Mammograms miss about 30% of tumors in women younger than 50.
Mammograms miss about 17% of tumors in women older than 50.

A mammogram is the first line of defense against breast cancer since it can detect a tumor that is too small to feel.

The national cancer institute recommends that:

Women in their 40’s and older should have mammograms every one to two years.

Women who are at higher than average risk of breast cancer should talk with their health care providers about whether to have mammograms before age 40 and how often to have them.

Screening mammograms can often show a breast lump before it can be felt. They also can show a cluster of very tiny specks of calcium. These specks are called microcalcifications. Lumps or specks can be signs of cancer.