Hormone replacement therapy, mammography screening and changing age-specific incidence rates of breast cancer: an ecological study comparing two European populations
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In 2003, for the first time, US breast cancer incidence rates have fallen. Experts argue whether this is due to the reduced uptake of screening mammography or to lower use of Hormone Replacement Therapy (HRT). This study aims to disentangle the respective impact of screening and HRT on age-incidence rates and histology of breast cancer, by comparing two populations with comparably high levels of screening mammography, but with different prevalence of HRT.
We included all invasive breast cancers recorded at the Geneva cancer registry (n = 4,909) and the Netherlands Cancer Registry (n = 152,428) between 1989–2003. We compared age-specific incidence rates and trends in histological subtyping between the two populations.
Between 1989–1991, incidence rates increased with age in both populations. In 2001–2003, women aged 60–64 years showed highest incidence rates in Geneva, while in the Netherlands incidence rates continued to increase with age. The annual increase in ductal cancer incidence was similar in the Netherlands (2.3%) and Geneva (2.5%), but the annual increase in lobular cancer was sharper in Geneva (10%) than in the Netherlands (5%).
The sharp differences in age distribution and histological subtyping of breast cancer between two European populations are not attributable to screening, since both populations have a high uptake of mammography screening. Since the prevalence of HRT use is very high in Geneva and rather low in the Netherlands, HRT may explain these discrepancies. However, other etiological factors and differences in histological assessment may also have played a role.
KeywordsBreast cancer Hormone replacement therapy Incidence Population-based Screening
Dr. H. M. Verkooijen was financially supported by a PROSPER Grant (3233-069350) from the Swiss National Science Foundation.
- 1.Ravdin PA, Cronin KA, Howlander N et al (2006) A sharp decrease in breast cancer incidence in the United States in 2003. Breast Cancer Res Treatm 100:S6–S7Google Scholar
- 3.Olsen O, Gøtzsche PC (2001) Systematic review of screening for breast cancer with mammography. The Lancet Publishing Group, London, UKGoogle Scholar
- 21.Bouchardy C (1997) Switzerland, Geneva. In: Parkin DM, Whelan SL, Ferlay J, Raymond L, Young J (eds) Cancer incidence in five continents. Vol. VII. International Agency for Research on Cancer, LyonGoogle Scholar
- 26.World Health Organization (1976) ICD-O International classification of diseases for oncology. GenevaGoogle Scholar
- 27.GLIM 4 the statistical system for generalized linear interactive modelling [computer program]. (1993) Oxford University Press, OxfordGoogle Scholar