Agh, the decisions we have to make! Like Mel, I had a mastectomy and with no family history of cancer and the advice that any further cancer could occur as easily elsewhere in the body as my right breast, I have remained mono-boobed. Different advice, different outcome. I am quite large breasted and have had no back or neck problems but I do wear a prosthesis pretty well all the time. I realised when I got it (12 months after my mastectomy due to a persistent seroma - another factor in not having the other breast off without a strong reason) that I had been walking very slightly lop sidedly because of the lack of weight but the prosthesis sorted that all out. Best wishes whatever you decide.