A novel approach to current radiopharmaceutical study design to document the efficiency of177Lu-PSMA-radioligand therapy of metastatic prostate cancer is described in a proposed prospective, real-time, real-world audit of a large patient population worldwide. The NIGHTCAP (National Investigators Global Harmonisa-tion Theragnostics of Cancer of Prostate) Study will establish real-world evidence (RWE) of overall survival (OS) and quality of life (QoL) in patients undergoing routine177Lu-PSMA-radioligand therapy on harmonised compassionate patient-usage protocols throughout the world. Such long-term efficiency data will be contrasted with the short-term randomised controlled trial (RCT) assessments of efficacy predicated upon surrogate markers of survival outcomes, such as progression-free survival (PFS). The shortcomings of RCT evaluation of the clinical benefit of new anticancer agents are detailed in this review, which advocates RWE to determine efficiency. The real-time monitoring of QoL in the NIGHTCAP Study is independent of questionnaires, language differ-ences, or oncologist bias, and relies upon individual patient self-assessment by choice of one of five emoji which best reflects their mood each day.