Abstract B30: Locoregional control in laryngeal and hypopharyngeal cancer patients treated with radiotherapy using direct gross tumor volume to planning target volume expansion

Abstract

Abstract Purposes/Objectives(s): To evaluate clinical outcomes and patterns of failure using a direct gross tumor volume to planning target volume expansion in patients treated for laryngeal or hypopharyngeal squamous cell carcinomas. Methods and Materials: We performed a retrospective review of patients with laryngeal or hypopharyngeal squamous cell carcinomas treated between 2002-2017 with primary radiotherapy with or without concurrent systemic therapy. Patient and disease characteristics associated with disease control and clinical outcomes were analyzed by Cox proportional hazards regression and Kaplan-Meier analyses. Deformable image registration between imaging at the time of failure and the treatment planning scan was used to determine patterns of failure. Results: Seventy-nine patients with laryngeal or hypopharyngeal squamous cell carcinoma were identified with a median follow-up of 54 months among surviving patients. Overall survival at 5 years was 62.9% (95% CI: 51.1%-74.7%). Five-year primary tumor control was 71.6% (95% CI: 61.4%-81.8%) and regional control was 78.8% (95% CI: 68.4%-89.2%). A total of 28 patients experienced a locoregional recurrence, of whom 18 had treatment plans available. Of these, 89% (n=16) experienced failures that were 95% contained within the high-dose treatment volume. One patient failed in an intermediate-dose volume and 1 exhibited a marginal failure in the high-dose volume. There were no factors associated with overall survival or locoregional control on multivariate analysis. Conclusion: Management of patients with laryngeal or hypopharyngeal squamous cell carcinoma using definitive radiotherapy and a high-dose planning target volume created without a gross tumor volume to clinical tumor volume expansion resulted in high locoregional control, with the vast majority of failures occurring within the high-dose field. These data support prospective evaluation of this technique. Citation Format: Adam R. Burr, Paul M. Harari, Matthew E. Witek. Locoregional control in laryngeal and hypopharyngeal cancer patients treated with radiotherapy using direct gross tumor volume to planning target volume expansion [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; 2019 Apr 29-30; Austin, TX. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_2):Abstract nr B30.