ESTRO 2023 - Abstract Book

S988

Digital Posters

ESTRO 2023

PO-1234 Standardized radiological extranodal extension assessment and prognosis in oropharyngeal carcinoma

F. Hoebers 1,6 , A. Postma 2,3 , W. Palm 2 , L. Wee 4,5 , F. Wesseling 7,8

1 Maastricht University Medical Center, Department of Radiation Oncology, Maastricht, The Netherlands; 2 Maastricht University Medical Center, Department of Radiology and Nuclear Medicine, Maastricht, The Netherlands; 3 Maastricht University, School for Mental Health and Sciences, Maastricht, The Netherlands; 4 Maastricht University Medical Centre, Department of Radiation Oncology (MAASTRO), Maastricht, The Netherlands; 5 Maastricht University, Clinical Data Science, Faculty of Health, Medicine and Life Sciences, Maastricht, The Netherlands; 6 Maastricht University , GROW - School for Oncology and Developmental Biology, Maastricht, The Netherlands; 7 Maastricht University Medical Center, Department of Radiation Oncology , Maastricht, The Netherlands; 8 Maastricht University, GROW - School for Oncology and Developmental Biology , Maastricht, The Netherlands Purpose or Objective The prognostic role of radiological extranodal extension (rENE) in HN cancer has been confirmed in several but not all studies ( Huang, 2021 ). Reasons for this inconsistent finding includes low sample size of some studies, but it may also be attributed to differences in the definition of rENE and the inclusion of different grades of certainty in the diagnosis. The aim of this study was to investigate the prognostic value of rENE in node-positive oropharyngeal carcinoma (OPC) using a publicly available dataset, analyzed according to a standardized protocol ( Hoebers, 2022 ). Materials and Methods For this study we selected data from The Cancer Imaging Archive (“ TCIA ”), searching for HN Cancer and imaging and outcome. The opensource Montreal “Head-Neck-PET-CT” ( Vallières, 2017 ) dataset was identified and downloaded. The total TCIA dataset comprised of 300 cases with HNSCC. From this set we included only patients with node-positive OPC, treated by upfront definitive radiation/chemoradiation who had a contrast-enhanced (radiation-treatment planning) CT scan available. This resulted in 36 cases available for the current study. All CT-scans were scored for the presence of rENE by two experienced head and neck radiologists. The presence of rENE was assessed on a 3-item certainty scale (1=suspicious, 2=highly likely, 3=definitely) as described previously ( Panicek, 2016 ). For this study, only cases with certainty scores 2 or 3 were classified as rENE-positive (rENE+). rENE was scored according to different categories: Grade 1: nodal capsule invasion of a single node with ill-defined border(s), but confined to perinodal fat; grade 2: invasion through two or more inseparable nodes with effacement of internodal planes; grade 3: invasion beyond perinodal fat with invasion or encasement of adjacent structures. Results Median age of the 36 patients was 61.8 years; gender was male in 83% and female in 17% of cases. TNM-stage was stage III in 2 cases and IV in 34 cases. HPV-status was positive in 13 patients, negative in 7, and missing in the remaining 16. Treatment consisted of chemoradiation in 35 and radiation only in 1 patient. rENE was present (rENE+) in 10 cases (28%) and absent (rENE-) in 26 cases (72%). The types of rENE were: grade 1 in 4 cases, grade 2 in 3 and grade 3 in the 3 remaining cases. Mean follow-up was 50 months (range 12 -102). 5y-DFS was statistically significant different between rENE+ vs. rENE- cases: 50.0% vs. 80.0% (log rank, p = 0.038). 5y-OS was again statistically significant different between rENE+ vs. rENE- (70.0% vs. 95.7% (log rank, p = 0.023). There was no difference in survival according to HPV-status in this small dataset. In multivariate analyses, rENE was significantly associated with DFS (HR 3.91, p-value = 0.043), whereas T and N-status were not.

Conclusion Standardized assessment according to strict criteria identifies rENE as a prognostic factor in OPC. rENE could potentially be used to further refine the TNM staging system.

PO-1235 Dose-volume predictors of dysphagia after definitive radiotherapy in larynx and hypopharynx cancer

J. Sung 1 , J.H. Kim 1 , S. Ahn 2 , E. Chung 3 , B. Keam 4 , S.E. Hyun 5 , H. Wu 1 , J.H. Lee 1