Second primary tumor

My mother had breast cancer 15 years ago (believe it was stage II, 0 nodes, treated with radiation and tamox). Biopsy of mass in same breast Monday is once again cancer - said to be a second primary. Don't know much else at this point. She is meeting with the surgeon next week and he may at that time have a bit more information from the biopsy. Here are my questions. I don't know how many nodes they took out last time to check but how do they do it on the same breast a second time. Also, are they able to do radiation a second time on the same breast. She had a lumpectomy the first time and will now have a mastectomy this time. Thanks for any input.