A recent international study found that patients with isocitrate dehydrogenase wild-type glioblastoma who underwent full removal of both contrast-enhanced and noncontrast-enhanced tumors had significantly longer overall survival.
The investigators analyzed clinical and magnetic resonance imaging (MRI) data from over 600 patients treated at hospitals in South Korea, the United States, and Thailand. Complete resection of noncontrast-enhanced tumors (NET)—areas appearing on MRI as abnormal signals without contrast uptake—was strongly associated with improved survival outcomes.
In the primary cohort of 201 patients, those who underwent gross total resection (GTR) of NET had a median overall survival (OS) of 32.6 months. In contrast, patients who had only contrast-enhanced tumor removed or had no GTR had median OS ranging from 10.7 to 23.4 months, depending on age and O6-methylguanine DNA methyltransferase (MGMT) promoter methylation status.
Using a conditional inference tree model, the investigators stratified patients into four risk groups based on GTR-NET status, age, and MGMT methylation. Patients without GTR-NET were further classified: younger patients had better survival compared with older patients, and those with methylated MGMT lived longer compared with those without methylation.
The model was validated in two external data sets—one with 352 patients and another with 60. Similar survival patterns across all groups confirmed the model’s relevance in real-world settings.
“[GTR] of [NET] was an independent prognostic factor for longer [OS], regardless of age and [MGMT] promoter methylation status, in patients with isocitrate dehydrogenase wild-type glioblastoma,” said lead study author Hye Hyeon Moon, of the Department of Radiology and Research Institute of Radiology at the University of Ulsan College of Medicine at the Asan Medical Center, and colleagues. They added that resection of NET provided prognostic value beyond traditional markers like age and MGMT status.
NET regions are often more difficult to identify and remove because they don't enhance with contrast agents on MRI, though they may still harbor active tumor cells. The investigators used advanced MRI techniques to distinguish NET from postoperative edema or surgical changes, ensuring accurate classification.
Time-dependent analyses showed the survival model had moderate predictive accuracy. Sensitivity for identifying the low-risk group ranged from 70.7% to 87.9% at 1 and 2 years across validation sets.
All patients received standard glioblastoma treatment, including radiation and temozolomide. Surgical decisions followed institutional protocols, and imaging interpretation was performed by experienced radiologists using standardized criteria.
Limitations included reliance on visual rather than volumetric assessment of NET and a lack of data on neurologic outcomes following aggressive resections. Nonetheless, the investigators emphasized the importance of NET resection as a potential factor in surgical planning when clinically appropriate.
The investigators concluded that incorporating NET resection into treatment strategies may support more personalized care among patients with this aggressive brain tumor.
The authors reported no conflicts of interest.
Source: Radiology