J.Jpn. Surg. Soc.. 127(2): 198-205, 2026

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Feature topic

BREAST CANCER SURGERY IN THE IMMUNE CHECKPOINT INHIBITOR ERA

The advent of immune checkpoint inhibitors (ICIs) has ushered breast cancer treatment into a new era. Traditionally regarded as a poorly immunogenic tumor, breast cancer was thought to respond minimally to immunotherapy. However, triple-negative breast cancer (TNBC) has shown higher sensitivity to ICIs due to abundant tumor-infiltrating lymphocytes (TILs) and elevated tumor mutational burden (TMB). The KEYNOTE-522 trial demonstrated that adding pembrolizumab to neoadjuvant chemotherapy significantly improved pathological complete response rates and event-free survival, establishing the efficacy of perioperative immunotherapy. ICIs are recognized as a key therapeutic option in TNBC, prompting a reevaluation of surgical strategies. Nonetheless, clinical challenges such as immune-related adverse events (irAEs), perioperative management, and treatment integration remain significant. Early detection and multidisciplinary management of irAEs are essential to ensure safety, requiring close collaboration among surgeons, oncologists, anesthesiologists, and pathologists. Moreover, developing personalized treatment strategies that integrate multiple immune biomarkers, such as PD-L1 expression, TIL density, and TMB, is crucial, with pathological data from surgical specimens providing valuable insights. In the ICI era, breast cancer surgery is evolving into a new paradigm that unites immuno-oncologic understanding with multidisciplinary care, aiming to achieve safer, more effective treatment systems and improved patient outcomes through ongoing clinical and translational research.

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