P12.47.B MOLECULAR PROFILING OF GLIOMAS: INSIGHTS INTO RADIONECROSIS AND PSEUDOPROGRESSION THROUGH NEXT-GENERATION SEQUENCING
Bibliographic record
Abstract
Abstract BACKGROUND High-grade gliomas are the most common and aggressive primary tumors of the central nervous system (CNS), posing significant diagnostic and therapeutic challenges due to their molecular heterogeneity. Next-generation sequencing (NGS) has improved diagnostic accuracy by identifying actionable genetic alterations. However, post-treatment effects such as radionecrosis and pseudoprogression may complicate disease monitoring by mimicking tumor recurrence. This study aimed to evaluate associations between specific genetic alterations identified by NGS and the development of treatment-related effects. MATERIAL AND METHODS This retrospective study included 192 patients with high-grade gliomas treated with radiotherapy between 2018 and 2023 at a Brazilian cancer center. NGS results were available for 20 patients with radionecrosis and 20 patients of a control group. Patients were grouped based on the presence or absence of post-treatment effects, radionecrosis or pseudoprogression and the groups were matched by irradiation volume. Genetic alterations and clinical outcomes were extracted from electronic medical records. Fisher’s exact test and nominal regression models were used to identify associations between molecular alterations and post-treatment effects. Statistical significance was defined as p<0.05. RESULTS Among 192 patients, 46 (23.9%) experienced post-treatment effects. Of the 20 patients with NGS data, 15 developed radionecrosis, 8 pseudoprogression, and 3 both. Although no statistically significant associations were found using Fisher’s test, TERT promoter mutations (c.1-124C>T) and EGFR amplification were the most frequent alterations in radionecrosis (n=9 and n=8, respectively). In pseudoprogression, TERT mutations (n=6), EGFR amplification (n=4), PTEN (n=4), and NF1 mutations (n=2) were identified. Nominal regression revealed significant associations between radionecrosis and EGFR amplification (p=0.004), MDM4 amplification (p=0.019), PTEN mutation (p=0.034), and SEC16A: : NOTCH1 fusion (p=0.019). Temporal analysis showed that pseudoprogression occurred earlier (median onset: 147 days), whereas radionecrosis was more delayed (200-500 days post-RT). CONCLUSION NGS provides valuable insights into the molecular landscape of high-grade gliomas and may help identify patients at risk for treatment-related effects. Understanding the genomic profile associated with radionecrosis and pseudoprogression can inform follow-up strategies and minimize misdiagnosis. These preliminary findings warrant validation in larger prospective cohorts to better elucidate the clinical relevance of these molecular alterations.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.008 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".