I want to echo Martin's sentiments that overdiagnosis is a word that is very difficult to understand. The role of screening is to find the cancer. How to treat the cancer is a different aspect of the cancer. To determine which cancer will be biologically aggressive and will grow and kill the woman versus which cancer will not grow but will allow the woman to die of some other cause.... That's something we cannot tell based on imaging.
It's not really overdiagnosis. We have to figure out which cancer needs treatment and which doesn't. That's not part of the screening process.