Deciding on radiation or not

The statistic I was given today at my surgeons office was 40% recurrence without radiation and 7-10 % with radiation usually within the first 2 years after surgery. I am 67 years old. I do not want to have to have another surgery so I am seriously thinking about radiation. My lumpectomy was on the left side directly over my heart. I was told by a radiology technician that there is a technique of holding your breath to expand your lungs during the treatment. This increases the distance between the radiation and the heart. It’s a tough decision along with taking endocrine blockers for 5 years with low grade DCIS.

I just had a lumpectomy 5-3-23. Age 70. ILC, Invasive Lobular Cradinoma, 1.3 cm mass, Estrogen & Projestoren +, HER2-. Nothing found in lymph nodes. I am also, contemplating if I should have radiation. That seems to be the standard protocal, however, I have read studies with women over 65, radiation may not be necessary, but AI would be recommended. I have a second issue, as the cancer is in the left breast, and I also, have a pacemaker in same breast. If I decide on radiation, than I would need another surgery to move the pacemaker to the other side.
I am concerned about damaging the heart as well. I would like to know where you found the information on 3 out of 100 women will have recurrence without radiation. I look forward to hearing back.