Does it have to be wearable? Wouldn't it be enough to have one at home for daily checks? Sure, it's an agressive cancer, but it's not acting that fast.
This is going to just increase false positives and unnecessary biopsies. This level of surveillance is not beneficial.
Edit: maybe for extremely high risk groups like it says in the article I guess, but the fact that they're explicitly testing it to detect noncancerous cysts (false positives) doesn't improve my confidence.
No one is going to get a biopsy after testing positive once. A positive test would mean you go to a doctor for a proper mammogram, THEN maybe a biopsy.
That's still an increased level of surveillance that is going against current recommendations. Unnecessary mammograms still result in unnecessary biopsies. You could use it for increased monitoring to detect growth I guess, but I doubt ultrasound is capable of that sort of resolution.