ESTRO 2025 - Abstract Book

S1097

Clinical – Head & neck

ESTRO 2025

Aim : To correlate pDOI with occult nodal metastasis, nodal stage and to establish the correlation between rDOI and pDOI in patients of OCSCC.

Material/Methods: This is a retrospective observational study that analysed patients of oral cavity squamous cell cancer treated with radical intent from January 2017 to December 2021. Out of 560 analysed patients, 342 patients were found suitable for assessment and were included in this study. Results: Mean age of cohort was 55 years with male: female ratio of 6:1. Most common site of primary was buccal mucosa in 41.5% followed by tongue in 33% cases. 43% patients were clinically N0 at presentation, however, out of these 30.4% patients were found to have occult pathological nodal metastasis. In clinically N0 patients DOI (≤10mm vs > 10mm) was significantly correlated with finding pathological nodes (p < 0.0003). Patients with pDOI > 10mm had twice the incidence of pN3B nodes. DOI assessed by two radiologists was <5mm in 7.7% and 5.3%, was between 5-10mm in 34.1% and 32.62% and > 10mm in 65.1% and 66.8%. pDOI was <5mm in 6.96%, 5-10mm in 37.3% and >10mm in 55.7% cases. A strong correlation between pDOI with rDOI-1 (p-value < 0.0001) and rDOI-2 (p-value < 0.0001) was found. Furthermore, there was also a strong correlation between rDOI-1 and rDOI-2 (p-value<0.0001). Conclusion: Our study demonstrates that DOI serve as an indicator for biologically aggressive tumors and significantly correlates with presence of occult nodes and higher stage of nodes. Furthermore, when comparing pathological and radiological DOIs, no significant discrepancies were found, indicating that rDOI can be used as a surrogate for pDOI. Thus, rDOI can assist us in planning surgery and radiation in patients of oral cavity cancers.

Keywords: OCSCC, DOI, Radiological DOI

References: Bray F, Laversanne M, Sung H, et al. Global cancer statistics 2022: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin . 2024; 74(3): 229-263. Ali K, Sethi A, Islam NM, John D, Naseeruddin K, Alqaderi HE, et al. Evaluation of depth of invasion and tumor thickness as a prognostic factor for early-stage oral squamous cell carcinoma: a retrospective study. Diagnostics (Basel). 2022;12(1):20. doi:10.3390/diagnostics12010020

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Digital Poster Comparison between T1-, T2- and T1 StarVibe-weighted MRI and contrast-enhanced CT based delineation of organs at risk in head and neck radiotherapy Adelina Brezae 1,2,3 , Gaber Plavc 4 , Chiara Casale 5 , Gizem Temiz 6 , Nikos Paragios 7 , Eric Deutsch 8 , Frank Pilleul 9 , Riccardo Dal Bello 10 , Panagiotis Balermpas 10 , Vincent Grégoire 1 1 Department of Radiation Oncology, Centre Léon Bérard, Lyon, France. 2 Claude Bernard University, Claude Bernard University, Lyon, France. 3 Clinical Affairs, Therapanacea, Paris, France. 4 Department of Radiation Oncology, Institute of Oncology Ljubljana, Ljubljana, Slovenia. 5 Department of Oncology, University of Torino, Torino, Italy. 6 Department of Radiation Oncology, Therapanacea, Paris, France. 7 AI Engineering, Therapanacea, Paris, France. 8 Department of Radiation Oncology, Institut Gustave Roussy, Villejuif, France. 9 Department of Radiology, Centre Léon Bérard, Lyon, France. 10 Department of Radiation Oncology, Zurich University Hospital, Zurich, Switzerland