Abstract
We evaluated prognostic factors of adult low-grade glioma (LGG) according to the new 2016 WHO classification. Records of 153 patients diagnosed with WHO grade II LGG between 2003 and 2015 were retrospectively reviewed. Based on the 2016 WHO classification, 80 patients (52.3%) had diffuse astrocytoma, IDH-mutant; 45 (29.4%) had oligodendroglioma, IDH-mutant and 1p/19q-codeleted (ODG); and 28 (18.3%) had diffuse astrocytoma, IDH-wildtype. Gross total resection (GTR) was performed in 71 patients (46.4%), subtotal resection in 31 (20.3%), partial resection in 43 (28.1%), and biopsy in 8 (5.2%). One hundred two patients (66.7%) received postoperative radiotherapy. The 5- and 10-year progression-free survival (PFS) rates were 72.7% and 51.5%, respectively, and the 5- and 10-year overall survival (OS) rates were 82.5% and 63.5%, respectively. GTR and IDH-mutant and/or 1p/19q codeletion were favorable prognostic factors for PFS and OS. Patients with IDH-wildtype had significantly decreased OS. Among patients with ODG who underwent GTR, no recurrence was observed after radiotherapy. Patients who underwent non-GTR frequently experienced recurrence after radiotherapy (IDH-mutant: 47.6%, IDH-wildtype: 57.9%). In conclusion, molecular classification of LGG was of prognostic relevance, with IDH-wildtype patients having a particularly poor outcome, regardless of the treatment. Favorable results were observed in patients who underwent GTR.
Highlights
World Health Organization (WHO) grade II low-grade glioma (LGG) included astrocytoma, oligodendroglioma, and oligoastrocytoma[1]
The initial pathologic diagnosis was astrocytoma in 56 patients, oligodendroglioma in 44 patients, and oligoastrocytoma in 53 patients
Gross total resection (GTR) was performed in 71 patients (46.4%), subtotal resection (STR) in 31 (20.3%), partial resection (PR) in 43 (28.1%), and biopsy in 8 (5.2%)
Summary
World Health Organization (WHO) grade II low-grade glioma (LGG) included astrocytoma, oligodendroglioma, and oligoastrocytoma[1]. With increasing evidence that molecular markers, such as isocitrate dehydrogenase (IDH) 1/2 gene mutation and chromosome 1p/19q codeletion, are more important than histologic subtype in the prediction of tumor response to treatment and prognosis, phenotypic and genotypic parameters have been integrated in the updated 2016 WHO classification of gliomas[3,4,5,6]. As most previous studies about prognostic factors in LGG were based on the old histologic classification, the impact of prognostic factors in the different molecular subtypes remains to be determined. Maximal safe resection followed by adjuvant radiotherapy (RT) and PCV (procarbazine, lomustine, and vincristine) or temozolomide for high-risk patients (≤40 year old or subtotal resection)[7] is the current standard of care, optimal treatment for each molecular subtype of LGG remains disputed. We examine the impact of surgery and adjuvant RT on outcomes in molecularly defined LGG. Level
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
