That’s the $64,000 dollar question @Anna15! Over 11 years ago, I was diagnosed with breast cancer, HER2+. In fact, it wasn’t the tumour that was HER2+ but the one malignant lymph node (several
looked suss, 17 went but only was was actually malignant). Given size, position etc, a mastectomy was recommended plus a year of Herceptin and then hormonal therapy ( I did ten years). In my case, my oncologist felt that I was as likely to get another cancer elsewhere in my body as in a remaining breast. So a single mastectomy. And so far, so good! I didn’t do reconstruction, use a prosthesis and am happy with that. While older than you, I was as conscious of my body as anyone but also not keen to remove any more bits without a very clear risk. One of the problems about stats is not knowing where you sit in the figures. I had a completely unrelated and common procedure a few years ago with a one in 10,000 chance of anything going wrong. I was it!! Speedily rectified but it’s made me wary of thinking that 95% is a sure thing or that 5% won’t affect me. The best you can do is talk further with your oncologist, and if you take the test, discuss the results and how best to
interpret them. Best of luck and best wishes for a rapid recovery whatever you decide.