Emerging magnetic resonance imaging (MRI) research reveals that gross total resection (GTR) of contrast-enhanced tumor (CET) and non-contrast-enhanced tumor (NET) (GTR-NET) facilitates significantly enhanced survival in patients with IDH wild-type glioblastomas, irrespective of age or O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status.
For the retrospective study, recently published in Radiology, researchers utilized a conditional inference tree (CIT) model to predict overall survival (OS) in patients with GTR-NET and the following patient groups who did not have GTR-NET: patients < 60 years of age; patients > 60 years of age and positive for MGMT; and patients > 60 years of age and negative for MGMT.
Patients with GTR-NET had the longest median OS at 32.6 months, according to the study authors.
In contrast, for patients who did have GTR-NET, the researchers noted training set data showing a median OS of 23.4 months for patients < 60 years of age, a median OS of 19.1 months for patients > 60 years of age and positive for MGMT, and a median OS of 10.7 months for patients > 60 years of age and negative for MGMT.
“Our study highlights the importance of radiologic assessment of GTR-NET in preoperative and postoperative imaging, particularly because isocitrate dehydrogenase (IDH) wild-type glioblastomas are increasingly recognized as non-contrast-enhanced infiltrative tumors under the WHO 2021 Classification of Tumors of the Central Nervous System guidelines,” wrote lead study author Hye Hyeon Moon, M.D., Ph.D., who is affiliated with the Department of Radiology and Research Institute of Radiology at the University of Ulsan College of Medicine and Asan Medical Center in Seoul, Korea, and colleagues.
In two separate external validation cohorts, the researchers found that GTR-NET offered consistently longer OS in comparison to those without GTR-NET (30.4 months vs. 16.5 months and 28.8 months vs. 15.8 months).
Three Key Takeaways
1. Gross total resection of contrast-enhanced and non-contrast enhanced tumor (GTR-NET) improves survival. Patients with IDH wild-type glioblastomas who undergo GTR-NET have significantly longer overall survival (OS), with a median OS of up to 32.6 months, regardless of age or MGMT methylation status.
2. Radiologic assessment is crucial. Accurate pre- and postoperative MRI evaluation of NETs is essential due to the infiltrative, non-contrast-enhanced nature of IDH wild-type glioblastomas as recognized in the WHO 2021 CNS tumor classification.
3. Diffusion tensor imaging enhances supramaximal resection. Utilizing diffusion tensor imaging enables safer supramaximal resection, potentially maximizing tumor removal while preserving neurological function.
Although the study findings illustrate the benefits of GTR-NET, the study authors noted that MRI emphasis on diffusion tensor imaging helps ensure optimal supramaximal resection by providing insight into navigating bordering functional cerebral areas.
“Functionally guided resection, including preoperative diffusion tensor imaging scans to estimate white matter fiber tract location and awake craniotomy with cortical and subcortical stimulation, should help surgeons in achieving supramaximal resection while preserving critical functions,” emphasized Moon and colleagues.
(Editor’s note: For related content, see “A Closer Look at MRI-Guided Adaptive Radiotherapy for Monitoring and Treating Glioblastomas,” “What MRI Research Reveals About Tumor Sphericity in Patients with IDH-Wildtype Glioblastoma” and “Can AI Help Differentiate Between Tumor Recurrence and Pseudoprogression on MRI in Patients with Glioblastoma?”)
In regard to study limitations, the authors acknowledged the possibility of more favorable performance with the survival model in light of utilizing a prospective glioma registry for the training set. The researchers also conceded qualitative assessment of the extent of resection for NETs and a lack of evaluation for posr-op adverse effects.
