@mjmac

Welcome to Mayo Connect and glad you have found helpful.

I was in similar situation five years ago, tumor in one breast and one positive lymph node. I took part in study of taking AI for 6 months to shrink tumor, and it did shrink. I used that time to get as healthy as could prior to surgery. But was definitely ready to get cancer out when came time for surgery. I went for lumpectomy, and even the day before surgery I was questioning my decision.

I did genetic testing to make sure I did not have a genetic reason for cancer. I did not. My sister had similar diagnosis years before mine and had same surgery I did.

Surgery went well, removed tumor and two lymph nodes that were positive. Easy recovery. I then had chemo, radiation and AIs for awhile. Could not tolerate AIs, so no longer take. Was monitor by an oncologists for 5 year now just have mammograms and MRIs 6 months apart ordered by my primary. I have dense breast so that is why I do MRI in addition to mammograms.

You can never predict the future or if cancer will comeback. My oncologist told me surviral rate is same for both procedure. If I did a lumpectomy and cancer returned, he would just treat again.

Susan G Komen foundation has a page that talks about making this decision:
https://www.komen.org/breast-cancer/treatment/type/surgery/mastectomy-vs-lumpectomy/
Another article from Susan Komen foundation on genetic testing:
https://www.komen.org/breast-cancer/treatment/issues/genetic-testing-after-a-breast-cancer-diagnosis/
Each individual has to evaluate the options based on their situation.

Did you have genetic testing? It might have an impact on your decision.