Newly diagnosed; Treatment order advice

It's a really personal decision but I agree with @onemargie, you need to listen carefully to the medical advice as every case is different.  I had hormone positive cancer, a mastectomy and axillary clearance. I could have had a partial mastectomy but couldn't see the advantage in saving just part of a breast, and my surgeon did feel that a mastectomy was a safer option, given my particular diagnosis. I have consulted with both my surgeon and my oncologist about any advantages in a further preventative mastectomy. Both can't see any particular advantage. I have no family history of cancer let alone breast cancer, I haven't a particularly worrisome gene,, the hormone positive was in one lymph node only (the ony affected lymph node) not the primary tumour. I also had a  lot of problems with a seroma and could reasonably have the same again. Statistically I am more likely to get cancer again in another part of my body than in my right breast. Five years on and clear to date. But it's really horses for courses. The otehr factor is your own emotional feeling - if you feel you will be perpetually worried, that's something to take seriously. But when in doubt you may wish to take one step at a time. Deal with the current problem first. You can make other decisions later. Best wishes.