Breast cancer is often first suspected when a lump or a change is found in the breast or when an abnormal area is seen on a mammogram. Most of the time, these findings don’t turn out to be breast cancer. However, the only way to know for sure is through follow-up tests.

This section describes how breast cancer is diagnosed and the factors that affect prognosis and guide treatment. Mammography, Breast Ultrasound and Breast MRI Before Diagnosis If your mammogram or clinical breast exam shows something abnormal, you will need follow-up tests to check whether or not the finding is cancer.

Sometimes, breast cancer can be ruled out with a follow-up mammogram (also called a diagnostic mammogram), breast ultrasound or a breast MRI. However, if these tests show the finding might be breast cancer, you will need a biopsy.