DWI-guided DP-IMRT and conventional MRI-based IMRT in head and neck squamous cell carcinoma: a comparative study

The impact of diffusion-weighted magnetic resonance imaging guided dose-painting intensity-modulated radiation therapy on head and neck squamous cell carcinoma remains unclear. Our objective aimed at comparing the outcomes and toxicities of DWI-guided DP-IMRT for HNSCC. Between June 2018 and November 2022, we conducted a retrospective analysis of 260 HNSCC patients. Among them, 126 received chemoradiotherapy using DWI-guided dose painting intensity-modulated radiation therapy (DWI group), and the remaining 134 underwent chemoradiotherapy using conventional MRI-based intensity-modulated radiation therapy (Standard group). In DWI group, DW-MRI-guided gross tumor volume (GTV) received escalation to 77 Gy/35 fx in 2.2 Gy per fraction, while in Standard group, the GTV of HNSCC was irradiated at 70 Gy/35 fx at 2.0 Gy per fraction. All patients received induction chemotherapy. Survival rates were compared, and multivariate analyses were conducted. The median follow-up duration was 23 months. Compared to conventional MRI-based intensity-modulated radiation therapy, DWI-guided dose painting intensity-modulated radiation therapy showed improved 2-year disease-free survival (75.2% vs. 63.8%; P =.011) and locoregional recurrence-free survival (75.9% vs.64.7%; P =.013). Overall survival did not show significant difference between DWI group and Standard group (P =.442). Grade 3-5 toxicities were similar between the two groups. Multivariate analysis showed that DWI-guided dose painting was an independent prognostic factor for DFS (HR 0.559, 95% CI 0.324-0.966, P =.037). DWI-guided dose escalation has a benefit in DFS for patients with HNSCC without increasing acute adverse events.