Mammograms are probably the most important tool doctors have to help them diagnose, evaluate, and follow women who've had breast cancer. Mammograms don't prevent breast cancer, but they can save lives by finding breast cancer as early as possible.

A mammogram is an X-ray test of the breasts (mammary glands) used to screen for breast problems, such as a lump, and whether a lump is fluid-filled (a cyst) or a solid mass.