In general, what factors increase or decrease the chance of developing breast cancer and/or ovarian cancer?
The following factors have been associated with increased or decreased risk of developing breast and/or ovarian cancer in the general population. It is not yet known exactly how these factors influence risk in people with BRCA1 or BRCA2 mutations. In addition, a significant portion of hereditary breast cancers are not associated with BRCA1 or BRCA2 mutations (8).
No data have been reported to date regarding the effects of HRT on breast cancer risk among women carrying harmful BRCA1 or BRCA2 mutations, and only limited data are available regarding HRT use and ovarian cancer risk among such women. In one study, HRT use did not appear to affect ovarian cancer risk among women with BRCA1 or BRCA2 mutations (29).
When considering HRT use, both the potential harms and benefits of this type of treatment should be discussed carefully by a woman and her health care provider.
7. Obesity—Substantial evidence indicates that obesity is associated with an increased risk of breast cancer, especially among postmenopausal women who have not used HRT (24). Evidence also suggests that obesity is associated with increased mortality (death) from ovarian cancer (30).
8. Lynch HT, Silva E, Snyder C, Lynch JF. Hereditary breast cancer: Part I. Diagnosing hereditary breast cancer syndromes. The Breast Journal 2008; 14(1):3–13.
24. PDQ® Cancer Information Summary. National Cancer Institute; Bethesda, MD. Breast Cancer Prevention (PDQ®) – Health Professional. Date last modified 04/30/2009. Available at: http://www.cancer.gov/cancertopics/pdq/prevention/breast/healthprofessional.
25. PDQ® Cancer Information Summary. National Cancer Institute; Bethesda, MD. Ovarian Cancer Prevention (PDQ®) – Health Professional. Date last modified 04/03/2008. Available at: http://www.cancer.gov/cancertopics/pdq/prevention/ovarian/healthprofessional.
26. Whittemore AS, Balise RR, Pharoah PDP, et al. Oral contraceptive use and ovarian cancer risk among carriers of BRCA1 or BRCA2 mutations. British Journal of Cancer 2004; 91(11):1911–1915.
27. National Heart, Lung, and Blood Institute. Women’s Health Initiative. Retrieved April 20, 2009, from: http://www.nhlbi.nih.gov/whi.
28. Anderson GL, Judd HL, Kaunitz AM, et al. Effects of estrogen plus progestin on gynecologic cancers and associated diagnostic procedures: The Women’s Health Initiative randomized trial. Journal of the American Medical Association 2003; 290(13):1739–1748.
29. Kotsopoulos J, Lubinski J, Neuhausen SL, et al. Hormone replacement therapy and the risk of ovarian cancer in BRCA1 and BRCA2 mutation carriers. Gynecologic Oncology 2006; 100(1):83–88.
30. Calle EE, Rodriguez C, Walker-Thurmond K, Thun MJ. Overweight, obesity, and mortality from cancer in a prospectively studied cohort of U.S. adults. New England Journal of Medicine 2003; 348(17):1625–1638.
31. Prentice RL, Caan B, Chlebowski RT, et al. Low-fat dietary pattern and risk of invasive breast cancer: The Women’s Health Initiative Randomized Controlled Dietary Modification Trial. Journal of the American Medical Association 2006; 295(6):629–642.
Source: National Cancer Institute