22 years ago I had DCIS. They couldn’t get clear margins so mastectomy. Sentinel nodes negative. I was 47. They wanted tamoxifen, I declined. Told no more mammogram in L breast. My new PCP ordered bilateral mammogram 3 weeks ago. Just under 1 cm tumor in my mastectomy breast. Await breast MRI results to see chest wall. Histology rated stage II. I did NOT take tamoxifen 22 yr ago. I am not one for regrets so I remain hopeful and incredibly grateful for getting to finish raising my 3 kids. I didn’t take tamoxifen because of the blood clot possible side effect. My pathology shows this cancer as 91% ER +. At age 70 I have several herniated disc and resulting arthritic pain so i am pretty negative on the side effects of hormone blockers. This sites chat has been really good. I will listen to radiologist but not convinced I will do it- more concern for side effects of chest wall radiation than about just breast radiation Lumpectomy will happen as soon as all the tests get done. I think my age gives me some leeway. My original surgeon told me I am in 2% range for this happening in mastectomy breast. She believes this is a new primary tumor. Oncology to be seen and weigh in. Best of luck to you.