A randomized trial of a shorter radiation fractionation schedule for the treatment of localized prostate cancer.
Bibliographic record
Abstract
5003 Background: Men with localized prostate cancer (PC) are often treated with high dose radiotherapy (RT) over 8-9 weeks. The α-β ratio which describes the dose-response of tumors and normal tissues to fractionated RT is low for PC. Hence, hypofractionation RT may be more efficacious in PC. Objective:To determine whether an 8-week course of escalated dose conformal RT can be compressed safely, and with similar efficacy into a 4-week course in intermediate risk PC. Methods: Men with intermediate risk PC (T1-2 Gleason 6 and PSA 10-20 ng/ml or T2b-c Gleason 6 and PSA < 20 ng/ml or T1-2 Gleason 7 and PSA < 20 ng/ml) were randomized to conventional (CON) RT, 78Gy in 39 fractions over 8 weeks or hypofractionated (HYP) RT, 60Gy in 20 fractions over 4 weeks, without hormone therapy. RT was planned to respect predefined dose constraints to a risk-adapted volume that included prostate +/- base of seminal vesicles. Daily image guidance was mandated and RT plans underwent real-time central review. The primary outcome is biochemical-clinical failure (BCF) defined by any of: PSA failure (nadir+2), hormonal intervention, clinical local or distant failure, or death. The trial was designed to show that the 5-year BCF of the HYP RT regimen is no higher than CON RT by up to 7.5% (hazard ratio [HR] up to 1.32) with 85% power and one-sided α = 5%. Acute and late GU/GI toxicity were assessed using RTOG criteria. Results:Between 2006 and 2011, 1,206 men from 27 sites in Canada, Australia and France were allocated to HYP RT (608) or CON RT (598). Mean age was 71 (48-88) years. Baseline characteristics were similar between arms. Median follow-up is 6.0 years. To date, 164 patients receiving HYP RT experienced a BCF event compared to 173 in the CON RT group. The BCF event rate at 5 years in both arms was 21%. The observed HR is 0.96 with 90% CI, 0.80 to 1.15. Overall 75 patients have died in each group. GU/GI toxicity grade > 3 was comparable in the acute period; however, late toxicity favored the HYPO RT arm: 3.5% vs. 5.4%, diff = -1.9%, 95% CI, - 4.3 to 0.43%. Conclusion: The HYP RT regimenwas not inferior to conventional RT with no increase in acute or late toxicity. Thus, it is a consideration for men with intermediate risk PC. Clinical trial information: NCT00304759.
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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 | 0.003 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| 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".