Hi there Billy I have recently been diagnosed with the same but a larger tumour. Had PET CT and MRI scans. Tested for HER2 and was negative so chemo not required as yet. Booked in for mastectomy 12 June and then tests will be done to see if chemo will be required after the op. Have had previous breast cancer in the other side 5 years ago and had lumpectomy and 15 sessions of radiotherapy. Hope ll goes well for your sister