Predictive parameters of symptomatic haematochezia following 5-fraction gantry-based SABR in prostate cancer.
Bibliographic record
Abstract
79 Background: To identify clinical and dosimetric predictors of high-grade haematochezia (HH) following 5-fraction gantry based stereotactic ablative radiotherapy (SABR). Methods: Data about haematochezia in 258 patients who received 35-40Gy SABR in 5-fractions (weekly or alternate days) as part of sequential phase II prospective trials was retrieved. Haematochezia was graded as per the Fox Chase LENT criteria, ≥ grade 2 rectal bleeding was labeled as HH. Patients needing steroid suppositories, 4% formalin or 1-2 sessions of argon plasma coagulation (APC) were graded as grade 2 haematochezia. If a patient required >2 sessions of APC, blood transfusion or a course of hyperbaric oxygen, this was grade 3 and development of visceral fistula was grade 4. Various dosimetric and clinical factors were analyzed using univariate and multivariate (MVA) analyses. Receiver-operating characteristic (ROC) curve analysis and recursive partitioning analysis (RPA) were used to determine clinically valid cut-off points and risk groups, respectively. Results: Median follow-up was 29.7 months (IQR 20.6, 61.7). HH was observed in 19.4%. Median time to develop HH was 11.7 months (IQR 9.0, 15.2). Resolution occurred a median of 6.7 months (IQR 5.7, 12.4) later; 3% was prevalent at last follow-up. At two years, cumulative HH was 4.9%, 27.2% and 42.1% in patients who received 35Gy to prostate (4mm planning target volume-PTV margin), 40Gy to prostate (5mm PTV margin) and 40Gy to prostate/seminal vesicles (5mm PTV margin), respectively ( p-value< 0.0001). In the ROC analysis, volume of rectum receiving radiation dose of 38Gy (V38) was a strong predictor of HH with an AUC of 0.65. In MVA, rectal V38 (≥2.0cc; p-value<0.0001, OR 4.9); use of anti-coagulants (p-value<0.0002, OR 14.9) and presence of hemorrhoids (p-value<0.006, OR 3.2) were the strongest predictors. In RPA, rectal V38<2.0cc and use of anticoagulants orrectal V38 ≥2.0cc plus one other risk factor resulted in a HH risk>30%. Conclusions: Rectal V38 and two clinical factors were strong predictors of high-grade haematochezia following 5-fraction SABR. Planning constraints should aim to keep the rectal V38 below 2.0cc.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".