Real-world evidence in Tokyo is confirming that pembrolizumab combined with chemotherapy before and after surgery delivers event-free survival rates in line with the landmark KEYNOTE-522 trial for early-stage triple-negative and estrogen receptor-low breast cancer. The study used a smaller cohort but targeted the same clinical question as the registration program. In the real-world dataset of 95 patients, reported event-free survival trajectories closely matched KEYNOTE-522 outcomes, supporting use of the regimen outside trial settings. The results add to the growing body of post-approval data that can influence payers and treatment committees when assessing whether trial efficacy translates to routine care. For manufacturers and clinicians, the practical message is that performance in real-world practice is holding up—at least in this initial validation snapshot.