Is full re-optimization necessary in adaptive radiotherapy for head and neck cancer? A systematic review of dosimetric and clinical outcomes

ABSTRACT

Anatomical changes during head and neck radiotherapy can impact dose distribution. Adaptive radiotherapy (ART) aims to address these changes, but the optimal strategy remains uncertain. To systematically evaluate whether the current evidence supports routine full re-optimization in ART for head and neck cancer by synthesizing dosimetric and clinical outcomes reported across different ART strategies. A systematic review was conducted according to PRISMA guidelines. Nine eligible studies evaluating ART strategies in head and neck cancer were included for qualitative synthesis. ART consistently improved target coverage and organ-at-risk sparing across diverse adaptive workflows. However, improvements in locoregional control, survival, toxicity, and quality of life were inconsistent across studies, and substantial heterogeneity existed in adaptation timing, imaging guidance, and planning target volume (PTV) margins. Current evidence demonstrates consistent dosimetric advantages of ART, but does not directly establish whether routine full re-optimization is necessary for all patients. Owing to the heterogeneity of ART strategies and limited direct comparative evidence, the optimal extent and timing of adaptive replanning remain uncertain and require further prospective investigation.