Hi @MK24, Sounds like a similar situation to me, tumor left breast 15mm, no lymph nodes involved, e&p+ and HER- I opted for a double mastectomy with tissue expanders for reconstruction. I chose double purely to lessen the chances of it coming back in the other breast
I also weighed up whether chemo was worth it for a less than 1% benefit, as this type of cancer doesn't really respond to chemo. I have chosen to just do the hormone blocker pills (tamoxifen) for 5-10 years and chosen not to do chemo. For such a small benefit I personally thought it wasn't worth going through chemo. Everyone is different of course, good luck with your upcoming surgery journey.
