Assessing efficacy and toxicity in rectal cancer radiotherapy: a comparative study of two fractionation regimens
Bibliographic record
Abstract
Abstract Objectives Rectal cancer is a significant global health concern, with radiotherapy playing a crucial role in treatment. However, optimal fractionation regimens remain debated, particularly with newer treatment techniques such as the use of Halcyon-based radiotherapy. This study aims to compare dosimetric and radiobiological parameters between two radiotherapy regimes for rectal cancer: 50 Gy/25 fractions and 50.4 Gy/28 fractions. Methods A retrospective analysis of 28 treatment plans was conducted. Group A (10 plans) received 50 Gy/25 fractions, while Group B (18 plans) received 50.4 Gy/28 fractions. The study evaluated parameters including dose volume histograms (DVH), conformity index (CI), homogeneity index (HI), tumor control probability (TCP), normal tissue complication probability (NTCP), equivalent uniform dose (EUD), and biologically effective dose (BED) across the two groups. Results No significant dose differences were found in normal tissues between the groups. However, it demonstrated a significantly higher conformity index (CI) for the planning target volume (0.98 ± 0.01 vs. 0.96 ± 0.02, p=0.007) and biologically effective dose (BED) (71.82 ± 0.32 vs. 70.08 ± 0.08, p<0.001). Additionally, Group A exhibited a higher normal tissue complication probability (NTCP) for the bladder (0.03 ± # vs. 0.02 ± #, p=0.004). Conversely, Group B had a lower tumor control probability (TCP) compared to Group A. Conclusions Group A offers better tumor coverage and comparable TCP but has a higher NTCP, indicating a potential increase in normal tissue complications compared to Group B. While the study provides valuable dosimetric and radiobiological insights, its retrospective nature and limited sample size pose constraints on generalizability.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".