What is the lifetime risk of breast cancer for women?

• A. 1 in 8
• B. 1 in 50
• C. 1 in 100
• D. 1 in 4

Answer: (A)

Lifetime risk means the chance that a woman will develop breast cancer at some point during her life. For women in the general population, that lifetime risk is about 12%, or roughly 1 in 8. This reflects the cumulative probability up to a typical end-of-life age, not the risk at any single age.

The other options don’t match this broad, lifetime estimate: about 1 in 50 (2%) or 1 in 100 (1%) are far too low for the overall population, while 1 in 4 (25%) is higher than what is typically seen in the general population. (Certain high-risk groups may have higher risks, but the standard lifetime risk for women overall is about 1 in 8.)