Definition

Breast cancer that is diagnosed during the time between a regular screening mammogram that appears normal and the next screening mammogram. A “true” interval breast cancer was not present when the last screening mammogram was done. A “missed” interval breast cancer was present but missed when the last screening mammogram was read. Interval breast cancers tend to be larger, grow and spread more quickly, and have a worse prognosis than those found on screening mammograms. Researchers are studying interval breast cancer to learn how to identify women who may need more frequent mammograms or other screening tests for breast cancer.