Experts: Third of breast cancer is avoidable

Up to a third of breast cancer cases in Western countries could be avoided if women ate less and exercised more, researchers at a breast cancer conference said Thursday - comments that could ignite heated discussions among victims and advocates.

Many breast cancers are fueled by estrogen, a hormone produced in fat tissue. So experts suspect that the fatter a woman is, the more estrogen she's likely to produce, which could in turn spark breast cancer. Even in slim women, exercise can help reduce the cancer risk by converting more of the body's fat into muscle.