bleeding can indicate cancer but usually its just the one side that bleeds spontaneously. it would be v unlikely with both of them. it may be that she was prone to having cycts or something developing in the ducts.
Since a biopsy was evidently not done it will be the Pathology report that will give a definite answer to your question. It would be unusual to have a cancerous condition involving both breasts. Wishing your daughter an uneventful procedure and a speedy recovery.