Pilot study of focal salvage high-dose rate (HDR) prostate brachytherapy in patients with local recurrence after definitive external-beam radiotherapy (XRT).
Bibliographic record
Abstract
264 Background: Studies of post-treatment biopsies of the prostate after definitive dose-escalated XRT for intermediate-risk prostate cancer suggest that approximately 20% will be positive. Salvage options include surgery, brachytherapy, cryotherapy or high-frequency ultrasound. However, the complication risk, such as fistula, incontinence or bladder neck contracture, is not insignificant. The objective of this pilot study is to explore the toxicities and efficacy of focal salvage HDR prostate brachytherapy. Methods: This study was approved by the institution’s research ethics board. Eligible patients included those with biopsy-confirmed local recurrence >30 months after completing XRT, MRI of the prostate demonstrating solitary recurrence confined to the prostate, negative metastatic workup, IPSS <15, post-XRT PSA <10ng/mL, prostate volume ≤50cc. Salvage HDR brachytherapy was performed under transrectal ultrasound guidance with a prescription dose of 27Gy divided over two implants separated by 1 week to the target volume (TV) as seen on MRI with dose constraints to the urethra and rectum. Results: Six patients were enrolled in the study. The mean age was 73 years, all had either low- or intermediate-risk disease at presentation, and initial XRT received was 70-78Gy at least 5 years ago. The Gleason score of the local recurrence was 7 and 8-10 in 4 and 2 patients, respectively. The pre-HDR mean PSA was 5.5. The median size of the recurrence on MRI was 9mm and median size of the TV was 5.0cc (2.2-10.2), TV V100% 95.1%, urethral D10% 51.8% and rectal D1cc 39.2%. Four patients have at least 3 months of follow-up, and no acute GU/GI grade 3-5 toxicities were observed, including urinary retention. The most common acute toxicity was frequency and nocturia. Mean IPSS at baseline, 4-weeks, 3-months was 7, 9 and 7. Conclusions: Preliminary data suggests that focal salvage HDR brachytherapy was technically feasible with mild acute toxicities. Clinical trial information: NCT01583920.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 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) | 0.002 | 0.001 |
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".