I think it does rely on the pathology of your cancer....these days I'm of the understanding they like to conserve as much breast as possible, which is fair i suppose...BUT like you said alot of women have had the cancer return in the healthy breast left behind...I never had that dilema....It was pretty much decided for me, based on my cancer, tumour size, stage, node involvement etc and the fact that they would never be able to match my HH sized boob, even with a reduction to match the reconstructed one....so i had a bi lateral mastectomy with expanders after chemo....
I find it weird how when you have cancer they say no to bi lateral....yet some will do 'preventative' mastectomies? Good luck