Breast cancer is a disease of a multifactor origin. Risk factors for breast cancer may be classified into four broad categories: genetic/familial1,2,3, reproductive/hormonal2,4, lifestyle and environmental5,6,7. Established risk factors contributing to its incidence are family history, parity, age at first child birth, age at menarche and genetic factors.
Questions on potential reasons for increasing breast cancer rates in Europe were addressed several times in 2008. E.g. the topic was discussed at the Open Forum of CASCADE (Network of Excellence focused on Human Health and Endocrine Disruption) in Brussels and at a meeting of members of the European Parliament. Not only in Europe, but in many other countries worldwide an increase in female breast cancer rates is reported. A better understanding of the reasons for this increase is of high importance for developing effective public health prevention measures.
Frequently concerns emerge that environmental factors might contribute to the rising incident rates, although the evidence for such associations is limited6,7. E.g. at the CASCADE Open Forum exposure to endocrine disrupting chemicals was discussed as a contributor.
On the other hand, recent publications attribute the rising breast cancer incidence rates to increasing participation in mammography screening programs8,9. It has to be considered that the value of participation in screening programs in early detection and subsequent effective treatment of breast cancer is frequently highlighted in European and U.S. public health programs.
A literature study examining the evidence for associations between the risk factors from the four categories mentioned above and breast cancer may provide valuable input to this discussion. The study might also clarify the extent in which changes in these risk factors may explain the increased incidence of breast cancer.
The objectives of this literature research are to:
”¢ Summarize currently available scientific literature regarding risk factors for breast cancer, including especially the effect of mass screening
”¢ Evaluate the extent in which changes in these risk factors may explain the rise in breast cancer incidence
”¢ Provide recommendations on how potential future research into the association between environmental factors and breast cancer should be conducted.
The literature review should include a description of time trends and age distributions in the incidence and mortality of breast cancer. It should express the observed or postulated associations in a quantitative manner, depicting the current state of the art of knowledge on these risk factors. It should also identify the strengths and weaknesses of the available evidence and should provide a well based direction for future research.
The principal investigator will be required to submit a progress report during halftime of project and a detailed review of the results at the end of the project. It is expected that the results will be published in peer-reviewed journals, and the investigators are encouraged to present their preliminary findings at appropriate scientific meetings.
1Foulkes W and Narod S "Hereditary breast and ovarian cancer; Epidemiology, genetics, screening and predictive testing", Clin. Invest. Med. (1995) 18:473-483.
2Narod S "Hormonal prevention of hereditary breast cancer", Ann. NY Acad. Sci. (2001) 952:36-43.
3de Jong M, Nolte I, te Meerman G, van der Graaf W, Oosterwijk J, Kleibeuker J, Schaapveld M, de Vries E "Genes other than BRCA1 and BRCA2 involved in breast cancer susceptibility", J. Med. Genet (2002) 39:225-242.
4Hunter D, Spiegelman D, Adami H, Van den Brandt P, Folsom A, Goldbohm R, Graham S, Howe G, Kushi L, Marshall J, Miller A, Speizer F, Willet W, Wolk A, Yuan S "Non-dietary factors as risk factors for breast cancer, and as effect modifiers of the association of fat intake and risk of breast cancer", Cancer Causes Control (1997) 8:49-56.
5Standford J, Herrinton S, Schawartz M, Weiss N "Breast cancer incidence in Asian migrants to the United States and their descendants", Epidemiology (1995) 6:181-183.
6Salehi F, Turner MC, Phillips KP, Wigle DT, Krewski D, Aronson KJ "Review of the etiology of breast cancer with special attention to organochlorines as potential endocrine disruptors", J. of Toxicol. Environ. Health (2008) Part B, 11:3,276-300.
7Brody JG, Moysich KB, Humblet O, Attfield KR, Beehler GP, Rudel RA "Environmental pollutants and breast cancer", Cancer Supplement (2007) 109(12): 2667-2711.
8Van Steenbergen LN, Voogd AC, Roukema JA, Louwman WJ, Duijm LE, Coebergh JW, van de Poll-Franse LV "Screening caused by rising incident rates of ductal carcinoma in situ of the breast", Breast Cancer Res Treat. (2009) 115(1):181-3.
9Malmgren JA, Atwood MK, Kaplan HG "Increase in mammography detected breast cancer over time at a community based regional cancer center: a longitudinal cohort study 1990-2005", BMC Cancer (2008) 10; 8:131.