“Replacing breast implants”

Cancer 17 years ago, mastectomies and reconstruction. No recurrence of cancer or problems with implants. However over the past 17 years I have lost more than 50 pounds and feel that now my breast size is not proportionate to the rest of my body. It is difficult to buy clothing that fits well because the top is always too tight.

Would it be feasible to have new implants? What would be a ballpark cost figure to do this, and would Medicare and my supplemental insurance (which is very good) be likely to approve the cost.