Oral Cyclophosphamide for Patients With Metastatic Castration-Resistant Prostate Cancer in a Scenario of Limited Health Care Resources
Bibliographic record
Abstract
PURPOSE: Prior noncontemporary studies showed that oral cyclophosphamide is an active treatment of metastatic castration-resistant prostate cancer (mCRPC). However, cyclophosphamide is currently underutilized in routine clinical practice given the lack of survival benefit and the emergence of more effective treatments. METHODS: We retrospectively reviewed our institutional database to identify patients with mCRPC treated with cyclophosphamide. Prostate-specific antigen decrease ≥50% from baseline (PSA50) response was determined as the proportion of patients achieving a prostate-specific antigen (PSA) decline ≥50% from baseline. Radiographic responses and progression were evaluated by Prostate Cancer Working Group 3. Survival estimates used the Kaplan-Meier method, and correlations were made with Chi-square test for categorical variables. RESULTS: From January 2011 to January 2023, 341 patients with mCRPC received oral cyclophosphamide at a tertiary cancer center in São Paulo, Brazil. The most common regimen (95%) was 100 mg once daily 21 days on, 7 days off. At prostate cancer diagnosis, the median age was 64.4 years (IQR, 59.4-70.8), 61.9% had metastatic de novo disease, and 55.5% had Gleason ≥8. The median number of previous treatment lines was three (IQR, 2-4). Any PSA decline was observed in 33.4%, and 13.2% had a PSA50 response. Median response duration was 2.1 months (IQR, 1.4-3.8). Ten patients (3%) were treated for ≥1 year. PSA50 response was associated with no prior docetaxel use and Eastern Cooperative Oncology Group performance status 0 or 1. CONCLUSION: Oral cyclophosphamide is a feasible treatment option for patients with mCRPC, particularly in a scenario of limited health care resources.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".