Patient-reported outcome measures (PROMs) have been increasingly integrated into patient-facing technologies to engage and empower patients in cancer self-management at home. However, researchers and developers face several challenges in selecting the best-suited PROMs for patient-facing technologies, due to the complex nature of the disease, the multitude of PROMs with high psychometric quality, and the lack of clear standards for PROM utilization. In this paper, we have discussed these challenges, illustrated by breast cancer instruments.