Breast Cancer: Risks and Prevention

Most of us know someone who has faced breast cancer. In the U.S., it’s the second most common cancer in women after skin cancer and the second leading cause of cancer deaths after lung cancer.

The good news is that outcomes are improving. When breast cancer is found early, the five-year survival rate is 99%. According to the American Cancer Society, deaths from breast cancer have declined steadily since 1989, thanks to earlier diagnoses, greater awareness and better treatments.

Breast Cancer Risk Factors

Every woman is at risk for breast cancer, but some factors raise that risk. One woman may have several risk factors and never develop the disease, while another may have none and still be diagnosed. That’s why mammograms are recommended for women over 45.

Known risk factors include:

Some of the currently known factors that can raise your risk:

• Being female and getting older: Two-thirds of invasive breast cancers are diagnosed in women over 55
• Childbearing history: Having no children by age 30 raises your risk
• Family history: Having a mother, sister or daughter with breast cancer doubles your risk. Two close relatives raise it about threefold.
• Genetics: Inherited BRCA1 or BRCA2 mutations raise lifetime risk to 45–80%.
• Hormonal history: Starting periods before 12 or reaching menopause after 55 increases risk
• Personal history: A prior breast cancer, dense breast tissue or chest radiation as a child or young adult increases risk

Some risk factors can’t be changed, but healthy lifestyle choices may lower your risk of breast cancer:

• Avoid certain hormone therapies after menopause. Long-term use of some estrogen-progestin treatments raises risk.
• Be active. Regular physical activity is linked to lower risk.
• Don’t smoke. Smoking may raise breast cancer risk and worsens outcomes after diagnosis.
• Drink alcohol in moderation. No more than one drink a day is recommended.
• Maintain a healthy weight. Obesity is linked to breast cancer, especially after menopause. 

Breast Cancer Screening Exams

Screenings are the best way to catch breast cancer early. Newer options like digital breast tomosynthesis, or 3D mammograms, improve accuracy, find more cancers and reduce false positives. 

Guidelines vary, but the American Cancer Society recommends yearly mammograms starting at age 40–45. Other organizations suggest beginning at 50. Because breast cancer in women in their 40s accounts for about 20% of cases — and can be more aggressive — it’s important to talk with your doctor about when to start.

If you have very high risk due to genetic mutations or strong family history, your doctor may also recommend regular breast MRI exams.