It is not known why cancers occur. Some women are more likely to get breast cancer than others. You have never breast-fed a baby or you had your first child after age 30. You started your menstrual period very early or you went through menopause very late. Taking birth control pills and oral estrogen does not seem to increase the risk of breast cancer.
Most women find the lump themselves during a breast self-exam.
Usually the lump is painless and it may be difficult to feel at first. Sometimes the skin over the lump is dimpled or creased. There may be a bloody discharge from the nipple or the nipple may start to turn inward. Although most breast lumps are found by women during a breast self-exam, the cancer is sometimes discovered by doctors during routine physical exams or mammograms. A mammogram is a special x-ray of the breast to look for breast cancer.