Importantly, clinical registries may provide data on long-term outcomes occurring after the study period of a trial. They are more practical than randomized controlled trials, require fewer resources, and have less stringent inclusion and exclusion criteria for patient enrolment. Finally, clinical findings from registries have even more significance when patient-populations derive from different geographic areas, with heterogeneous referral pathways, baseline clinical characteristics, and perioperative treatment strategies. All these features substantiate the concept of "a real world practice" underlying any "registry-study".