Comparing Kadish and Modified Dulguerov Staging Systems for Olfactory Neuroblastoma: An Individual Participant Data Meta-analysis

Abstract

Objective To compare the Kadish and the modified Dulguerov staging of individual participants to determine the impact of stage and other prognostic factors on disease-free (DFS) and overall survival (OS). Data Sources Systematic review of EMBASE, MEDLINE, Cochrane Library, and CINAHL databases. Review Methods The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) was followed for this study. Articles including patients with olfactory neuroblastoma (ONB) staged with both Kadish and Dulguerov staging systems were reviewed. The raw data from eligible studies were requested to perform an individual participant data (IPD) meta-analysis. Results Pooled data from 21 studies representing 399 patients with ONB undergoing treatment with curative intent showed that increasing age, treatment with chemotherapy, and positive or unreported margin status portended worse DFS ( P < .05). Increasing stage for both Kadish and Dulguerov staging systems was prognostic for worse DFS and OS ( P < .05), with Kadish C representing a heterogeneous group with regard to outcome and corresponding Dulguerov T stage. Using the Akaike information criterion, the Dulguerov staging system had superior performance to the Kadish system for DFS (1088.72 vs 1092.54) and OS (632.71 vs 644.23). Conclusion This study represents the first IPD meta-analysis of ONB directly comparing the outcomes of Kadish and Dulguerov staging systems in patients treated with primary surgery. Both systems correlated with DFS and OS, with superior performance in the Dulguerov system. Furthermore, the Kadish C group represented a heterogeneous group with regard to outcomes after stratification by the Dulguerov system. Dulguerov T4 patients had the worst outcome, with most being approached with open resection.