부산대학교 도서관

Purpose: Nasopharyngeal cancer (NPC) has a higher prevalence of regional nodal metastasis thanother head and neck cancers; however, level IB lymph node involvement is rare. We evaluated thesafety and feasibility of level IB-sparing radiotherapy (RT) for NPC patients. Materials and Methods: We retrospectively reviewed 236 patients with NPC who underwent defini-tive intensity-modulated RT with or without chemotherapy between 2004 and 2018. Of them, 212received IB-sparing RT, and 24 received non-IB-sparing RT. We conducted a propensity score match-ing analysis to compare treatment outcomes according to IB-sparing status. In addition, dosimetricanalysis of the salivary glands was performed to identify the relationship between xerostomia and theIB-sparing RT. Results: The median follow-up duration was 78 months (range, 7 to 194 months). Local, regional, anddistant recurrences were observed in 11.9%, 6.8%, and 16.1% of patients, respectively. Of the 16 pa-tients with regional recurrence, 14 underwent IB-sparing RT. The most common site categorization ofregional recurrence was level II (75%), followed by retropharyngeal lymph nodes (43.8%); however,there was no recurrence at level IB. In the matched cohorts, IB-sparing RT was not significantly relat-ed to treatment outcomes. However, IB-sparing RT patients received a significantly lower mean ipsi-lateral and contralateral submandibular glands doses (all, p < 0.001) and had a lower incidence ofchronic xerostomia compared with non-IB-sparing RT patients (p = 0.006). Conclusion: Our results demonstrated that IB-sparing RT is sufficiently safe and feasible for treatingNPC. To reduce the occurrence of xerostomia, IB-sparing RT should be considered without compro-mising target coverage.