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Kongress Medizin und Gesellschaft 2007

17. bis 21.09.2007, Augsburg

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Physical activity and postmenopausal breast cancer: effect modification by breast cancer subtypes

Meeting Abstract

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  • Martina Schmidt - Unit of Environmental Epidemiology, German Cancer Research Center, Heidelberg
  • Karen Steindorf - Unit of Environmental Epidemiology, German Cancer Research Center, Heidelberg
  • Elke Mutschelknauss - Institute for Medical Biometrics and Epidemiology, University Clinic Hamburg-Eppendorf, Hamburg
  • Tracy Slanger - Division of Cancer Epidemiology, German Cancer Research Center, Heidelberg
  • Nadia Obi - Institute for Medical Biometrics and Epidemiology, University Clinic Hamburg-Eppendorf, Hamburg
  • Silke Kropp - Division of Cancer Epidemiology, German Cancer Research Center, Heidelberg
  • Jürgen Berger - Institute for Medical Biometrics and Epidemiology, University Clinic Hamburg-Eppendorf, Hamburg
  • Wilhelm Braendle - Clinic for Gynecology, University Clinic Hamburg-Eppendorf, Hamburg
  • Dieter Flesch-Janys - Institute for Medical Biometrics and Epidemiology, University Clinic Hamburg-Eppendorf, Hamburg
  • Jenny Chang-Claude - Division of Cancer Epidemiology, German Cancer Research Center, Heidelberg

Kongress Medizin und Gesellschaft 2007. Augsburg, 17.-21.09.2007. Düsseldorf: German Medical Science GMS Publishing House; 2007. Doc07gmds361

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/gmds2007/07gmds361.shtml

Published: September 6, 2007

© 2007 Schmidt et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

Text

Introduction: Evidence exists for an inverse association between physical activity (PA) and breast cancer risk [1]. Proposed biological mechanisms range from hormone modulation to up-regulated immune functioning [2] but are still unclear. Information on the association of PA with breast cancer according to histology and hormone-receptor status is scarce, yet may provide insight into mechanisms of action. Therefore, we analyzed the association of PA with breast cancer subtypes in 3414 postmenopausal cases and 6570 controls.

Material and Methods: In a large case-control study of postmenopausal breast cancer including women of age 50 to 74 years from two regions in Germany (MARIE study), comprehensive data on risk factors were collected. Physical activity in the age periods 30-49 and 50+ years was assessed including occupational activities, household activities, walking, cycling, and sports. Polytomous logistic regression was used to model the association between the PA variables and breast cancer according to estrogen- and progesterone- receptor-status (ER/PR) and different histological types.

Results: We found a protective effect of sports and cycling in the age period 50+ years (adjusted OR=0.77 (0.67, 0.88), most active vs. inactive), while the effect of sports/cycling in the period 30-49 years was weak. The protective effect was even stronger for ER+/PR+ carcinomas, but there was no effect for ER-/PR- carcinomas. Moreover, the effect was more pronounced for ductal invasive tumors and was strongest when current or recent hormone users were excluded (OR=0.67 (0.50, 0.90), ER+/PR+ ductal). Possibly due to smaller numbers, effects were less consistent for lobular invasive tumors. Overall, effects of sports/cycling were independent from adult weight gain and BMI. Walking, occupational and household activity showed only very weak effects.

Conclusion: Our findings suggest that sports and cycling may reduce postmenopausal breast cancer risk at least in part via a hormonal pathway and not solely by reducing body weight.

Outline

References

1.
Monninkhof EM, Elias SG, Vlems FA, et al. Physical activity and breast cancer, a systematic review of current evidence. Epidemiology. 2007;18:137-57.
2.
Hoffman-Goetz L, Apter D, Demark Wahnefried W, Goran MI, McTiernan A, Reichman ME. Possible mechanisms mediating an association between physical activity and breast cancer. Cancer. 1998;83(3 Suppl):621-628.