In Reply: Transcriptomic Profiling Revealed Lnc-GOLGA6A-1 as a Novel Prognostic Biomarker of Meningioma Recurrence.

Abstract

To the Editor: We read with great interest the letter to the editor by Dr Wang titled “Letter: Transcriptomic Profiling Revealed Lnc-GOLGA6A-1 as a Novel Prognostic Biomarker of Meningioma Recurrence”1 and are deeply appreciative of his interest in our study.2 The extent of surgical resection is among the most important predictors of meningioma recurrence.3,4 In our retrospective study, the extent of resection was evaluated using the Simpson grade (SG) scale,5 which has been widely used to grade meningioma resection since 1957. Total resection, defined as removal of the whole tumor along with the attached dura mater and potentially affected bone, is unfeasible in many patients because of a high risk of brain injury, disrupting the blood supply to the central nervous system or simply because the lesion's location is inaccessible.6 The SG scale5 was therefore introduced into clinical practice as a parameter describing the extent of meningioma resection, which can be determined either intraoperatively by the surgeon or postoperatively by follow-up imaging. SG I denotes total resection and is associated with the lowest probability of recurrence. SG II-III denote gross total resections with the tumor itself removed completely but dura mater left in place with (SG II) or without (SG III) coagulation. SG IV denotes incomplete resection of the tumor, with a risk of recurrence almost 5 times higher than for SG I. Finally, SG V indicates that only a biopsy and/or decompression of the affected area were performed.7 MRI is used at most centers for accurate preoperative, intraoperative, and postoperative patient management, including assessing the extent of meningioma resection. A recent publication reported high concordance between SG classification and MRI assessment of tumor resection (up to 75%).8 Moreover, in prognostic value, the difference between SG IV and SG I-III is more significant than any other difference between SG categories, and SG IV resections are readily distinguished from those of lower grades through intraoperative assessment by a neurosurgeon. Consequently, despite the clear value of postoperative MRI for assessing the extent of resection, it is clear that clinically useful assessments can be obtained using the SG scale alone. Intraoperative MRI is also a powerful tool but can be problematically time consuming, and its practical utility may be limited by technical and economic factors, especially because it should ideally be applied in conjunction with other imaging methods and molecular analyses.9 However, perhaps the most important point relating to our study and Dr Wang's comments is that the inherent limitations of retrospective studies mean that evaluations based on follow-up MRI imaging are often simply unavailable in studies analyzing the prognostic and predictive value of novel genomic or proteomic biomarkers using archived tumor tissue samples.10-12 It therefore seems that evaluating the extent of tumor resection by MRI will be more viable in prospective studies than in retrospective studies based on follow-up data sets spanning 15 to 20 years.