Surgery and/or radiation scars are often high on the chest wall which makes them difficult to disguise or hide. Nowadays, most T-shirts, bras, camisoles, etc. are cut low and often designed to be worn with multi-layers.
I haven’t found any mastectomy bras that come up high, but I have found a camisole that comes with a high neckline. It has several style options that are both practical and dressy. The mastectomy camisole was also designed to be worn over a bra.
This mastectomy camisole is extremely comfortable – it has stretch to the fabric. It was designed with input from many women who had undergone breast cancer treatment – women who know.