What do we expect from mammography-based screening for the high risk population?
Ideally it should have 100% sensitivity with no palpable interval cancers popping up between rounds of screening. The detected cancers should all be non-invasive, which means a cure rate approaches 100%. This is probably not realistic, especially for BRCA1 mutation carriers whose tumors tend to invade at a very early stage in their natural history, so we would want the invasive tumors to be no larger than 1 cm and always negative lymph nodes.
Screening mammography doesn’t perform quite that well in the general population and, unfortunately in the high risk population it performs even less well. In 3 studies specifically focused on mutation carriers, mammography missed half the cancers, DCIS was rarely found, and a high percentage of the invasive cancers were large and node positive.