2723 - Late Toxicity and Survival Outcomes Following Intensity-Modulated Radiation Therapy for Recurrent or Second Primary Squamous Cell Carcinomas of the Head and Neck
Presenter(s)
V. Chinnaiyan1, L. Zhang1, G. Q. Yang2, M. Echevarria2, N. Razavian2, and J. Caudell2; 1University of South Florida Morsani College of Medicine, Tampa, FL, 2H. Lee Moffitt Cancer Center and Research Institute, Department of Radiation Oncology, Tampa, FL
Purpose/Objective(s): While re-irradiation (re-RT) is a standard therapeutic approach for patients with locoregionally recurrent or second primary squamous cell carcinomas of the head and neck, it is associated with considerable late toxicities and suboptimal overall survival (OS). Herein, we present our institutional experience with intensity-modulated RT (IMRT) in this challenging treatment space.
Materials/Methods: In this retrospective series, an institutional database of patients who received re-RT for locoregionally recurrent or second primary squamous cell carcinomas of head and neck was queried. Patients included for analysis received re-RT using IMRT. Patient demographics, as well as prior and current tumor/treatment details, were abstracted from electronic medical records. Severe late toxicity (grade 3+), occurring at least 90 days after re-RT, was graded using the CTCAE (v4.0) criteria. Tumor control and survival outcomes, including LRC, PFS, and OS, were calculated from the end of treatment and analyzed via Kaplan-Meier method.
Results: A total of 237 patients who received IMRT for re-RT were identified and eligible for analysis. Among included patients, the majority were men (75.1%), former smokers (65%), and received re-RT for recurrent disease (70.5%). The most common sites of disease were the oropharynx (32.9%), neck (20.7%), oral cavity (14.3%) and larynx (10.5%). Among those tested, the rate of HPV and/or EBV positivity was 38%. At time of re-RT, median age was 63 years old (range: 37 - 92) and median Karnofsky Performance Status was 90 (50-100). The median tumor volume was 5.68 cc (1.0238 - 139.63 cc), and the median dose of reRT was 60 Gy (40 - 74 Gy). Concurrent systemic therapy was prescribed in 89% of patients. Median follow up of patients alive at last contact was 76 months. At 2-years post re-RT, LRC, PFS, and OS were 38.6%, 22.7%, and 36.8% respectively. At 5 years post re-RT, LRC, PFS, and OS were 30.5%, 13.7%, and 18.6%, respectively. Late grade 3 or greater toxicity occurred in 29.1% of patients.
Conclusion: While results of our institutional experience appear favorable compared to prior studies (RTOG 9610 and 9911), re-RT with IMRT approaches continues to have substantial late toxicity and suboptimal survival outcomes. Further work is necessary to improve the therapeutic window in this challenging clinical scenario.