I am 78. I have stage 1C invasive lobular cancer possibly a secondary cancer from my stage 3c endometrial cancer 23 years ago. I am 7 weeks from my lumpectomy. 2 sentinel lymph nodes negative and clear margins. Have decided on proton beam radiation. It will be 2 weeks daily, partial breast radiation. Radiation oncologist said a 20% chance of recurrence if I didn’t do radiation and didn’t do AI, 10% chance if I did one or the other. OncotypeDx showed 4% recurrence risk at 9 years with AI. Radiation sounds like a better choice as my pelvic risk fracture is 30% due to the endometrial treatment and AI would decrease my BMD. Proton beam radiation, if applicable, has far fewer short and long term side effects. I will see!