Sorry to hear about your daughter's complaints. The symptoms are certainly not suggestive of cancer. The commonest cause of bloody discharge in young girls is a duct papilloma
. This is not a cancerous condition but a small growth which sloughs off and produces bloody discharge. Sometimes it is so small, that it cannot be picked up on scans or physical examination. The only way to diagnose it is to send the bloody discharge for cytological examination or do a ductoscopy. If it is diagnosed, it can be treated by a minor surgical procedure.
You should seek the advise of a breast surgeon at the earliest.
Hoping for the best.
Dr. Rohan Khandelwal