Trends in hormone therapy and breast cancer incidence - results from the German Network of Cancer Registries.
OBJECTIVE
Menopausal hormone therapy (HT) is a proven risk factor for breast cancer. Recent reports presented declining trends in breast cancer incidence, which were attributed to parallel declining trends in HT. Therefore, we analyzed recent data on hormone therapy and breast cancer incidence in Germany.


METHODS
We performed a population-based survey using breast cancer incidence (from cancer registries) and hormone prescription data (from health insurances) for the time period from 1997 to 2006. Age-standardized rates were calculated and joinpoint regression analyses for trends were performed.


RESULTS
Prescription of HT started to decline in 1999; about 2 years later, a parallel decline in breast cancer incidence was observed. HT prescription decreased by 69% up to 2006, and breast cancer incidence by 6.8% for all age groups (2002-2005) and 12.8% in the age group from 50 to 69 years. The reductions in HT prescription and breast cancer incidence were markedly correlated across the federal states in Germany.


CONCLUSIONS
The recent decline in breast cancer incidence following decreasing HT prescription suggests a causal relationship between the risk of breast cancer and HT in Germany. Even after the 'big HT drop' in Germany, significant differences in HT prescription as well as breast cancer incidence persist at the federal state level. These results should be discussed in a public health context.
Katalinic
Alexander
A
Institute for Cancer Epidemiology, University of Lübeck, Lübeck, Germany. alexander.katalinic@krebsregister-sh.de
Lemmer
Anna
A
Zawinell
Anette
A
Rawal
Rajesh
R
Waldmann
Annika
A
D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology*; D004967:Estrogens / Q000627:therapeutic use*; D005260:Female; D005858:Germany / Q000453:epidemiology; D020249:Hormone Replacement Therapy / Q000639:trends*; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D055656:Prescriptions; D012042:Registries; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D044465:White People
D004967:Estrogens