Radiological risk factors for T2-T3 glottic carcinoma treated with (chemo)radiotherapy—a multicenter analysis

OBJECTIVES: In moderately advanced (T2-T3) glottic cancer, eligibility for organ-preserving surgery is limited by tumor extension into certain high-risk areas within the larynx that can be identified on preoperative imaging and serve as predictive factors for poorer outcomes. Their relevance in conservative treatment modalities, including (chemo)radiotherapy ([C]RT), remains unclear. The objective was to evaluate the impact of these predefined surgical high-risk zones in patients treated with (C)RT. MATERIALS AND METHODS: This retrospective study included patients with T2-3, N0-3, M0 glottic carcinoma treated with primary (C)RT and with available diagnostic imaging from three academic medical centers between 2014 and 2018. Imaging was scored for tumor involvement of high-risk areas. The 5-year rates of locoregional control (LRC) and disease-specific survival (DSS) were compared using the log-rank test and Cox proportional hazards model. RESULTS: Imaging from 180 patients (mean age, 68 ± 11 years, 154 men) was assessed, with 173 entering the risk factor analysis after excluding unreliable scans. Significant findings were observed in the anterior larynx: vertical anterior commissure involvement negatively affected LRC and DSS, while horizontal anterior commissure and anterior paraglottic space reduced LRC. Deep vocal muscle infiltration showed negative trends. In multivariable analysis, vertical anterior commissure infiltration retained a trend toward lower DSS. CONCLUSION: Involvement of the anterior commissure, particularly vertical extension, which is a known predictive factor from surgical studies, likely predicts poorer outcomes after (C)RT for T2-T3 glottic carcinoma. Involvement of the anterior paraglottic space and depth of tumor infiltration carry potential predictive value. KEY POINTS: Question Can radiological risk factors proven in surgically treated patients with T2-T3 glottic carcinoma also predict treatment failure in patients treated with (chemo)radiotherapy? Findings On multivariable analysis, vertical anterior commissure involvement showed a trend toward poorer disease-specific survival. Clinical relevance Our findings contribute to the search for harmonized prognostic factors across treatment modalities for glottic carcinoma and provide a basis for integrating these risk factors into staging and treatment counseling.