Development of a predictive model of PSA response to a switch from prednisone to dexamethasone in metastatic castrate-resistant prostate cancer patients biochemically progressing on abiraterone.
Bibliographic record
Abstract
88 Background: Abiraterone acetate (AA) is typically administered with prednisone (P) to prevent symptoms of mineralocorticoid excess in patients with metastatic castrate resistant prostate cancer (mCRPC). After biochemical progression on AA + P, there is a sizeable subset of patients who have a renewed PSA response when switched from P to dexamethasone (D). The purpose of this study was to delineate clinical and pathologic factors that are predictive of a PSA response to such a steroid switch. Methods: We performed a retrospective analysis of 87 patients switched from AA+P to AA+D at Sunnybrook Odette Cancer Centre (Toronto, ON, Canada) between December 2012 and September 2018. Information on demographics, disease characteristics, previous treatments and performance status was collected. Response to the P to D switch maneuver was defined as a decrease in PSA by ≥30% within 12 weeks of the intervention (PSA30). Univariate logistic regression analyses were used to create a prediction model for each covariate tested, and R2 was applied for the measure of fit.Using multivariable logistic regression analysis and a backward stepwise selection procedure, we sought to identify patient and/or disease characteristics associated with a PSA30. Results: 38/87 patients (44%) experienced a PSA30. Univariate analysis showed that a favourable ECOG performance status, no prior docetaxel and no prior enzalutamide use were associated with a PSA30. On multivariable logistic regression analysis both favourable ECOG performance status and no prior enzalutamide use remained associated with a PSA30 (Table). Conclusions: A considerable proportionof patients with mCRPC who biochemically progress on AA+P have a renewed PSA response when changed to AA+D.Patients with a favourable ECOG performance status and no prior enzalutamide use are more likely to respond to such a steroid switch. Further prospective studies are needed to validate our findings.[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 | 0.004 | 0.008 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.002 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".