Predictors of radiotherapy-related gastrointestinal toxicity from anal cancer DP-IMRT: Secondary analysis of RTOG 0529.
Bibliographic record
Abstract
460 Background: Radiation Therapy Oncology Group (RTOG) 0529 assessed feasibility of dose-painted intensity-modulated radiation therapy (DP-IMRT) to reduce the acute morbidity of chemoradiation with 5-fluorouracil (5FU) and mitomycin-C (MMC) for T2-4N0-3M0 anal cancer. This secondary analysis was performed to identify patient (pt) and treatment factors associated with acute and late gastrointestinal (GI) adverse events (AEs). Methods: RTOG 0529 treatment plans were reviewed to extract dose-volume data for tightly contoured small bowel (SB), loosely contoured anterior pelvic contents (APC), and uninvolved portions of colon outside the clinical target volume (UC). T-tests were performed to evaluate differences in the mean absolute volumes of each critical structure receiving doses ≥ 5 to 60 Gy (V5-V60) in 5 Gy increments between pts with and without ≥ grade (G) 2, acute and late GI AEs, and ≥G3 acute GI AEs using the NCI Common Terminology Criteria, version 3. Acute is defined as ≤ 90 days from the start of treatment and late is > 90 days. Additional factors (age, location, gender, race, Zubrod, grade, size, stage, prone vs supine position) were also evaluated in multivariate (MV) logistic regression (acute AEs) or Cox proportional hazards models (late AEs) to evaluate correlation with GI AEs. Results: Among 52 evaluable pts, ≥G2 acute, ≥G2 late, and ≥G3 acute GI AEs were observed in 35, 17, and 10 pts, respectively. Trends (p<0.05) towards statistically significant associations were observed between: ≥G2 acute GI AEs and SB dose (V20-V40); ≥G2 late GI AEs and APC dose (V60); ≥G3 acute GI AEs and APC dose (V5-V25), increasing age, tumor size >4cm, and worse Zubrod. SB and APC dose parameters remained correlated with GI AEs on MV analysis. Treatment in the prone vs supine position correlated with lower SB V10-V35 and APC V5-V20, although no significant differences in GI AEs were observed. Conclusions: Acute and late GI AEs from 5FU/MMC chemoradiation using DP-IMRT correlates with RT dose to the SB and APC. Further analysis is underway to determine critical structure cut-point parameters that may aid treatment plan optimization for anal cancer DP-IMRT. Supported by RTOG U10 CA21661, CCOP U10 CA3742 and ATC U24 CA 81647 NCI grants. Clinical trial information: NCT00423293.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.003 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 teacher head, 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".