Long-Term Outcomes for Re-Irradiation of Recurrent Head-And-Neck Cancers: Mature Data from a Large Series

Abstract

Locoregional recurrence or second-primary cancer in previously irradiated head-and-neck cancer patients poses a therapeutic challenge. Fractionated Stereotactic Body Radiotherapy (SBRT) should be considered in the multi-disciplinary approach for these patients. We report our mature results with reirradiation using fractionated SBRT for head-and-neck cancer with and without complete macroscopic resection. From 2002 to 2016, 133 lesions in 123 patients received robotic SBRT to the oropharynx (n = 21), hypopharynx (n = 8), nasopharynx (n = 9), paranasal sinus (n = 7), neck (n = 39), and other sites (n = 49) including overlapping sites. Ninety-two lesions in 88 patients were treated definitively, and 41 lesions were treated with palliative intent. Thirty-six percent of lesions underwent complete macroscopic resection before SBRT. Seventy-eight patients received chemosensitization. The median initial radiation dose was 70 Gy, and the median reirradiation SBRT dose was 30 Gy (21-42.5 Gy) in 2-5 fractions. Overall survival (OS) and locoregional control (LRC) were determined using the Kaplan Meier method. Cox regression analysis was used to determine predictors of LRC and OS. The median follow-up for surviving patients was 24.2 months following re-irradiation. Median OS for all patients was 12 months. For definitively treated patients, the 2-year OS and LRC rates were 42% and 36%, respectively. Durable local control was achieved in 56% of all patients. For these patients, median and 2-year OS were 24 months and 51%. Of those who were not a candidate for complete macroscopic resection, 54% achieved durable local control with radiotherapy. Median and 2-year OS were 15.8 months and 31%. Multivariate analysis demonstrated that higher total dose and surgical resection were significantly associated with improved LRC; durable local control and younger age were associated with improved OS. SBRT reirradiation for recurrent or second-primary head-and-neck cancer remains an important part of a multidisciplinary approach for these challenging cases. This study demonstrates encouraging response rates even in patients who are not ideal surgical candidates. The role of SBRT reirradiation in the era of immunotherapy utilization warrants further study.