The Tufts Tool https://www.tuftsmedicalcenter.org/ibtr/ helped me decide to undergo radiation therapy after lumpectomy for ER+ IDC. It is the only tool that I am aware of that shows radiation recurrence results for ipsilateral/same breast with or without hormone or chemo therapy. As my breast surgeon asked, what if you cannot tolerate an AI or tamoxifen? This tool indicated, as do research studies, that radiation can be more effective than an AI against at least same breast recurrence. From what I understand, a new primary or contralateral breast cancer may be better avoided with an AI, given that ER+ BC has a repeat risk of decades, not just 5 years. My ONCO DX score was an 8, which indicated relatively low risks for metastatic spread with or without hormone adjuvant therapy and no need for chemotherapy.