Hi Kiwi- So sorry about your mother. I hope her lump turns out to be benign; if she gets as far as a biopsy, understand that about 85% of biopsies do indeed show a benign lump, so the odds are definitely with her.   Yes, finding a lump 9 months after a clear mammogram is quite a common experience, It takes a long time for most breast cancers to grow; by the time you can actually detect a lump, chances are the cancer has been growing for about 8 years. Your mother sounds like she was a on a regular mammogram schedule, and that's considered the best form of screening for early detection, so yes, I'd assume this would be considered early detection.   Best of luck to you both going forward. I hope the lump turns out to be a simple cyst. If not, stay in touch here - we can help. - PJH