Reirradiation based on diffusion-weighted magnetic resonance imaging-guided dose- painting for locally advanced
Chao Tan1,2,3, Yuyi Li1,2,3, Xiaoyu Chen1,2
1Department of Radiation Oncology, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University/Hunan Cancer Hospital, Changsha, Hunan, China.
Introduction:
The effect of diffusion-weighted magnetic resonance imaging (DWI)-guided dose-painting intensity-modulated radiation therapy (DP-IMRT) on locally advanced recurrent nasopharyngeal carcinoma (NPC) remains unclear. This study aimed to compare the outcomes and toxicities of DWI-guided DP-IMRT in patients with locally recurrent NPC.
Methods:
In this prospective trial, 150 patients with locally advanced recurrent NPC were randomly assigned (1:1) to receive reirradiation with DWI-guided DP-IMRT (DWI group, n = 75) or conventional MRI-based IMRT (MRI group, n = 75). In the DWI group, DWI-guided gross tumor volume received escalation to 65.4 Gy/30 fx in 2.18 Gy per fraction, while in the MRI group, the planning target volume was irradiated at 60 Gy/30fx in 2.0 Gy per fraction. The trial was registered at Chictr.org.cn (ChiCTR2100052340) on October 24, 2021. Survival rates were compared, and multivariate analyses were conducted.
Results:
The median follow-up duration was 16 months. Compared with the MRI group, patients in the DWI group had better 18-month progression-free survival (PFS) 75.1% vs. 53.6%; P = 0.006), local recurrence-free survival (LRFS) (83.4% vs. 61.8%; P = 0.010), and locoregional recurrence-free survival (73.1% vs. 64.9%; P = 0.025). Grade 3-4 toxicities between the two groups showed no significant difference. Multivariate analysis revealed that DWI-guided DP-IMRT was an independent prognostic factor for PFS and LRFS.
Conclusion:
Compared with conventional MRI-based IMRT, DWI-guided DP-IMRT improved PFS in patients with recurrent NPC without increasing acute and late toxic effects.
