RTRB-03SHORT DELAY IN INITIATION OF RADIOTHERAPY WITH CONCURRENT CHEMOTHERAPY FOR GLIOBLASTOMA: A SECONDARY ANALYSIS OF NRG ONCOLOGY/RTOG 0525 AND 0825
Bibliographic record
Abstract
INTRODUCTION: We previously reported the unexpected finding that survival was significantly improved in patients with newly-diagnosed GBM when radiation was initiated later (>4 weeks post-op) compared to earlier (≤2 weeks post-op). That analysis included 2855 patients from 16 RTOG trials conducted prior to the era of concurrent temozolomide (TMZ) with RT. We now report on 1127 patients from two studies involving newly-diagnosed GBM, treated with RT + TMZ followed by adjuvant TMZ. Our hypothesis was that concurrent TMZ has a synergistic/radiosensitizing mechanism, making RT timing less significant. METHODS: Data from patients on both arms of RTOG 0525 and the placebo arm of RTOG 0825 were investigated. An analysis comparable to our prior study was performed to determine whether there was still an impact on survival by delaying RT in the RT + TMZ era. Overall survival was investigated using Cox proportional hazard model. Progression from diagnosis to 30 days after RT completion was analyzed using Chi-square test. RESULTS: 94.9% of the patients started RT 2-5 weeks post-op. Given the small number of patients who started RT early, comparisons were made between >4 and ≤4 weeks delay of radiation. There was no statistically significant difference for overall survival (p-value = 0.29; HR = 0.93; 95% CI: 0.80-1.07) after adjusting for RPA and MGMT methylation status. Similarly, the rate of early progression did not differ significantly (p-value = 0.59). CONCLUSIONS: We did not see a significant prognostic influence of delaying radiation within the range of 2-5 weeks post-op when given concurrently with TMZ for newly-diagnosed GBM. TMZ may "level the playing field" for patients treated with chemoradiation and offset the effect of RT delay that was seen when RT was given alone; however, the effects of early initiation of radiation tested previously could not be replicated. Supported by National Cancer Institute grants U10CA21661, U10CA180868, U10CA180822 and U10CA37422, Merck & Co. and Genentech.
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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 | 0.004 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.004 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
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".