PO102

Purpose This study aimed to assess the clinical efficacy and safety of Stereotactic ablative brachytherapy (SABT) for unresectable or inoperable head and neck cancers. Material and Methods This study retrospectively assessed the clinical data of 40 patients with unresectable or inoperable head and neck cancers treated with SABT from October 2016 to October 2021. The variables assessed were local efficacy, progression-free-survival (PFS) rate, overall survival (OS) rate, and radiological adverse effects. Results The median follow-up was of 34 months (range, 5-59 months), and PFS rate at 6, 12, and 24 months was 90.0%, 74.7%, and 66.3%, respectively. The median survival time was of 16 months [95% confidence interval (CI), 10.2-21.8 months] and the OS rate at 6, 12, and 24 months was 97.5%, 70.0%, and 34.6%, respectively. The results of the univariate analysis revealed that the type of pathology and GTV D90 were related to PFS rate (P<0.05). However, the type of pathology, GTV D90, age, and implantation site were related to OS rate (P<0.05). The results of the multivariate analysis revealed that the GTV D90 was related to PFS rate (P<0.05). The type of pathology and GTV D90 were related to OS rate (P<0.05). The evaluation of postoperative radiological adverse reactions revealed that seven cases (17.5%) developed grade I/II skin reactions, four cases (10.0%) developed grade I/II oral mucosal reactions, and no cases developed grade III or higher adverse reactions. Postoperative seed dislocation occurred in three patients with tongue cancer. Conclusions SABT has produced good local control and mild adverse reactions in the treatment of unresectable or inoperable head and neck cancers. Additionally, it is safe, feasible, minimally invasive, and has fewer adverse effects than other treatment modalities. This study aimed to assess the clinical efficacy and safety of Stereotactic ablative brachytherapy (SABT) for unresectable or inoperable head and neck cancers. This study retrospectively assessed the clinical data of 40 patients with unresectable or inoperable head and neck cancers treated with SABT from October 2016 to October 2021. The variables assessed were local efficacy, progression-free-survival (PFS) rate, overall survival (OS) rate, and radiological adverse effects. The median follow-up was of 34 months (range, 5-59 months), and PFS rate at 6, 12, and 24 months was 90.0%, 74.7%, and 66.3%, respectively. The median survival time was of 16 months [95% confidence interval (CI), 10.2-21.8 months] and the OS rate at 6, 12, and 24 months was 97.5%, 70.0%, and 34.6%, respectively. The results of the univariate analysis revealed that the type of pathology and GTV D90 were related to PFS rate (P<0.05). However, the type of pathology, GTV D90, age, and implantation site were related to OS rate (P<0.05). The results of the multivariate analysis revealed that the GTV D90 was related to PFS rate (P<0.05). The type of pathology and GTV D90 were related to OS rate (P<0.05). The evaluation of postoperative radiological adverse reactions revealed that seven cases (17.5%) developed grade I/II skin reactions, four cases (10.0%) developed grade I/II oral mucosal reactions, and no cases developed grade III or higher adverse reactions. Postoperative seed dislocation occurred in three patients with tongue cancer. SABT has produced good local control and mild adverse reactions in the treatment of unresectable or inoperable head and neck cancers. Additionally, it is safe, feasible, minimally invasive, and has fewer adverse effects than other treatment modalities.