Since your sister evidently has seen her Physician about this finding and has been treated I would doubt that cancer would be a consideration. I would guess that the medication you mentioned might be an antibiotic to reduce the inflammation of the cyst. Pain is not a symptom of breast cancer when a palpable lump is the issue and cysts aren't a form of cancer. Regards .....
Hi,
Is the lump between her two breasts? Has she seen a dr? Who prescribed the medicine and what is it?
If you can answer those questions, I will try to offer more of an opinion. Others will also chime in as well, I'm sure.
Chris
Healingwell62
Breast Cancer Community Leader