database. Standardized incidence ratios (SIRs) and 95% confidence intervals were computed by comparing the observed to the expected cancer rates in the general population. In addition, a nested case–control study within the cohort was performed with interviews of breast cancer cases and two matched controls.

Results

The study cohort included 120,895 women years of follow-up. Compared to 115.2 expected breast cancer cases, 131 cases were observed (SIR = 1.1; 95% CI 0.9–1.4). Risk for breast cancer was significantly higher for women treated with clomiphene citrate (SIR = 1.4; 95% CI 1.0–1.8). Similar results were noted when comparisons were carried out between treated and untreated women, and when multivariate models were applied.

In the nested case–control study, higher cycle index (OR = 2.2; 95% CI 1.0–4.8) and treatment with clomiphene citrate (OR=2.7; 95% CI 1.3–5.7) were associated with higher risk for breast cancer.

Conclusion

Infertility and usage of infertility drugs in general are not associated with increased risk for breast cancer. However, for infertile women treated with clomiphene citrate, breast cancer risk is elevated.

Key words

Breast cancer Clomiphene citrate Infertility Ovulation induction Prospective 

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • L. Lerner-Geva
    • 1
    • 9
  • L. Keinan-Boker
    • 2
    • 9
  • T. Blumstein
    • 1
  • V. Boyko
    • 1
  • L. Olmar
    • 1
  • S. Mashiach
    • 3
    • 9
  • J. Rabinovici
    • 3
    • 9
  • G. Potashnik
    • 4
  • E. Lunenfeld
    • 4
  • J. G. Schenker
    • 5
  • A. Shushan
    • 5
  • A. Fishman
    • 6
    • 9
  • I. Cohen
    • 6
    • 9
  • I. Vagman
    • 7
  • B. Lunenfeld
    • 8
  1. 1.Women and Children’s Health Research Unit, Sheba Medical CenterGertner Institute for Epidemiology and Health Policy ResearchRamat GanIsrael
  2. 2.Haifa UniversitySchool of Public HealthHaifaIsrael
  3. 3.Obstetrics and GynecologyChaim Sheba Medical CenterRamat GanIsrael
  4. 4.Obstetrics and GynecologySoroka Medical CenterBeer ShevaIsrael
  5. 5.Obstetrics and GynecologyHadassah Ein Karem Medical CenterJerusalemIsrael
  6. 6.Obstetrics and GynecologySapir Medical CenterKfar SabaIsrael
  7. 7.Obstetrics and GynecologyTel Aviv Medical CenterTel AvivIsrael
  8. 8.Bar Ilan UniversityRamat GanIsrael
  9. 9.Sackler School of MedicineTel Aviv UniversityTel AvivIsrael