Breast Cancer Research and Treatment

, Volume 120, Issue 2, pp 519–523

Changing pattern of age-specific breast cancer incidence in the Swiss canton of Geneva

  • Christine Bouchardy
  • Massimo Usel
  • Helena M. Verkooijen
  • Gérald Fioretta
  • Simone Benhamou
  • Isabelle Neyroud-Caspar
  • Robin Schaffar
  • Georges Vlastos
  • Yves Wespi
  • Peter Schäfer
  • Elisabetta Rapiti
Epidemiology

DOI: 10.1007/s10549-009-0478-y

Cite this article as:
Bouchardy, C., Usel, M., Verkooijen, H.M. et al. Breast Cancer Res Treat (2010) 120: 519. doi:10.1007/s10549-009-0478-y

Abstract

Hormone replacement therapy (HRT) use declined sharply after mid-2002, when the Women’s Health Initiative trial reported an association between breast cancer occurrence and HRT. Hypothesized mechanism behind this association is that HRT promotes growth of pre-existing small tumors, leading to earlier tumor detection. We evaluated the impact of the sudden decline in HRT use on age distribution of breast cancer in Geneva. We included all incident breast cancer cases recorded from 1975 to 2006 at the Geneva cancer registry. We calculated mean annual incidence rates per 100,000 for 2 year periods for three age groups and assessed temporal changes by joinpoint regression. We compared age-specific incidence curves for different periods, reflecting different prevalence rates of HRT use. After increasing constantly between 1986 and 2002 among women aged 50–69 years [annual percent change (APC): +4.4, P < 0.0001], rates declined sharply after 2003 (APC: −6.0; P = 0.0264). Age-specific breast cancer rates changed dramatically with changes in prevalence of HRT use. During low HRT prevalence, breast cancer incidence increased progressively with age, when HRT prevalence was reaching its maximum (1995–2002), higher rates were seen in 60- to 64-year-old women, with a concomitant decrease in risk among elderly. After the sudden decline in HRT use, the incidence peak diminished significantly and incidence increased again with age. Following the abrupt decline in HRT use in Geneva, breast cancer incidence rates among post-menopausal women decreased considerably with striking changes in age-specific incidence rates before, during and after the peak in HRT prevalence.

Keywords

Breast cancer Diagnosis Incidence Hormone replacement therapy 

Copyright information

© Springer Science+Business Media, LLC. 2009

Authors and Affiliations

  • Christine Bouchardy
    • 1
  • Massimo Usel
    • 1
  • Helena M. Verkooijen
    • 1
    • 2
  • Gérald Fioretta
    • 1
  • Simone Benhamou
    • 3
    • 4
  • Isabelle Neyroud-Caspar
    • 1
  • Robin Schaffar
    • 1
  • Georges Vlastos
    • 5
  • Yves Wespi
    • 6
  • Peter Schäfer
    • 5
  • Elisabetta Rapiti
    • 1
  1. 1.Geneva Cancer Registry, Institute for Social and Preventive MedicineGeneva UniversityGenevaSwitzerland
  2. 2.Department of Community, Occupational and Family MedicineNational University of SingaporeKent RidgeSingapore
  3. 3.INSERM, U946, Fondation Jean Dausset, CEPHParisFrance
  4. 4.CNRS FRE2939, Gustave-Roussy InstituteVillejuifFrance
  5. 5.Clinic of Gynecology, Senology, Department of Obstetrics and GynecologyGeneva University HospitalsGenevaSwitzerland
  6. 6.Group of Gynecologists and Obstetricians GenevaAssociation of Physicians of the Canton of GenevaGenevaSwitzerland

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