ICHNO-ECHNO 2022 - Abstract Book

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ICHNO-ECHNO 2022

as is data including immune checkpoint inhibitors (ICI). We sought to assess patterns of failure and overall survival in patients treated at our institution, as well as outcomes with respect to concurrent treatment regimen. Materials and Methods We retrospectively identified patients with locally advanced (AJCC 8 th ed., stage III-IVb) hypopharyngeal or laryngeal carcinoma who presented to our institution for definitive RT between 2012 and 2017. Patients who underwent primary resection or with synchronous metastases were excluded. Age at diagnosis, primary site, stage, 1- and 3-year OS, locoregional failure (LRF), distant failure (DF), laryngectomy free survival (LFS), RT dose, and concurrent systemic regimen (ST) were recorded. ST was stratified into platinum based (PLT), cetuximab based (CTX), or ICI (anti-PD-1/CTLA-4) inclusive (ICI); ICI was co-administered with PLT or CTX on-trial. Data was analyzed in SPSS v27.0 (IBM, Armonk, NY); OS, LFS, and time to LRF/DF were assessed via Kaplan-Meier, with the log-rank test used to assess differences in outcomes between chemotherapy regimens. Results We identified 65 patients treated with definitive radiotherapy, with a median follow up of 4.33 years and 78.5% presenting with stage IV disease. Primary disease sites represented were supraglottic (n=29), glottic (n=18), hypopharyngeal (n=12), pyriform sinus (n=4), and subglottic (n=2), with 80.0% receiving ≥ 70 Gy RT to gross disease. A majority received either PLT (n=28, 43.1%) or CTX (n=19, 29.2%) ST, with a significant cohort (n=15, 23.1%) receiving ICI (n=9 with cisplatin, n=5 with cetuximab, n=1 as monotherapy). Total failure rate was 40.0%, with 16.9% of patients experiencing DF, 13.8% experiencing LRF, and 9.2% experiencing both LRF and DF. 86.2% of patients were alive with 80% LFS at 1 year, and 73.6% were alive with 62.4% LFS at 3 years. ST significantly impacted LFS (p=0.003) and OS (p=0.006, Figure 1), with 1-year OS of 96.4% (PLT), 68.4% (CTX), and 86.7% (ICI), and 3-year OS of 78.5% (PLT), 47.4% (CTX), and 80.0% (ICI), and LRF (p=0.026, Figure 2), with 1-year LRF of 3.6% (PLT), 36.9% (CTX), 14.4% (ICI), and 3-year LRF of 7.8% (PLT), 39.2% (CTX), and 30.0% (ICI). ST demonstrated a weak trend on DF (p=0.099).

Conclusion Local and distant failure rates are similar in patients receiving definitive RT for locally advanced laryngeal and hypopharyngeal carcinoma. ST regimen impacted OS, LFS, and LRF without significantly impacting DF. Concurrent