Radiation Therapy Target Objectives For Tonsillar Cancer Treated with Unilateral Radiation Therapy - A Replanning Study From TROG 12.01
- Author(s)
- Osbourne, G; Devlin, A; Walsh, N; Hardcastle, N; Moore, A; Rischin, D; Kenny, L; Porceddu, S; Wratten, C; Macann, A; Jackson, JE; Corry, J; McDowell, L;
- Journal Title
- International Journal of Radiation Oncology, Biology, Physics
- Publication Type
- Online publication before print
- Abstract
- INTRODUCTION: Unilateral radiotherapy (URT) is an effective treatment strategy in selected patients with lateralized tonsil cancer. However, there is a lack of established planning guidelines for URT treatment leading to suboptimal optimization of contralateral and midline organs at risk (OARs). This study aimed to re-optimize URT plans to maximize sparing of midline and contralateral OAR's while maintaining target coverage, providing dosimetric guidelines for URT planning. MATERIALS AND METHODS: Treatment plan data for patients treated with URT on XXXX were re-optimized using Eclipse V16.01. All relevant midline and OAR contours were contoured to align with international OAR consensus guidelines. Treatment plans were re-optimized, aiming for maximal midline and contralateral sparing while maintaining XXXX protocol-mandated target coverage (GTV: D100%>95%; PTV: D95%>95%). A second re-optimisation was performed to align with NRG acceptance criteria (PTV: D95%>100%). RESULTS: All re-optimized plans achieved the XXXX and NRG protocol target volume coverage. Clinically meaningful reductions in dose to the pharyngeal constrictors (trial delivered plan vs XXXX re-optimized plan, median of mean dose, 48.5 Gy vs 37.4 Gy, estimated mean difference [ED] -9.5Gy, p<0.001), contralateral submandibular gland (14.9 vs 6.7 Gy, ED -11.0, p<0.001) and larynx (22.1 vs 12.1, ED -12.2, p<0.001). Improvements were also seen in contralateral parotid gland (9.2 vs 4.9, ED -5.0, p<0.001) and oral cavity (39.5 vs 35.9, ED -3.0, p<0.001), which were considered less likely to be clinically relevant. There was no increase in dose to the ipsilateral or contralateral mandible. CONCLUSIONS: The results of this re-optimization study provide planning guidelines to guide dosimetrists and radiation oncologists on achievable OAR sparing when delivering URT.
- Keywords
- Carotid Arteries / radiation effects; Head and Neck Neoplasms; Larynx / radiation effects; Mandible / radiation effects; Oropharyngeal Neoplasms; Pharynx / radiation effects; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Intensity-Modulated, Pharyngeal Neoplasms; Salivary Glands / radiation effects; Tonsillar Neoplasms; organs at risk
- Department(s)
- Radiation Therapy; Physical Sciences; Medical Oncology; Radiation Oncology
- Publisher's Version
- https://doi.org/10.1016/j.ijrobp.2025.12.058
- Terms of Use/Rights Notice
- Refer to copyright notice on published article.
Creation Date: 2026-01-23 11:58:24
Last Modified: 2026-01-23 12:00:54