(NEW YORK) -- It's long been suggested that women perform breast self exams just after menstruation, when the breast tissue is less swollen and hence lumps are more likely to be felt. The exact opposite is true however, according to Greg Anderson, founder and CEO of Cancer Recovery Foundation International.
"Particularly right after the period, you're going to find more false positives than at any other time. Really, it's the second half of the monthly cycle, before the period, known as the luteal phase, that you want to do a self-exam," he says. Overdiagnosis and overtreatment of breast cancer is a problem just getting recognized by the medical community, Anderson says.
In women 50 years old and younger, dense breasts lead to many false positives, he says. This is in part why the American Cancer Society recommends clinical breast exams only once every three years for women under 40. For women over 50, the chance of false positives is substantially lower, says Anderson.
Copyright 2011 ABC News Radio