Background and purposeThis study investigated whether scheduled adaptive radiotherapy (ART) improved delivered dose to organs at risk (OAR) in patients with locally advanced head and neck cancer treated with dose painting (DP). Materials and MethodsDelivered doses were estimated for 81 patients who were prospectively treated with DP+ART using deformable image registration between CBCT and the planning CT's.Three simulations were conducted, evaluating (1) a scenario without replanning (Sim noART ), (2) a scenario with ART at fraction 12 (Sim ART ), and (3) the clinical practice with ad hoc replanning (Sim delivered ).It was further evaluated whether selecting patients for ART using accumulated dose in the first 10 fractions (Df10) to the parotid glands and larynx would improve ART efficacy. ResultsIn Sim noART , 41% of patients had delivered dose deviations 3 Gy compared to the planned dose in any OAR, primarily in the parotid glands and larynx.No significant differences were seen between Sim noART , Sim ART and Sim delivered (P.10).Df10 predicted relevant changes upon completing treatment with AUC0.95.By selecting patients for ART using Df10, delivered dose significantly improved for the larynx (P.01). Conclusions
Leeuw et al. (Sun,) studied this question.