This clinical trial evaluates whether a three-dimensional (3D)-printed external breast prosthesis improves patient-reported outcomes (PRO) among breast cancer patients that underwent surgical removal of the breast (mastectomy) without surgical reconstruction. Breast cancer remains a significant health concern and often requires a mastectomy. While breast reconstruction is a common option following a mastectomy, some patients decide not to undergo it or are not candidates. An external breast prosthesis is worn on the outside of the body to replace the breast that was removed during the mastectomy. Traditional external breast prostheses may lack comfort and fit. A 3D-printed external breast prosthesis is customized to the patient using 3D imaging along with computer-aided design (CAD) to interpret the 3D imaging to develop and print a patient-specific external breast prosthesis. This may create a better fitting prosthesis which may improve PRO.