Hi!
I went for the lumpectomy/ radiotherapy option as, like you, the surgeon said I could go either way. He did favour the lumpectomy route as it’s less invasive, and has found that women may regret rushing into a mastectomy when it is not clinically necessary. I had a type of partial reconstruction ( MICAP flap) at the same time. The radiotherapy ( 5 sessions) was not an issue- takes a few minutes and I had a slightly pink boob for a couple of weeks. I’m happy with that decision. My boob is a bit wonky but looks normal in a bra/bikini/ swimsuit etc!
Good luck with your upcoming treatments!