Impact of paranasal sinus invasion on advanced nasopharyngeal carcinoma treated with intensity‐modulated radiation therapy: the validity of advanced T stage of AJCC/UICC eighth edition staging system

Abstract

The aim of this study was to clarify the prognostic role of paranasal sinus invasion in advanced NPC patients. Data of patients (n = 295) with advanced NPC (T3/T4N0‐3 M0) treated with intensity‐modulated radiation therapy were retrospectively analyzed. Staging was according to the AJCC/UICC eighth edition staging system. Overall survival (OS), local recurrence‐free survival (LRFS), distant metastasis‐free survival (DMFS), and disease‐free survival (DFS) were calculated, and differences were compared between patients with and without paranasal sinus invasion. Multivariate analysis was used to identify the independent predictors of different survival parameters. Paranasal sinus invasion was present in 126 of 295 (42.7%) patients. Sphenoid, ethmoid, maxillary, and frontal sinus involvements were present in 123 of 295 (41.7%), 95 of 295 (32.2%), 45 of 295 (15.3%), and 0 of 295 (0%), respectively. All survival parameters were significantly better in patients without paranasal sinus invasion. When paranasal sinus invasion was reclassified as T4 instead of T3, all survival rates, other than LRFS (P = 0.156), were significantly better in the new T3 patients, and differences in all survival parameters remained nonsignificant between T3 with paranasal sinus invasion and T4 without paranasal sinus invasion patients (all P > 0.05). In multivariate analysis, paranasal sinus invasion was found to be an independent negative prognostic factor for OS, DFS, and DMFS (P = 0.016, P = 0.004, and P = 0.006, respectively), but not for LRFS (P = 0.068). Paranasal sinus invasion has prognostic value in advanced NPC. It may be reasonable to classify paranasal sinus invasion as T4 stage.

Impact of Paranasal Sinus Invasion on Oncologic and Dosimetric Outcomes in Nasopharyngeal Carcinoma Following Intensity-Modulated Radiation Therapy—Implications for Risk Stratification and Planning Optimization

“…Similar results were found by Cao et al (8). Another study showed that classification of PSI into T4 provided better distinction between T3 and T4 in all survival outcomes (18). Our study demonstrated the independent prognostic value of PSI after ruling out the confounding of T4 structures.…”

“…PSI is not rare in NPC. Previously reported incidence of PSI ranged from 16.0% (17) to 42.7% (18) in locally advanced NPC. However, most of studies included both T3 and T4 patients.…”

Paranasal sinus invasion suggested T4 classification of patients of nasopharyngeal carcinoma: A two‐center retrospective investigation

“…However, survival data were only obtained for 3 years in the study by Zhang et al, and all of the studies above used the seventh AJCC staging system. Wang et al 19 retrospectively analyzed 295 advanced NPC patients who underwent IMRT based on the eighth AJCC staging system. Patients without paranasal sinus invasion had better OS, LRFS, DMFS, and disease-free survival.…”

“…NPC with paranasal sinus invasion is considered T3 classification in the eighth edition of the AJCC staging system, whereas the Chinese 2008 staging system, which is widely used in southern China, defines it as T4 disease . There are limited studies about the prognostic value and staging classification of NPC with paranasal sinus invasion, especially in the IMRT era with the current AJCC staging system . Whether different types of paranasal sinus invasion should be classified as the same T classification is still controversial .…”

“…11,17 There are limited studies about the prognostic value and staging classification of NPC with paranasal sinus invasion, especially in the IMRT era with the current AJCC staging system. 11,14,15,18,19 Whether different types of paranasal sinus invasion should be classified as the same T classification is still controversial. 14,15,18 To our knowledge, previous studies involved single-center analyses, and no study has yet compared the prognosis of paranasal sinus invasion in T3 and T4 disease or the involvement of inner structures.…”