Development and validation of contouring guidelines for post-cystectomy adjuvant radiation of bladder cancer.
Bibliographic record
Abstract
409 Background: Several organizations are developing clinical trials to evaluate adjuvant radiotherapy (RT) for bladder cancer patients at elevated risk of locoregional failure (LF). However, the clinical target volumes (CTVs) & organs at risk (OARs) for this treatment have not been defined in detail. Our purpose was to define multi-institutional consensus CTVs & OARs for male & female bladder cancer patients undergoing adjuvant RT in clinical trials. Methods: We convened a multi-disciplinary group of bladder cancer specialists from 9 centers in 3 countries. 5 radiation oncologists (ROs) & 7 urologists participated in the development of the proposed contours. The group proposed initial language for the CTVs & OARs and contoured them on CT scans of a male & female cystectomy patient with input from ≥ 1 urologist at each center. Using the binomial maximum-likelihood estimates method, we generated 95% level initial contours. We evaluated the contours for level of agreement using the Landis & Koch interpretation of the K statistic. Based on the initial contouring, the group updated its descriptions of the CTVs & OARs. To determine if the revised language produced consistent contours, the cystectomy bed (CB) contour was redrawn on the CT sets by an additional 5 ROs. Results: The group proposed that patients at elevated risk for LF with R0 resections should be treated to the pelvic nodes alone (internal/external iliac, distal common iliac & presacral) whereas patients with ≥ R1 resections should be treated to the pelvic nodes & CB. The group proposed the rectum, bowel space, bone marrow & urinary diversion as OARs. The level of agreement for the initial CTVs & OARs from the group varied substantially (Table). Consensus language to describe CTV & OAR structures where the initial contours varied was successfully developed. Contours & feedback from the validation group are being analyzed. Conclusions: Initial descriptions of CTVs & OARs have been successfully developed. External validation & feedback are pending. The results will be applicable to clinical trials of adjuvant RT in bladder cancer. [Table: see text]
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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 | 0.106 | 0.181 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.007 | 0.003 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.005 | 0.004 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.002 | 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".