"The results showed that most overdiagnosis occurred in older patients with biologically favorable, slow-growing tumors."
These tumors are ones that will not
become problematic 'go bad' for 15-20 years. These do not need treatment..... In addition they revised their thinking on which tumors were going to become 'problematic' (what a sanitary word for cancer diagnosis).
This is new thinking.
So maybe instead of blindly following what we have been told in the past, we look at what is now known.... This is called progress.