gms | German Medical Science

Kongress Medizin und Gesellschaft 2007

17. bis 21.09.2007, Augsburg

Aspirin use and breast cancer risk – a meta analysis and meta regression of epidemiological studies from 2001 to 2005

Meeting Abstract

  • Sandra Mangiapane - Technische Universität Berlin, Berlin
  • Maria Blettner - Johannes Gutenberg Universität Mainz, Mainz
  • Peter Schlattmann - Charite Berlin, Berlin

Kongress Medizin und Gesellschaft 2007. Augsburg, 17.-21.09.2007. Düsseldorf: German Medical Science GMS Publishing House; 2007. Doc07gmds256

The electronic version of this article is the complete one and can be found online at:

Published: September 6, 2007

© 2007 Mangiapane et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Background: Recent meta-analysis suggest that aspirin may reduce breast cancer risk, but failed to examine reasons for heterogeneity and to investigate a dose response relationship. Referring to this, our meta-analysis aimed to complete the current research.

Methods: We systematically searched for cohort studies and case-control studies in Medline, Cancerlit and Embase from 2001 to 2004, which evaluated the association between aspirin and breast cancer risk and reported a relative risk or odds ratio including confidence intervals or information to permit their calculation. We calculated a pooled estimate for the RR and investigated reasons for heterogeneity between the individual studies and analysed a dose response relationship considering frequency and duration of use using random effect models.

Results: We identified 10 studies (4 cohort studies and 6 case-control-studies) which met the inclusion criteria. The combined estimate of the RR was 0.75 (95 % CI=0.65-0.87) using the random effects model. Heterogeneity between the studies could not be explained by the covariates study type and study population. The combination of frequency and duration of aspirin use resulted in a significant dose-response-relationship between aspirin use and breast cancer risk. Each additional pillyear reduced the breast cancer risk about 7 %.

Conclusion: Our meta-analysis supports the current evidence, that aspirin may reduce breast cancer risk. Results dos not vary among different study types. Moreover, a dose-response-relationship seems to exist. However, results have to be interpreted carefully, as exposure categories were defined very heterogeneously among the studies which weakens the validity of the pooled estimates.