It’s a familiar paradox: When we screen more people more often for cancer, we don’t just help by finding life-threatening cancers sooner; we also hurt by giving some people with pre-cancers or low-risk cancers overly aggressive treatments.
When it comes to breast cancer, things are even more complicated. Doctors can screen for cancer. They can also screen for mutations in BRCA genes that put some women at much higher risk. (Women with a BRCA1 mutation have roughly a 60 percent chance of developing breast or ovarian cancer by age 70.)