ESTRO 2025 - Abstract Book

S1115

Clinical – Head & neck

ESTRO 2025

4106

Digital Poster The value of re-resection to achieve R0 status in HNSCC patients undergoing adjuvant chemoradiation – preliminary results of a monocenter study Erik Haehl 1 , Louisa Bolwin 1 , Xhesika Dece 1 , Sebastian N Marschner 1 , Kristian Unger 1 , Christoph Reichel 2 , Philipp Baumeister 2 , Claus Belka 1 , Franziska Walter 1 1 Radiation Oncology, University Hospital Munich, LMU, Munich, Germany. 2 Otorhinolaryngology, Head and Neck Surgery, University Hospital Munich, LMU, Munich, Germany Purpose/Objective: Tumor resection followed by adjuvant (chemo)radiation is a standard treatment for locally advanced HNSCC patients. If an oncologic R0 resection cannot be achieved, re-resection is typically recommended, despite a potential delay of adjuvant therapy. However, the oncological benefit of re-resection in the adjuvant setting remains unclear. This study aims to examine the influence of re-resection on oncologic outcome in a large cohort of HNSCC patients receiving adjuvant (chemo)radiation. Material/Methods: Patients undergoing adjuvant (chemo)radiation between 01/2005-12/2023 were included and patient data was collected with final follow-up currently pending. Thus far, of 887 adjuvant HNSCC patients, 55 patients with initial R1 resection and consecutive R0 re-resection were identified. Using the preliminary data, we conducted a propensity score matching with a one-to-one nearest-neighbor approach. Matching variables included age, gender, tumor localization and disease stage. Descriptive statistics were obtained for the matched cohorts. Kaplan-Meier-models with Log-rank-tests and Cox proportional-hazard analyses were conducted for local recurrence (LR) and overall survival (OS). Results: Of the 110 matched patients, 76% were male 24% were female, with a median age of 60 years (range 35-82). Oropharynx was the most common localization (53%) followed by Oral Cavity and Larynx (19% and 13%, respectively). 24% of patients had T3/4 tumors and 77% had nodal involvement. The matched cohorts were well balanced with no significant differences in age and sex distribution, tumor localization, T-stage and lymph node involvement (p values: 0.23, 0.65, 0.81, 0.97 and 0.54). Median time from initial diagnosis to start of adjuvant (chemo)radiation trended to be longer for the re-resected cohort with 72 days (range 35-182) and 64.5 days (range 39-753) for the initial R0 resected cohort (p=0,06). After completing adjuvant therapy, OS was not significantly different (HR=3.2, 95%-CI:0.86-11.9, p=0.08) between the re-resected cohort (2- and 5-year overall survival: 90.5% and 81.3%), and the initially R0 resected patients (2- and 5-year overall survival: 85.2% and 75.0%). 2-year local control was 94.5% for the re-resected cohort and 96% for the initially R0 resected patients (log rank test,p=0.33). The univariate Cox regression model did not show a significant difference between cohorts (HR=1.9, 95%-CI:0.52-6.6, p=0.34). Conclusion: In our matched pair analysis of our preliminary data, patients undergoing re-resection to achieve R0 status showed comparable oncological outcome compared with patients having initial R0 resections. These results conflict with retrospective literature reports showing worse survival, yet lacking adjustment for confounders. Our data support the common practice to recommend re-resection if R0 seems feasible.

Keywords: HNSCC, resection margin, adjuvant chemoradiation