Clinical advances and challenges in dose constraints for organs at risk in proton therapy: A systematic review of the last decade's literature

Proton beam therapy has demonstrated significant clinical efficacy across multiple malignancies, primarily attributed to its distinct physical dose deposition characteristics. However, clinical implementation remains constrained by resource limitations and accumulated experience, particularly regarding radiation tolerance thresholds for organs at risk (OARs). Unlike photon-based radiotherapy where consensus guidelines like QUANTEC have been established, standardized dose constraints for proton therapy require further validation. This systematic review synthesizes decade-long evidence from peer-reviewed literature and clinical guidelines, critically evaluating current understanding of OARs tolerance in proton therapy. The comprehensive analysis aims to inform clinical decision-making and protocol development for emerging proton therapy.