Both my sister and I have had breast cancer and her daughter but we've been marked as a no as yet identified genetic risk. Of course all sisters are on high surveillance.
When my sister had breast cancer first diagnosed some 20 years ago it was standard to do CT scans and bone scans at least annually. Research revealed it was of no benefit for early detection of mets and just caused people terribke anxiety. My sister had 5 clear years. 3 months after surveillance ended she had rib pain. A ct scan revealed mets then. It wasn't visible any earlier.
Because of current...check if concerned...in the last 3 years I've had ct scans of back, whole body, abdo ultrasounds and shoulder mri. All cancer free...but evidence of degenerative disease. So the surveillance happens if you discuss any new health worries with your Dr and always remind them of bc history.