Population-based assessment of surrogate endpoints (SE) in stage I-III colon (CCa) and rectal cancers (RCa).
Bibliographic record
Abstract
3538 Background: In adjuvant CCa trials, 3 year disease free survival (3Y DFS) is a validated SE of 5 year overall survival (5Y OS), but this SE is less established in RCa. Effective systemic therapies introduced since 2004 may diminish the association between 3Y DFS and 5Y OS. The objective of this study was to measure SE in CCa and RCa in a population based setting, stratifying by tumor stage and era of diagnosis. Methods: Patients diagnosed with stage I-III CCa and RCa referred to any 1 of 5 regional cancer centers in British Columbia between 1990 and 2009 were followed by the GI Outcomes Unit. Clinical, pathological, and treatment characteristics were prospectively collected. R2 resections and early relapses were excluded. Relapses were classified as loco regional (LR) or distant. DFS and OS were measured from the date of definitive surgery until relapse or death. Correlation between DFS and OS endpoints was determined using Pearson’s r coefficients. Hazard ratios (HR) were generated using multivariate Cox regression and compared between DFS and OS. 5Y OS HR was compared to calculated 5Y OS using 3Y DFS rates and the validated SE model. Results: Of 9147 referred patients with early stage CCa or RCa, 9031 were eligible, with 5357 CCa and 3674 RCa. The median age was 67, 55% were male, 17/34/49% had stage I/II/III disease, respectively, 51% received adjuvant chemotherapy and 87% of RCa received radiation. There were 2494 (28%) relapses of which 90% were distant. The correlation between HR for DFS and OS, 3Y DFS and 5Y OS, and 3Y LR DFS and 5Y OS were all very strong in the total population, for CCa and RCa, across stages and eras (Table 1). Predicted 5Y OS HR were similar to the observed HR where all estimates fell within the observed confidence intervals. Conclusions: A strong association between 3Y DFS and 5Y OS was observed in this population-based cohort, which did not differ between CCa and RCa. Correlations remained significant when stratified by tumor stage and treatment era. 3Y LR DFS was a strong surrogate of 5Y OS in RCa. Pearson's r. DFS vs OS 3Y DFS vs 5Y OS 3Y LR DFS vs 5Y OS All 0.93 0.84 0.87 CCa 0.93 0.83 0.87 RCa 0.92 0.84 0.87 Stage I 0.96 0.86 0.88 II 0.94 0.81 0.85 III 0.92 0.84 0.88 Era ≤ 2004 0.94 0.85 0.87 > 2004 0.90 0.82 0.87
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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 | 0.005 | 0.011 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".