ESTRO 2024 - Abstract Book

S1285

Clinical - Head & neck

ESTRO 2024

months after RT.

Results:

There were 41 treatment failures, including locoregional alone (13), distant metastasis alone (24), and locoregional plus distant failures (4). Thirty-two (78.0%) relapses have been confirmed pathologically. The timing of first PET/CT examination ranged from 15 to 88 (median 70) days after RT. Abnormal lesions were detected in 36 (67.9%) patients at this time-point. Among these 36 patients, tumor relapses were confirmed immediately or several months later in 27 patients. A detection yield of tumor relapse for all 53 patients is 50.9%. We further analyzed the relapse detection yield according to different post-RT plasma EBV DNA levels. Fifteen of 16 patients (93.8%) with high (³ 50 copies/ml) EBV DNA and 12 of 37 patients (32.4%) with low (< 50 copies/ml) EBV DNA were shown tumor relapse (P<0.0001).

Conclusion:

PET/CT scan performed within 3 months after RT is a valuable tool in relapse detection for the NPC patients with persistently detectable EBV DNA one week after finishing RT. Stratification by post-RT EBV DNA level can further increase detection yield significantly.

Keywords: PET/CT, nasopharyngeal carcinoma, EBV DNA

1397

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Treatment outcomes comparison of posterior pharyngeal wall cancers from oropharynx and hypopharynx.

Rahul Patil 1 , Petr Daniel Kovarik 2 , Malcolm Jackson 1 , Charles Kelly 1 , Laura McKenzie 1 , Jakub Cvek 3 , Nick West 4 , Nicholas Willis 5 , Josef Kovarik 1 , Muhammad Shahid Iqbal 1 1 Northern Centre for Cancer Care, Clinical Oncology, Newcastle upon Tyne, United Kingdom. 2 Northumbria Specialist Emergency Care Hospital, Department of Trauma and Orthopaedics, Cramlington, United Kingdom. 3 University of Ostrava, Department of Oncology, Ostrava, Czech Republic. 4 Northern Centre for Cancer Care, Radiotherapy Dosimetry, Newcastle upon Tyne, United Kingdom. 5 Northern Centre for Cancer Care, Radiotherapy Physics, Newcastle upon Tyne, United Kingdom

Purpose/Objective:

Due to of rarity of posterior wall oro- and hypo-pharyngeal tumours, the outcome of the treatment of these sites has been published together. The purpose of this analysis is to determine and compare curative treatment outcomes with radiotherapy for patients with primary carcinoma of posterior pharyngeal wall at oropharyngeal level with that tumours at hypopharyngeal level.