Comparing adaptive and dose redistributed radiotherapy to conventional radiotherapy in head and neck cancer - Quality of life results from the phase III ARTFORCE trial.

QoL outcomes were assessed at baseline, directly after radiotherapy and at 6-month, 1-, 2-, and 5-year follow up using the EORTC QLQ C30, EORTC QLQ HN35 and EQ-5D-5L. Linear mixed-effects models (LMMs) were used for longitudinal analysis including fixed effects for baseline QoL scores, trial arm, time, an interaction term between trial arm and time and random effects for patients.

In line with the primary results of the trial (ARTFORCE, NCT01504815), dose redistribution combined with scheduled treatment adaptation showed comparable QoL outcome to conventional radiotherapy. Overall, QoL was mostly determined by patients' individual baseline QoL and improved at 6 months of follow up. These results confirm that this dose redistribution strategy is a safe strategy to increase dose to tumor subregions.

142 out of 221 patients (64 %) filled out at least one QoL questionnaire and were included for analysis. QoL was overall comparable between trial arms, with exception of a significant increase in sticky saliva complaints at 1 year and decreased global health status at 2 years in cRT compared to rRT. In the majority of the other LMMs, patients' QoL was significantly associated with their baseline QoL values and initial QoL deterioration observed after treatment was followed by improvement throughout follow up.

This study compared patient-reported quality of life (QoL) between patients with head and neck cancer treated with either FDG/PET-guided dose redistribution with scheduled treatment adaptation (rRT) or conventional radiotherapy (cRT).