Pathology concordance levels for meningioma classification and grading in NRG Oncology RTOG Trial 0539

Abstract

Background. With advances in the understanding of histopathology on outcome, accurate meningioma grading becomes critical and drives treatment selection. The 2000 and 2007 WHO schema greatly increased the proportion of grade II meningiomas. Although associations with progression-free survival (PFS) and overall survival (OS) have been independently validated, interobserver concordance has not been formally assessed. Methods. Once mature, NRG Oncology RTOG-0539 will report PFS and OS in variably treated low-, intermediate-, and high-risk cohorts. We address concordance of histopathologic assessment between enrolling institutions and central review, performed by a single pathologist (AP), who is also involved in developing current WHO criteria. Results. The trial included 170 evaluable patients, 2 of whom had 2 eligible pathology reviews from different surgeries, resulting in 172 cases for analysis. Upon central review, 76 cases were categorized as WHO grade I, 71 as grade II, and 25 as grade III. Concordance for tumor grade was 87.2%. Among patients with WHO grades I, II, and III meningioma, respective concordance rates were 93.0%, 87.8%, and 93.6% (P values