What are the risk factors for breast cancer?

From the Guidelines

Breast cancer risk factors include a combination of non-modifiable and modifiable factors, with the most significant non-modifiable risk factors being increasing age, family history of breast cancer, and certain genetic mutations, such as BRCA1 and BRCA2, as identified in the most recent study 1.

Non-Modifiable Risk Factors

• Increasing age, especially over 50
• Family history of breast cancer
• Personal history of breast cancer
• Certain genetic mutations, particularly BRCA1 and BRCA2
• Early menstruation (before age 12)
• Late menopause (after age 55)
• Dense breast tissue
• Previous chest radiation

Modifiable Risk Factors

• Alcohol consumption
• Obesity, particularly after menopause
• Hormone replacement therapy containing estrogen and progesterone
• Physical inactivity
• Not having children or having first pregnancy after age 30

These risk factors affect breast cancer development by influencing hormone exposure, cellular damage, or genetic susceptibility. Having risk factors doesn't mean someone will definitely develop breast cancer, but regular screening is important, especially for those with multiple risk factors.

Screening Recommendations

Mammograms are typically recommended starting at age 40-50, depending on individual risk profile, with more frequent or earlier screening for high-risk individuals, as suggested by the American College of Radiology 1. The most recent study 1 emphasizes the importance of breast cancer risk assessment by age 25, allowing elevated-risk patients to benefit from earlier and more aggressive breast cancer screening regimens. It is essential to consider both the benefits and risks of breast cancer screening and supplemental screening to assist patients in making informed decisions regarding their health care, as recommended by the American College of Radiology 1.

From the Research

Risk Factors for Breast Cancer

• Genetic predisposition, particularly mutations in the BRCA1 or BRCA2 genes, is a significant risk factor for breast cancer 2, 3, 4, 5, 6
• Family history of breast cancer, especially in first-degree relatives, increases the risk of developing breast cancer 2, 3, 5, 6
• Personal history of breast cancer or other cancers, such as ovarian cancer, also increases the risk of developing breast cancer 2, 5
• Other potential risk factors include:
  • Age: breast cancer risk increases with age 6
  • Hormonal factors: estrogen receptors (ERs) and HER2 signaling pathways play a role in breast cancer development 6
  • Epigenetic regulations and noncoding RNAs may contribute to breast cancer development and heterogeneity 6

Genetic Mutations and Breast Cancer Risk

• Mutations in the BRCA1 and BRCA2 genes are associated with an increased risk of breast, ovarian, and other types of cancer 2, 3, 4, 5
• Other genetic mutations, such as ATM, CDH1, CHEK2, PALB2, PTEN, STK11, and TP53, also confer breast cancer risk 3
• Genetic counseling and testing can help identify individuals with inherited mutations and inform risk-reducing strategies 2, 4, 5

Screening and Risk-Reducing Strategies

• Regular screening mammography and breast MRI can help detect breast cancer early in high-risk individuals 4, 5
• Risk-reducing mastectomy and salpingo-oophorectomy can decrease breast cancer risk in individuals with inherited mutations 2, 4
• Genetic counseling and testing can inform personalized risk management strategies and improve clinical outcomes 2, 4, 5