A post-mastectomy bra has pockets to take prosthesis, of course, but that's not all. Some are designed to hide irregularities at the underarm; others are higher at the top to cover upper chest scars. Also important is that they are made from soft, breathable fabrics like moisture-wicking microfibre for comfort.
Whenever you try on a bra, make sure you try it with a prosthesis. If you have a prosthesis on one side, fit the other, intact breast first. If, on the other hand, you've had reconstructive surgery, fit the reconstruction first.
" As well as a specific post-mastectomy bra, a soft cup bra with high sides, a high centre gore and a stretchy upper cup can also accommodate a prothesis."