Objective:

To assess the impact of implementing an in-house automated volumetric modulated arc therapy (VMAT) planning script for patients with head and neck (HN) cancer.

Approach:

• Implementation and Validation: The automated planning script was implemented in April 2020. Validation involved comparing 10 auto-plans with 10 manual plans for dosimetric indices and clinical acceptability reviewed by five radiation oncologists.
• Clinical Evaluation: Dosimetric indices from 1000 HN patients treated between 2017 and 2023 (500 manual pre-implementation, 500 automated post-implementation) were compared using t-tests.

Key Findings:

• In validation, auto-plans maintained PTV D95% coverage (107.4% vs 107.3%) and similar global Dmax while reducing maximum doses to critical structures: brainstem (-5.1 Gy, p < 0.03) and spinal cord (-2.9 Gy, p < 0.03).
• In clinical evaluation, auto-plans achieved PTV D95% coverage and similar global Dmax, with significant reductions in doses to various organs at risk: brainstem (-3.6 Gy, p < 0.001), spinal cord (-2.1 Gy, p < 0.001), contralateral submandibular gland (-4.1 Gy, p < 0.04), ipsilateral parotid (-3.9 Gy, p < 0.04), oral cavity (-2.5 Gy, p < 0.04), cochleae (-2.4 Gy, p < 0.04), larynx (-2.0 Gy, p < 0.04), contralateral parotid (-1.5 Gy, p < 0.04), and maximum doses to the mandible (-2.9 Gy, p < 0.04) and lips (-2.3 Gy, p < 0.04).
• 94% of automated plans and 86% of manual plans were rated clinically acceptable, with a preference for 7 auto-plans.

Interpretation:

Automated planning improved organ-at-risk sparing without compromising target coverage or dose homogeneity, with high clinical acceptability.

Limitations:

• The study is limited to a single institution's experience, which may affect the generalizability of the findings.
• Long-term impacts beyond three years were not assessed.

Conclusion:

Automated planning demonstrated significant benefits in dosimetric outcomes for patients with head and neck cancer.