ProSpare’s tolerability is independent of rectal anatomy
Bibliographic record
Abstract
ProSpare, a self-insertable rectal obturator, has shown promise in reducing prostate motion and anorectal dosimetry in prostate radiotherapy.However, initial data from a post-prostatectomy radiotherapy trial (POPS trial NCT02978014) revealed that 37% of patients could not tolerate ProSpare insertion, possibly because of a mismatch with rectal anatomy.Our study aimed to compare rectal anatomy between patients who could and could not tolerate ProSpare insertion and determine threshold values for anorectal angle, anal canal length, or rectum diameter conducive to insertion.We analysed the anorectal angle, anal canal length, and rectal diameter in patients who could tolerate ProSpare insertion (Group Y), those who could not (Group N), and those with ProSpare inserted (Group PS), by using planning CT scans from the POPS trial.There were no significant differences in the anorectal angle, anal canal length, or rectal diameter between Group Y and N (p>0.05).There were significant differences between Group PS and the others in anorectal angle (p<0.01) and rectal diameter (p<0.001).These results suggest rectal anatomy is unlikely the limiting factor for ProSpare tolerance; instead, it could be anal sphincter diameter or tone, or nociceptive sensitivity.Patients with ProSpare showed increased anorectal angles and rectal diameters, suggesting the rectum expands to accommodate the device.This supports ProSpare's efficacy as a rectal spacer during prostate radiotherapy.We recommend the future development of rectal obturators should follow the design of deployable or inflatable devices while emulating ProSpare's properties.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| 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 | 0.001 |
| 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".