Key issues of treatment for patients with breast cancer such as patient satisfaction with treatments, compliance, and some side effects are essential for evaluating quality of life by patient-reported outcomes in clinical trials. The study aimed to develop and evaluate a specific patient-reported measure which included physical, psychological, social, and therapeutic domain for assessing the survival of patients with breast cancer.The pool of items was drafted after a theoretical revision and cognitive interviews with women with breast cancer. The draft scale was formed after the adjustment of the items and dimensions, and the selected items were submitted to expert's judgments. Five statistical methods were used to select these items by 2 validation samples. The final scale was administered to a sample of 417 patients from 8 hospitals and 135 controls for reliability, validity, and responsive analyses.The final BC-PROM consisted of 52 items, 13 subdomains, and 4 domains, being developed after preexamination and formal examination. Cronbach alpha coefficient was 0.902 and 0.712 for the full scale and therapeutic domain. The structural validity results showed that the multidimensional measurement of the scale fulfilled expectations. Differences in the BC-PROM mean scores were significant between cancer patients and healthy participants in 13 subdomains (P < .05), indicating good responsiveness. Among the sample survey of patients, the scale copy acceptance rate was 98.2%, completion rate 94.6%, and average filling time 10 minutes.The new and reliable BC-PROM was developed in patients with breast cancer and applied to clinical treatment evaluation and clinical trials for such patients.