BARCELONA, Spain - Up to a third of breast cancer cases in Western countries could be avoided if women ate less and exercised more, researchers at a conference said Thursday, renewing debate about how lifestyle factors affect the disease.
Better treatments, early diagnosis and mammogram screenings have dramatically slowed breast cancer, but experts said the focus should now shift to changing behaviors like diet and physical activity.
"What can be achieved with screening has been achieved," Carlo La Vecchia, head of epidemiology at the University of Milan, said. "It's time to move on to other things." La Vecchia spoke Thursday at a breast cancer conference in Barcelona. He cited figures from the International Agency for Research on Cancer, which estimates 25 to 30 percent of breast cancer cases could be avoided if women were thinner and exercised more.
His comments are in line with recent health advice that lifestyle changes in areas such as smoking, diet, exercise and sun exposure can play a significant role in risk for several cancers.
A woman's lifetime chance of getting breast cancer is about one in eight. Obese women are up to 60 percent more likely to develop any cancer than normal-weight women, according to a 2006 study by British researchers.
Many breast cancers are fueled by estrogen, a hormone produced in fat tissue. So experts suspect the fatter a woman is, the more estrogen she's likely to produce, which could fuel breast cancer. Yet discussion of weight and breast cancer is considered sensitive because some may misconstrue that as the medical establishment blaming women for their disease.
The American Cancer Society says the connection between weight and cancer risk is complex. It says risk appears to increase for women who gain weight as adults, but not for women who have always been overweight.