SS 09 - Head and Neck 1: Highest-Rated Abstracts for Virally-Mediated Head and Neck Cancer
Presenter(s)
C. M. Hidalgo1, K. S. Rourk1, H. Q. Baratz1, D. G. Eyassu1, A. W. Bogan2, K. M. Van Abel1, S. H. Patel3, M. L. Hinni4, A. V. Chintakuntlawar5, A. L. Holtzman6, J. R. Janus7, Y. Zhao8, E. J. Moore1, D. L. Price1, S. C. Lester9, K. Price10, M. Neben Wittich9, D. J. Ma9, L. X. Yin1, and D. M. Routman9; 1Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, MN, 2Department of Qualitative Health Sciences, Section of Biostatistics, Mayo Clinic, Scottsdale, AZ, 3Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, 4Department of Otolaryngology, Mayo Clinic, Scottsdale, AZ, 5Division of Medical Oncology, Mayo Clinic, Rochester, MN, 6Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, 7Mayo Clinic, Department of Otolarynoglogy, Jacksonville, FL, 8Department of Medical Oncology, Mayo Clinic Florida, Jacksonville, FL, 9Department of Radiation Oncology, Mayo Clinic, Rochester, MN, 10Department of Medical Oncology, Mayo Clinic, Rochester, MN
Purpose/Objective(s): De-escalated Adjuvant Radiation Therapy (DART) of 30-36 Gy delivered over 2 weeks with weekly docetaxel was initiated starting in 2013 in a phase II study (MC1273) and subsequently evaluated in a randomized phase III trial (MC1675). DART was shown to have less patient reported and clinician assessed toxicity compared to standard adjuvant therapy and was offered as a standard of care after these studies’ completion. Herein is our initial report of the characteristics and outcomes of this off-study population in comparison to, and combined with, clinical trial populations. We hypothesize off-study DART resulted in similar excellent locoregional recurrence failure free survival (LRFFS), progression free survival (PFS), and overall survival (OS) as patients treated on trial. Materials/Methods: Demographics, clinical characteristics, and survival outcomes using Kaplan Meier analysis of patients with surgically resectable HPV(+)OPSCC treated with DART at a multi-site tertiary care center from August 2013-April 2023 were analyzed. Patients with history of prior head and neck cancer, pT0 or pT4 disease, positive margin, unknown HPV status, metastatic disease at presentation, synchronous primary tumors, receipt of induction chemotherapy, or any part of their treatment at an outside institution were excluded from analysis. Results: 281 patients were included for analysis:169 patients (60%) treated on-study, and 112 patients (40%) treated off-study. Median follow up was 4.1 years. Both groups were majority male patients (90%), with a mean age of 59 years, and no smoking history (63%). Pathologic T stage, nodal size, perineural invasion (19% vs 19%, p=0.43), lymphovascular invasion (20% vs 19%, p=0.15), and extranodal extension (ENE) (52% vs 56%, p=0.46) were similar between groups. Pathologic N stage was significantly different between on-study and off-study patients (pN1 88% and pN2 12% vs. pN1 96% and pN2 4%, p=0.01). 2-year on and off-study outcomes were similar: LRFFS (97% vs 95%, p=0.76), PFS (92% vs 92%, p=0.65), and OS (98% vs 99% respectively, p=0.41). Overall, including on and off-study, patients with pN1 disease had a 2 and 5-year PFS of 94% and 90%; pN1 ENE(-) patients 2 and 5 year PFS was 97% (95% CI: 93%-100%) and 94% (95% CI: 88%-99%) vs. pN1 ENE(+) patients 2 and 5-year PFS of 92% (95% CI: 87%-97%) and 87% (95% CI: 80-94%). Conclusion: In this large series of de-escalation, on and off-study DART patient selection and outcomes were similar except fewer pN2 patients were de-escalated off-study given the interim results of MC1675 showing worse outcomes for this population. pN1 ENE(-) patients treated with DART had excellent 2- and 5-year PFS of 97% and 94%, and this de-escalated treatment represents a new standard of care for pN1 ENE(-) patients. Prospective study is underway in DART 2 evaluating biomarker risk stratified treatment of pN1 ENE(+) patients.
