A prospective, multinational comparison of multi-parametric and whole body magnetic resonance imaging (mp-MRI and WB- MRI) F-18 fluoro-methyl-choline (FCH) and Ga-68 HBED-CC- (PSMA) in high risk men being considered for salvage radiation treatment for biochemical failure post radical prostatectomy: Detection rates, management impact and treatment response.
Bibliographic record
Abstract
458 Introduction: Men presenting with rising PSA following radical prostatectomy (RP) may be cured by salvage radiotherapy (SRT). However, a significant proportion of men will not benefit from SRT, more frequently in those with high risk features. Imaging options such as FCH and PSMA PET/CT, and MRI may better identify men who will best benefit. The aim of this study was to evaluate the predictive value of new methods of imaging in triaging men unlikely to benefit from SRT despite negative or equivocal conventional imaging. Methods: Prospective, multisite, international trial in men post RP with negative or equivocal conventional imaging, high risk features (PSA > 0.2ng/ml and >GSC 7 or PSA DT 1.0ng/ml) and rising PSA being considered for SRT . 91 eligible enrolled men underwent FCH PET/CT, mp-MRI and WBMRI within 2 weeks, with additional PSMA in (31/91). All imaging was double read. Treatment plan was documented before and after imaging to assess management impact, and all subsequent treatments, biopsies and serial PSA collected. Imaging results were validated using a composite reference standard. Treatment response was defined as a PSA drop of > 50% in response to SRT in the absence of ADT. Results: Median PSA at imaging 0.41±1.2, median Gleason score 8, median PSA doubling time 5.0 months. By modality, detection rates for any recurrent PCa were (24/89)27%, (29/91)32% and (13/31)43% for mp-MRI, FCH and PSMA respectively (WBMRI reported separately). In men with positive scans, extra-fossa disease was identified in (11/24) 41% (mpMRI), (17/29) 58% (FCH) and (9/13) 69% (PSMA). Comparing PSMA and FCH imaging, PSMA identified 36 sites of disease (13/30 men) compared to 20 (13/30 men) on FCH (p < 0.005). Imaging findings changed expected management in 46% (42/91) due to FCH, and 23% (21/90) MRI. PSMA provided incremental management change in 7/31 (23%) over FCH. Treatment response to SRT ((fossa +/- regional nodes) was 33/45 (72%) (negative or fossa confined) FCH vs. 3/9 (33%) with extra-fossa +ve FCH (p< 0.03), 7/8 (87%) (negative or fossa confined) PSMA vs, 1/7(14%) extra-fossa +ve PSMA (p<0.009). Conclusions: A high incidence of extra-prostatic disease was identified with FCH, PSMA and MRI in high risk men with (negative conventional imaging) rising PSA post RP being considered for salvage radiotherapy. This had a consequent high management impact and significant effect on treatment response, with the highest response in men with negative or fossa-confined disease on PET/CT.
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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 | 0.007 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| 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".