The U.S. assumed a benefit of screening, so they did not review evidence before 2016. They moved on. They found no new randomized control trials, much like we spoke to. These trials were all or primarily done a long time ago.
They assumed benefit and they had to look at other things. They looked at some non-randomized trials. They also looked at some modelling data, because we know that we cannot rely on the old trials. The old trials were done before digital mammography. They were done even before tamoxifen existed. We are talking about very rudimentary treatment.
These old trials only show a mortality benefit of 15%, compared to the 40% or 44% that we're hearing.
The other thing the U.S. looked at was the impact on minority groups and the younger age at diagnosis for Black and Asian women. The increasing incidence, the change in the different age of diagnosis and the modelling data are what prompted the change.