Consolidating the Hyams grading system in esthesioneuroblastoma - an individual participant data meta-analysis

Esthesioneuroblastoma (ENB) is an uncommon primary sinonasal tumor which can extend intracranially. Exactly how to classify them pathologically still remains discrepant; the Hyams grading system, for example, has not been universally adopted. This individual patient data (IPD) meta-analysis aimed to investigate the prognostic implication of each Hyams grade on patient outcomes.

We accessed two electronic databases including PubMed and Web of Science. Raw patient data from potential articles were extracted. To examine the associations of various clinicopathological factors with the Hyams grades, we utilized Chi-square, t-test, and Mann-Whitney, as appropriate. Log-rank test and Cox regression analysis were used to elucidate the impact of the Hyams grades on recurrence-free survival (RFS), metastasis-free survival (MFS), and overall survival (OS) of ENB patients.

We included 33 studies with 492 ENB patients. We found significant associations of Kadish stages, Dulguerov stages, rates of recurrence, metastasis, and patient mortality with Hyams grade. Log-rank tests and Cox regression models demonstrated significant differences in RFS and OS of Hyams grade I - II, grade III, and grade IV patients. There was no statistical difference in RFS and OS of Hyams grade I and II. Radiotherapy was only effective in grade III - IV ENBs and chemotherapy showed no benefits to patients.

We verify that the Hyams grading system appears to be a reliable prognostic indicator to assess ENB patient outcomes. Consolidating the Hyams grading system into a three-tier system based on similar clinical outcomes of grades I and II may simplify this classification schema.