Significantly Improved Local Control With the Use of Cesium-131 Brachytherapy in High-Risk and Recurrent Head and Neck (HN) Cancers: Long-Term Results of a Pilot Study

Purpose/Objective(s): Recurrent, high-risk head and neck (HN) cancer patients experience poor local control and survival with the current treatment options such as external beam radiation, surgery or chemotherapy. Evaluation of the feasibility and efficacy of reirradiation using contemporary radiation techniques is limited. Recognizing the need for further investigation in these high-risk patients, we developed a pilot study of salvage surgery with adjuvant brachytherapy using Cs-131 implants. Here we describe the long-term outcomes of the novel use of Cs-131 brachytherapy with concurrent salvage surgery. Materials/Methods: Eligible patients were those with recurrent biopsyproven HN cancer after prior definitive RTor patients with a new squamous cell primary carcinoma (Stage III/IV) of HN arising within previously irradiated fields. The recurrence was defined as recurrent Stage III-IV, but surgically resectable. Patients underwent a gross total resection of the tumor with implantation of Cs-131 brachytherapy seeds. Radiation seeds were implanted at 0.5-1 cm distances, covering the tumor bed with 80 Gy at 0.5 cm. Rates of overall survival (OS), locoregional recurrence free survival (LRFS), and disease-free survival (DFS) were analyzed using Kaplan Meier analysis. Recurrence was evaluated by clinical examination and confirmed by contrast CT and/or FDG-PET. Rates of radiation-induced toxicity were analyzed according to the Radiation Therapy Oncology Group toxicity criteria. The radiation exposure to the radiation oncology team, surgery team and remaining staff was measured as a part of this study. Results: Between 2010 and 2013, a total of 19 patients were enrolled. The majority of histologywas squamous cell carcinoma (10/19). One patient had gross residual disease following surgical resection. With follow-up up to 44 months (median 15, range 1-44 months), 9 patients developed another recurrence or progression of HN cancer, including the patient who had gross residual disease after attempted surgery. In 5 of these 9 cases, the failure was locoregional and in 2 patients, it was isolated distant failure. One patient was found to have simultaneous locoregional and distant progression of disease. Median overall survival is 15 months and disease free survival is 12 months. The 6, 12 and 18month OSwas 77%, 71% and 45%. The 6, 12 and 18month LRFS was 69%, 62% and 52%. The 6, 12 and 18 month DFS was 61%, 48% and 40%. Two patients developed Grade 3 toxicity; all other complications were Grade 1-2 with no Grade 4 or 5 complications. The exposure rate with Cs-131 was found to be acceptable. Conclusions: Compared to prior literature, our study shows that use of concurrent Cs-131 brachytherapy achieves excellent rates of local control and survival. In addition, the implant related exposure to staff was minimal, and there was no grade 4 or 5 toxicity despite re-irradiation in most patients. Author Disclosure: A. Pham: None. S. Arora: None. A. Wernicke: None. D.I. Kutler: None. K. William: None. C. Marc: None. N. Dattatreyudu: None. K. Chao: None. B. Parashar: None.