Summary of Recommendations

Document Overview

Design and created by Guideline Central in participation with the Congress of Neurological Surgeons.

Treatment of Adults With WHO Grade II Diffuse Glioma

Congress of Neurological Surgeons

Publication Date: Apr 15, 2026

Page Last Updated: Jul 2, 2026

Classification of Evidence

Class of evidence	Definition
Class I	Evidence from one or more well-designed, randomized controlled clinical trial, including overviews of such trials.
Class II	Evidence from one or more well-designed comparative clinical studies, such as non-randomized cohort studies, case-control studies, and other comparable studies, including less well-designed randomized controlled trials.
Class III	Evidence from case series, comparative studies with historical controls, case reports, and expert opinion, as well as significantly flawed randomized controlled trials.

Full Text Guideline: journals.lww.com/neurosurgery/fulltext/2026/05000/congress_of_neurological_surgeons_systematic.3.aspx

Source Citation: Ormond, D Ryan et al. “Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for the Treatment of Adults With WHO Grade II Diffuse Glioma: Update.” Neurosurgery vol. 98,5 (2026): 984-991. doi:10.1227/neu.0000000000003912

Document Objectives: The management of World Health Organization (WHO) grade II diffuse glioma is an important facet of all physicians involved in neuro-oncology. This is an update of the evidence-based guidelines for management of WHO grade II diffuse gliomas published by the Congress of Neurological Surgeons and American Association of Neurological Surgeons in 2015. This series of guideline documents provides an update of the information and recommendations provided in the 2015 version. It sets a benchmark as to the published information we have to support the management of this difficult disease. It also provides clues to key investigations that are necessary to move us toward effective control of WHO grade II diffuse gliomas.

Health Care Settings: Ambulatory, Hospital, Medical Transportation, Outpatient, Radiology Services