FDG and PSMA PET in metastatic castration-resistant prostate cancer (mCRPC).
Bibliographic record
Abstract
23 Background: We hypothesized 18F-DCFPyL (PSMA-based tracer) and/ or 18F-FDG (glucose metabolism-based tracer) PET/CT might provide different/complementary molecular imaging information in men with mCRPC treated with abiraterone (A) or enzalutamide (E). Methods: In this prospective cohort study (MISTER trial) mCRPC patients (pts) had conventional imaging and both PSMA and FDG PET/CT prior to standard treatment with A or E, repeated after ~10 weeks on treatment. The main objective was to compare changes in PET/CT findings with conventional imaging. Median of PET maximum standardized uptake value (SUVmax) was measured across all PET avid disease sites and change in SUVmax was evaluated in the 5 hottest sites per patient. Review of PET/CT was performed by 3 experts based on consensus. Results: 36 men were enrolled between 2/2017-12/2018, of whom 28 had treatment and followup imaging. To date, 13 cases have been reviewed: mean age 71.2 years, 7 (53.9%) were ECOG=0, median duration since diagnosis of initial cancer 7.5 months and 8 (61.5%) were stage II/III. PSMA detected more skeletal metastases, positive nodes and non-skeletal, non-nodal metastases in 5/5/3 (39%/39%/23%) men, while FDG detected more non-skeletal, non-nodal metastases in 1 man. Following treatment, new lesions were seen in 3 men on both PSMA and FDG, 3 with PSMA only, and 1 with FDG only. 12 men had baseline FDG-avid disease with median SUVmax 6.5 pre-treatment and 3.8 following therapy (all men had lower SUVmax post-treatment). All 13 men had PSMA-avid disease with median SUVmax 17.6 at baseline and 18.7 post-therapy. Following treatment, 8/12 men (67%) had SUV declines ≥30% (2 had new lesions), 4 had declines of 0-30% (2 had new lesions) using FDG; at followup, 1/13 men had PSMA SUVmax declines ≥30% or more, 6 had declines of 0-30% (2 had new lesions), 5 had SUV increases of 0-30% (4 had new lesions) and 1 had >30% increase. Conclusions: In early analyses, PSMA identified more disease burden in mCRPC pts and was more avid than FDG. SUVmax for FDG declined following treatment in all men, while PSMA changes were heterogeneous. Potential prognostic value of early PSMA and FDG imaging changes on clinical outcomes will be correlated with conventional imaging along with review of remaining cases. Clinical trial information: NCT02813226.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 | 0.000 |
| 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".