Risk Factors

Research has found several risk factors that may increase your chances of getting breast cancer.

Risk factors that increase risk of breast cancer include—

• Getting older.^{1 5 6 7}
• Being younger when you first had your menstrual period.^{1 2 5 6 7}
• Starting menopause at a later age.^{1 2 4}
• Being older at the birth of your first child.^{1 2 6 7}
• Never giving birth.^{1 2 5 6 7}
• Not breastfeeding.⁴
• Personal history of breast cancer or some non-cancerous breast diseases.^{1 2 5 6 7}
• Family history of breast cancer (mother, sister, daughter).^{1 2 5 6 7}
• Treatment with radiation therapy to the breast/chest.^{1 3 4 6}
• Being overweight (increases risk for breast cancer after menopause).^{1 2 3}
• Long-term use of hormone replacement therapy (estrogen and progesterone combined).^{1 2 3 4 6}
• Having changes in the breast cancer-related genes BRCA1 or BRCA2.^{1 2 4}
• Using birth control pills, also called oral contraceptives.^{1 2 4}
• Drinking alcohol (more than one drink a day).^{2 3 4 6}
• Not getting regular exercise.^{1 2 3 4 8}

Having a risk factor does not mean you will get the disease. Most women have some risk factors and most women do not get breast cancer. If you have breast cancer risk factors, talk with your doctor about ways you can lower your risk and about screening for breast cancer.

References

¹Stewart BW & Kleihues P, editors. World Cancer Report. France: IARC Press: 2003.

²Institute of Medicine. National Research Council. Lifestyle Behaviors Contributing to the Burden of Cancer. In: Curry S, Byers T, & Hewitt M, editors. Fulfilling the Potential of Cancer Prevention and Early Detection. Washington, DC: The National Academies Press: 2003. p. 41–86.

³National Cancer Institute. Breast Cancer PDQ: Prevention — Health Professional.

⁴National Cancer Institute. Breast Cancer PDQ: Prevention — Patient.

⁵National Cancer Institute. Breast Cancer PDQ: Treatment — Health Professional.

⁶National Cancer Institute. Breast Cancer PDQ: Treatment — Patient.

⁷U.S. Preventive Services Task Force. Chemoprevention of Breast Cancer: Recommendations and Rationale. July 2002. Agency for Healthcare Research and Quality, Rockville, MD.

⁸International Agency for Research on Cancer. Evaluation. In: Vainio H & Bianchini F, editors. IARC Handbooks of Cancer Prevention: Weight Control & Physical Activity. France: IARC Press: 2002. p. 249–250.