Real-World Evaluation of Primary Versus Secondary Prevention of Skeletal-Related Events in Metastatic Castration-Resistant Prostate Cancer
Bibliographic record
Abstract
INTRODUCTION: Anti-osteoclast treatment with denosumab or zoledronate is known to effectively reduce the need for radiotherapy to bone and other skeletal-related events (SREs) in patients with metastatic castration-resistant prostate cancer (mCRPC). In this study, we analyze primary versus secondary initiation of bone-targeting agents (BTAs) relative to first palliative bone radiotherapy in patients dying of mCRPC. METHODS: Provincial administrative databases from Ontario, Canada identified patients with prostate cancer (2007-2018, n = 98 646) who received continuous androgen deprivation therapy (n = 29 453), died of prostate cancer (2013-2018, n = 3864), and received life-prolonging therapy for mCRPC (n = 1850). Variables were collected looking back 3 years from death. Multivariable analysis explored the relationship between clinical variables and BTAs. RESULTS: Of the 58% (1066/1850) patients with mCRPC who received BTA, only 289 (25.4%) started BTA prior to first palliative bone radiotherapy as primary prevention. Eight hundred and forty-eight (74.6%) patients either never received BTA before death (n = 447) or started BTA only after first bone radiotherapy (n = 401). More patients received denosumab (n = 825, 77%) than zoledronic acid (n = 241, 23%). 51.2% (582/1137) of palliative bone radiotherapy was initiated in the last 12 months of life. Factors associated with the use of BTA included elevated alkaline phosphatase (OR = 1.0, P = .023), de novo metastases (OR = 1.4, P = .005), medical oncologist involvement (OR = 2.0, P = .007), diagnosis 2012-2017 versus 2007-2011 (OR = 0.75, P = .034), and academic center (OR = 0.061, P = .007). CONCLUSION: A majority of patients with mCRPC never receive BTAs prior to first SRE, despite universal access and availability of these agents in Ontario. These results highlight an opportunity to improve outcomes by emphasizing early introduction of BTA in patients with mCRPC being started on systemic therapy.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".