Clinical outcomes after reirradiation with dose painting of recurrent or second primary head and neck cancer

Purpose Recurrent or second primary head and neck cancer (rsHNC) presents a radiotherapeutic challenge due to limited tolerance of previously irradiated tissues. These patients could benefit from dose painting (DP), which focuses on delivering maximal dose to areas of high tumor burden while respecting dose constraints to organs at risk. In this study, we compare clinical outcomes in one group receiving standard reirradiation with a group receiving 18F-fluorodeoxyglucose (FDG) PET/CT-guided DP. Methods Our standard reirradiation regimen is hyperfractionated radiotherapy (RT) of 1.5 Gy x 40 (60 Gy total dose). For DP, we defined two FDG-based prescription volumes receiving at least 65 Gy and 70 Gy. Thirteen patients receiving standard RT were compared with 10 DP patients. Toxicity was scored using CTCAE v3.0. Disease-related endpoints were locoregional control (LRC), disease-free survival (DFS) and overall survival (OS). Results The mean composite toxicity score was maximal at the end of RT, with varying patterns across the CTCAE items. No significant difference in toxicity was found between the groups except for dysphagia at 6 months, where the standard RT group had worse scores (p=0.01). No differences were found in LRC and DFS. Two-year OS was 50% in the DP group versus 15% in the standard group (p=0.04), although this may reflect higher comorbidity in the standard group. Conclusion DP of rsHNC did not increase toxicity compared with standard reirradiation. No evidence of improved disease control was found. However, DP may benefit selected patients, and future studies should focus on identifying these candidates. Clinical trial registration https://clinicaltrials.gov , identifier NCT02921581.