In all honesty, @Xyzabc - my own personal belief would be that mastectomy (particularly if you intend to have reconstruction at a later date) would be worse than radiotherapy - as it is much more intensive surgery & recovery, involving drains & other things. Lumpectomy - sometimes it can just be day surgery, altho most usually stay in overnight (I did) to see the surgeon the next morning.
What type of cancer has it been diagnosed as? Lobular? or Ductal?
With my surgery being around the nipple, I had my radiotherapy 'face down' (boob hanging thru a hole and targeted from underneath) so there was no chance of the radiotherapy impacting other organs ..... is yours on the right or the left boob?
There is also the 'mental' element to mastectomy & reconstruction as well ..... not all end up as 'pretty' as hoped, I am afraid, with some having multiple surgery ... but that is the risk you have to take, with the more intensive surgery.
I can send you some pics of mine if you like (private message) so that you can see how it 'could be' with lumpectomy, as they've indicated yours will be minimal scarring ....
We've all grappled with that question .... which ever way you go - YOU have to be happy with the decision. xx