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Clinical impact of [18F]FET-PET/CT in differentiating treatment-associated changes and tumor progression in
Veerle J Ruijters1, Anass El Ghalbouni1, Arthur J A T Braat2
1Department of Neurology, UMC Utrecht, UMC Utrecht Brain Center, Utrecht, The Netherlands.
Background:
MRI follow-up of diffuse glioma patients often results in diagnostic uncertainty between treatment-associated changes (TAC) and true progressive disease (PD). While [18F]FET-PET improves diagnostic accuracy, research on clinical impact and optimal clinical timing is scarce. This study evaluates the clinical impact of adding [18F]FET-PET to MRI in cases of uncertainty and effect of timing between immediate [18F] FET-PET use (≤6 weeks after first MRI with new or increasing enhancement) versus delayed use (>6 weeks).
Methods:
This single-center retrospective cohort study included adult glioma patients (grade 2-4) who underwent [18F]FET-PET due to uncertainty regarding PD versus TAC on MRI. Primary outcome was a clinical policy change based on [18F]FET-PET results. Secondary outcomes included policy change validity, unnecessary interventions (ie diagnostic or therapeutic interventions that could have been prevented with early correct diagnosis), and diagnostic accuracy (based on pathology or radiological follow-up). All outcomes, except diagnostic accuracy, were compared between immediate and delayed [18F]FET-PET groups.
Results:
Of 41 included patients, 78% had glioblastoma and 54% received chemoradiation. Policy changes occurred in 22 cases (54%), of which 18 (82%) were supported by clinicoradiological follow-up or pathology. No significant difference in policy changes was found between immediate and delayed [18F]FET-PET groups. Unnecessary interventions, including chemotherapy and MRI scans, occurred only in the delayed group.
Conclusion:
In this retrospective analysis, [18F]FET-PET influences clinical decision-making in over half of cases, and performing [18F]FET-PET at the earliest possible time likely prevents unnecessary interventions. Larger prospective studies are needed to confirm its clinical value and optimal timing.
Insights
[18F]FET-PET imaging aids diffuse glioma diagnosis, distinguishing treatment effects from progression. Early use of [18F]FET-PET scans after MRI can prevent unnecessary interventions in glioma patients.
Area of Science:
- Neuro-oncology
- Radiology
- Nuclear Medicine
Background:
- Distinguishing treatment-associated changes (TAC) from true progressive disease (PD) in diffuse glioma patients is challenging with MRI follow-up.
- While [18F]FET-PET enhances diagnostic accuracy, its clinical impact and optimal timing remain under-researched.
- This study investigates the clinical utility of adding [18F]FET-PET to MRI and compares immediate vs. delayed imaging protocols.
Purpose of the Study:
- To evaluate the clinical impact of [18F]FET-PET in MRI-uncertain diffuse glioma cases.
- To assess the effect of immediate (≤6 weeks) versus delayed (>6 weeks) [18F]FET-PET imaging timing.
- To analyze policy changes, unnecessary interventions, and diagnostic accuracy.
Main Methods:
- Retrospective cohort study of adult glioma patients (grade 2-4) with diagnostic uncertainty on MRI.
- [18F]FET-PET was used to differentiate progressive disease from treatment-associated changes.
- Clinical policy changes, validity, unnecessary interventions, and diagnostic accuracy were primary and secondary outcomes.
Main Results:
- A clinical policy change occurred in 54% of cases, largely supported by follow-up data.
- No significant difference in policy changes was observed between immediate and delayed [18F]FET-PET groups.
- Unnecessary interventions, including chemotherapy and MRI scans, were exclusively observed in the delayed imaging group.
Conclusions:
- [18F]FET-PET significantly influences clinical decision-making in over half of diffuse glioma patients with diagnostic uncertainty.
- Early [18F]FET-PET imaging appears crucial for preventing unnecessary interventions.
- Further prospective studies are warranted to confirm clinical value and optimal timing.
