An investigation of the apparent breast cancer epidemic in France: screening and incidence trends in birth cohorts.

Authors:
Bernard Junod
Bernard Junod
National Institute of Health and Medical Research
France
Per-Henrik Zahl
Per-Henrik Zahl
Norwegian Institute of Public Health
Norway
Robert M Kaplan
Robert M Kaplan
Graduate School of Medicine
Knoxville | United States
Sander Greenland
Sander Greenland
University of California
United States

BMC Cancer 2011 Sep 21;11:401. Epub 2011 Sep 21.

FORMINDEP, Roubaix, France.

Background: Official descriptive data from France showed a strong increase in breast-cancer incidence between 1980 to 2005 without a corresponding change in breast-cancer mortality. This study quantifies the part of incidence increase due to secular changes in risk factor exposure and in overdiagnosis due to organised or opportunistic screening. Overdiagnosis was defined as non progressive tumours diagnosed as cancer at histology or progressive cancer that would remain asymptomatic until time of death for another cause.

Methods: Comparison between age-matched cohorts from 1980 to 2005. All women residing in France and born 1911-1915, 1926-1930 and 1941-1945 are included. Sources are official data sets and published French reports on screening by mammography, age and time specific breast-cancer incidence and mortality, hormone replacement therapy, alcohol and obesity. Outcome measures include breast-cancer incidence differences adjusted for changes in risk factor distributions between pairs of age-matched cohorts who had experienced different levels of screening intensity.

Results: There was an 8-fold increase in the number of mammography machines operating in France between 1980 and 2000. Opportunistic and organised screening increased over time. In comparison to age-matched cohorts born 15 years earlier, recent cohorts had adjusted incidence proportion over 11 years that were 76% higher [95% confidence limits (CL) 67%, 85%] for women aged 50 to 64 years and 23% higher [95% CL 15%, 31%] for women aged 65 to 79 years. Given that mortality did not change correspondingly, this increase in adjusted 11 year incidence proportion was considered as an estimate of overdiagnosis.

Conclusions: Breast cancer may be overdiagnosed because screening increases diagnosis of slowly progressing non-life threatening cancer and increases misdiagnosis among women without progressive cancer. We suggest that these effects could largely explain the reported "epidemic" of breast cancer in France. Better predictive classification of tumours is needed in order to avoid unnecessary cancer diagnoses and subsequent procedures.

Download full-text PDF

Source
http://bmccancer.biomedcentral.com/articles/10.1186/1471-240
Publisher Site
http://dx.doi.org/10.1186/1471-2407-11-401DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3188513PMC

Still can't find the full text of the article?

We can help you send a request to the authors directly.
September 2011
21 Reads

Publication Analysis

Top Keywords

breast-cancer incidence
12
breast cancer
12
age-matched cohorts
12
women aged
8
aged years
8
1980 2005
8
changes risk
8
higher [95%
8
progressive cancer
8
incidence proportion
8
comparison age-matched
8
risk factor
8
cancer
8
incidence
7
screening
6
france
5
cohorts
5
machines operating
4
operating france
4
mammography machines
4

References

(Supplied by CrossRef)
Article in Bull Cancer
S Guerin et al.
Bull Cancer 2009

World Health Oganization et al.
2007
Article in BMJ
S Zackrisson et al.
BMJ 2006
Article in BMJ
KJ Jørgensen et al.
BMJ 2009
Article in JNCI
R Etzioni et al.
JNCI 2002
Article in Breast Cancer Res
M Martinez-Alonzo et al.
Breast Cancer Res 2010
Article in Arch Intern Med
PH Zahl et al.
Arch Intern Med 2008
Article in Int J Epidemiol
DA Freedman et al.
Int J Epidemiol 2004
Article in Int J Epidemiol
PC Gøtzsche et al.
Int J Epidemiol 2004
Article in Int J Epidemiol
DA Freedman et al.
Int J Epidemiol 2004

Similar Publications