The official stages for breast cancer are Stages 0 through Stage IV, and each stage and subcategory of the stages has clearly defined features.
Another breast cancer Website had an article that mentioned Stage V in its title, but not in the article itself. After I pointed out the error to them, they indicated they would make a correction. (They also mentioned that some people "unofficially" talk about Stage V when there is nothing more that can be done except palliative treatment.) I also came across a Website for alternative/herbal tx that unofficial stage designation.
I don't think it is a good idea for people to "make things up as they go along" like that, because it tends to confuse people and to impede effective communication by deviating from the published and widely accepted stages used throughout the medical and survivor communities.
I do not know any of your previous history, and all you say is stage 5. Do you mean BIRAD 5 from a mammogram or ultrasound reading?
A BIRAD 5 conclusion by the Radiologist/surgeon who determined and wrote the biopsy readings is very concerning, and about as suspicious as can be for breast cancer.
Does this mean it's always and surely cancer? I don't think so but it's not good and most likely breast cancer.
Please keep us updated,