53 Reirradiation with Stereotactic Ablative Radiotherapy in Recurrent Nasopharyngeal Carcinoma

• Published in: Radiotherapy and oncology 2024-03, Vol.192, p.S90-S92
• Main Authors: Yilmaz, Melek Tugce, Yigit, Ecem, Kahvecioglu, Alper, Yedekci, Fazli Yagiz, Sari, Sezin Yuce, Cengiz, Mustafa, Ozyigit, Gokhan, Gullu, Ibrahim, Aksoy, Sercan, Yazici, Gozde
• Format: Article
• Language: English
• Subjects: Nasopharyngeal carcinoma; reirradiation; SABR
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/S0167-8140(24)00467-5

Local recurrence (LR) rates in nasopharyngeal carcinoma (NPC) following definitive radiation (RT) ± chemotherapy (CT) range from 7–15%. A prospective trial comparing endoscopic surgery and reirradiation in recurrent cases found that surgery improved survival in a carefully chosen group of patients with low-volume mucosal recurrence. However, the fact that the recurrent disease is mostly multifocal and infiltrative in nature makes a limited group of patients suitable for surgery. In this study, we aimed to report our stereotactic ablative radiotherapy (SABR) outcomes in cases diagnosed with recurrent NPC. The data of 83 patients who underwent SABR in our department between 2007 and 2022 with the diagnosis of local-regional recurrent NPC, which was unresectable or had surgical margin positivity after resection were evaluated retrospectively. The Kaplan-Meier method was used for survival analyses (IBM SPSS v.23). Patient, tumor, and treatment characteristics are presented in Table 1. The median age was 53 (range, 19-78). The median follow-up was 24 months (range, 3–151 months). The median interval between patients’ first and second RT's was 39 months (range, 4–238 months). The initial response evaluation following reirradiation found a complete response in 38%, a partial response in 40%, stable disease in 8%, and progression in 1%. In follow-up, LR developed in 20 patients (24%) and distant metastasis (DM) developed in 14 patients (17%). The most common sites of DM were the lung, bone, and liver. SABR provided 76% local control (LC). The 1- and 2-year overall survival (OS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) rates were 67% and 53%, 65% and 46%, and 62% and 49%, respectively. In univariate analysis, LRFS (60% vs. 34%, p=0.002) and DMFS (63% vs. 31%, p=0.007) rates were higher in patients with recurrent tumor volume ≤36 cc compared to patients with tumor volume >36 cc. Age (≤53 vs. >53 years), gender (male vs. female), interval between RTs (≤2 vs. >2 years), surgery before SBRT (yes vs. no), SBRT dose (≤30 vs. >30 Gy) and device (robotic- vs. linear accelerator-based), and site of recurrence (primary vs. neck recurrence) could not be identified for prognostic significance for OS, LRFS, and DMFS parameters. A notable proportion of patients experienced late toxicity, with 20% exhibiting grade 3 or 4 toxicity and 12% experiencing grade 5 toxicity. Fourteen patients (17%) experienced massive hemorrhage as a result of