See your doctor if you notice anything at all.
Before you panic, however, keep in mind that most breast changes and lumps dont end up being cancereven if you get to the point of doing a biopsy. Nearly 80% of biopsies come back benign.
False alarms are especially common for women with fibrocystic changes, which can make the breasts feel thicker or lumpy, with symptoms that may change over the course of the menstrual cycle. In the meantime, your best course of action is to follow a screening regimen that includes regular mammograms, clinical breast exams, and breast self-exams.