ESTRO meets Asia 2024 - Abstract Book

S172

Interdisciplinary – Head & neck

ESTRO meets Asia 2024

The median lymph node yield was 81 in BND and 40 in UND, with a median of 4 positive nodes. The nodal regions most commonly involved with ECE were IB (80%), II (58%), and II (78%) for groups 1, 2, and 3, respectively. Adjuvant chemo-radiotherapy (RT) was administered in 103 (72.5%)with at least 5 cycles given for 56 (54.4%), while 12 (9.5%) received RT alone and 27 (19%) did not receive any adjuvant treatment{9 (6.3%) experienced recurrence within 6 weeks of surgery and 2 patients developed stroke}. The most common RT dose was 60Gy/30 fr in 91 (79.1%). At a median follow-up of 35 months, 58 (4.08%) experienced treatment failures. The failure pattern is depicted in Figure 1. Among patients who had local failures (LF), 24 (80%) were observed within the reconstructed flap or tumor bed, and in the infra-temporal fossa and/ or skull base in 6 (20%). Among Regional failures (RF), 20 (71.4%) occurred in dissected nodal levels, and 8 (42.1%) were seen at the same level as that of initial involvement with ECE. RF was observed in the undissected contralateral neck in 8 (28.6%) cases having group 1 primary. Survival outcomes are depicted in Figure 2. The 2-year LRC, DFS, and OS were 34%, 34%, and 39%, respectively. On Univariate analysis inferior 2-year DFS, LRC, and OS were associated with group 2 and 3 primaries, multiple pathological positive nodes with ECE, neck nodal involvement with ECE at level IV/V, non-cohesive pattern of invasion, postoperative positive surgical margin, non-recipients of adjuvant treatment, andoverall treatment time (OTT)of > 85 days. However, the presence of perineural invasion is associated with inferior LRC. Multivariable analysis revealed poorer 2-year LRC and DFS for neck nodal involvement with ECE at level IV/V and OTT of > 85 days. Inferior 2-year OS was associated with group 2 and 3 primaries, the non-cohesive pattern of invasion, and OTT of > 85 days.

Conclusion:

This study represents one of the largest investigations into the landscape of node positive oral cancer patients having ECE depicting a comprehensive pattern of failure and warranting a more aggressive local and systemic approach. Additionally, it offers valuable insights into the prognostic factors linked with ECE, thereby enhancing understanding of this clinical scenario.

Keywords: OralSquamousCellCarcinoma, Extracapsular Extension

199

Digital Poster

Comparing survival and recurrence patterns in locally advanced oral cavity squamous cell carcinoma

Kenneth Oguejiofor 1 , Shanmugasundaram Ramkumar 1 , Ali-Abbas Nabi 2 , Sanjay Jogai 3 , Karwan Moutasim 3 , Rabin Singh 4 , Sanjay Sharma 4 , Madan Ethunandan 4 , Ian S Boon 1 1 Department of Clinical Oncology, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom. 2 School of Medicine, University of Southampton, Southampton, United Kingdom. 3 Department of Pathology, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom. 4 Department of Oral and Maxillofacial Surgery, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom

Purpose/Objective: