What role does estrogen play in breast cancer risk?
Estrogen and other hormones play an important role in breast cancer. Prolonged exposure to estrogen during a woman’s lifetime, such as from early menstruation or late menopause, is known to increase her susceptibility to breast cancer. Factors that appear to increase estrogen levels—including alcohol use, lack of physical exercise, a higher body mass after menopause, and obesity—are associated with higher breast cancer risk.