The prognostic value of radiologic extranodal extension in nasopharyngeal carcinoma: Systematic review and meta-analysis

Objectives: The prognostic value of radiologic extranodal extension (rENE) in nasopharyngeal carcinoma remains controversial. In this study, a meta-analysis was performed to assess the prognostic value of ungraded rENE and unambiguous advanced rENE. Methods: A literature search through PubMed, Cochrane Library, EMBASE and manual searches was conducted until May 2021. The adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of overall survival and distant metastasis-free survival were extracted and pooled. Results: Nine eligible studies were published between 2012 and 2021. The pooled patient number was 7532 (range 61-1887). Seven studies were eligible for the analysis of ungraded rENE, while 3 studies were eligible for unambiguous advanced rENE. The results showed that ungraded rENE was associated with worse overall survival (HR 1.85, 95% CI 1.04-3.27) and significantly associated with worse distant metastasis-free survival (HR 2.07, 95% CI 1.36-3.13). On the other hand, unambiguous advanced rENE was significantly associated with worse overall survival (HR 2.62, 95% CI 2.12-3.25) and worse distant metastasis-free survival (HR 3.14, 95% CI 1.85-5.33). Conclusions: In nasopharyngeal carcinoma, both ungraded and unambiguous advanced rENE are significant prognosticators of overall survival and distant metastasis-free survival. More prospective studies are required to determine its role in risk stratification or clinical staging.