Mammograms may pose a particular risk to women with genetic mutations that predispose them to breast cancer. Bill Branson/National Cancer Institute hide caption

itoggle caption Bill Branson/National Cancer Institute

Radiologist Gerald Iba checks mammograms at The Elizabeth Center for Cancer Detection in Los Angeles in May 2010. Damian Dovarganes/AP hide caption

itoggle caption Damian Dovarganes/AP

An estimated 45,000 people took part in the Susan B. Komen Race for the Cure in Little Rock, Ark., in Oct. 2010. But after a controversy involving potential cuts to funding of Planned Parenthood earlier this year, participation in fundraising races has dropped. Brian Chilson/AP hide caption

itoggle caption Brian Chilson/AP

This illustration shows a device made by MammoSite used to deliver targeted doses of radiation as part of brachytherapy. Courtesy Radiological Society of North America hide caption

itoggle caption Courtesy Radiological Society of North America

Arlene Kalley and her daughter Leila, who support the use of Avastin for breast cancer, hold a banner outside the National Mall in Washington in June.

Terry Kalley/AP hide caption

itoggle caption Terry Kalley/AP