ESTRO meets Asia 2024 - Abstract Book

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RTT – Treatment planning, OAR and target definitions

ESTRO meets Asia 2024

The present data showed that compared with conventional CTV,the volume of CTV decreased significantly(P< 0.05) with individualized CTV, especially CTV1 volume(107.44cm 3 VS 68.83cm 3 , P< 0.001).And individualized CTV reduced the doses delivered to OARs generally, such as the brainstem, spinal cord, optic nerves,contralateral temporal lobe, contralateral inner ear, and contralateral lens(all P< 0.05).Besides,the dosimetric parameters of PTV of the two CTV delineation had no significant difference(P> 0.05).Comparison of dosimetric parameters among the three radiotherapy techniques is in progress.

Conclusion:

For eccentric NPC,individualized CTV was significantly superior to conventional CTV in terms of target volume and dose delivered to OARs.Comparison of dosimetric parameters among the three radiotherapy techniques is in progress.

Keywords: eccentric NPC,CTV,plan evaluation

References:

[1]Wu Zheng, et al.Characteristics of local extension based on tumor distribution in nasopharyngeal carcinoma and proposed clinical target volume delineation. Radiotherapy and Oncology.2023;183,109595.

[2]Sun Y, et al. Reduction of clinical target volume in patients with lateralized cancer of the nasopharynx and without contralateral lymph node metastasis receiving intensitymodulated radiotherapy. Head Neck.2016;38(S1):E468–E472. [3]An-Chuan Li, et al.Pathologic study of tumour extension for clinically localized unilateral nasopharyngeal carcinoma: Should the contralateral side be included in the clinical target volume? Journal of Medical Imaging and Radiation Oncology.2018;62(4),540–547. [4]Sanford NN, et al. Individualization of clinical target volume delineation based on stepwise spread of nasopharyngeal carcinoma: Outcome of more than a decade of clinical experience. Int J Radiat Oncol Biol Phys. 2019;103(3):654–68. [6]De-Huan Xie, et al. Individualized clinical target volume delineation and efficacy analysis in unilateral nasopharyngeal carcinoma treated with intensity-modulated radiotherapy (IMRT):10-year summary. Journal of Cancer Research and Clinical Oncology.2022;148(8),1931–1942. [7]Qiaoli Wang, et al. Comparison of Dosimetric Benefits of Three Precise Radiotherapy Techniques in Nasopharyngeal Carcinoma Patients Using a Priority-Classified Plan Optimization Model. Frontiers in Oncology.2021. [8]Shan Lu, et al. Dosimetric Comparison of Helical Tomotherapy, Volume-Modulated Arc Therapy, and Fixed-Field Intensity-Modulated Radiation Therapy in Locally Advanced Nasopharyngeal Carcinoma. Frontiers in Oncology.2021. [5]Wu Zhang, et al.Characteristics of locoregional extension of unilateral nasopharyngeal carcinoma and suggestions for clinical target volume delineation. Radiation Oncology.2022;17(1).

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