Clinical effectiveness of adjuvant chemotherapy (AC) with or without oxaliplatin following neoadjuvant chemoradiotherapy (nCRT) in stage II rectal cancer (RC).
Bibliographic record
Abstract
686 Background: Use of AC in RC following nCRT is controversial because of concerns regarding its potentially small magnitude of benefit. We aimed to 1) examine real-world patterns of AC use in stage II RC and assess its impact on outcomes and 2) determine whether the addition of oxaliplatin to fluoropyrimidines modifies effectiveness. Methods: Using a cohort of yp stage II RC patients from 5 Canadian centers that underwent curative surgery, we assessed the relationship between AC +/- oxaliplatin and overall (OS) and disease free survival (DFS). Cox models adjusting for age, gender, ECOG, and high risk features (T4 lesion, poor differentiation, inadequate lymph node sampling, lymphovascular/perineural invasion, and obstruction/perforation) were constructed. Results: Among 485 pts, 74% received AC of whom 19% received oxaliplatin-based treatment. Median follow up was 4.5 yrs. Pts in the AC group were younger (median age 61 vs 64; P= 0.003) and had higher rates of TME (82% vs 79%; P= 0.049), but they had similar demographics, ECOG, high risk features, preoperative CEA, margin status and nCRT regimen when compared to pts in the non-AC group (all P> 0.05). Multivariate analyses demonstrated that receipt of any AC (OS HR 0.93 95% CI 0.58-1.50 P =0.77; DFS HR 0.91 95% CI 0.58-1.43 P =0.69), fluoropyrimidine AC (OS HR 0.82 95% CI 0.49-1.36 P =0.44; DFS HR 0.83 95% CI 0.51-1.34 P =0.44), or oxaliplatin-based AC (OS HR 1.37 95% CI 0.74-2.55 P =0.32; DFS HR 1.17 95% CI 0.66-2.05 P =0.59) did not improve outcomes versus no AC. In subgroup analyses that stratified pts by high risk features, presence of 1, 2, or 3 high risk factors, preoperative CEA and margin status, AC did not result in better OS or DFS in any subgroup. A further exploratory analysis that focused only on those receiving AC within 12 weeks of surgery did not reveal any consistent correlations between AC and survival. Conclusions: Use of fluoropyrimidine or oxaliplatin-based AC in this multi-institutional cohort of yp stage II RC pts after nCRT did not improve outcomes compared to observation. Conventional high risk features used to risk stratify stage II colon cancer for AC decision making have limited utility in RC after nCRT.
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How this classification was reachedexpand
Direct model labels (unvalidated)
Per-model category and study-design labels from the labeling rounds. They are machine output, unvalidated, and the disagreement between models ships as data. No study design here is MEDLINE-validated yet.
| Model arm | Categories | Study design | Confidence |
|---|---|---|---|
| gemma | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: no | Observational | high |
| gpt | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: no | Observational | high |
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 | 0.001 | 0.003 |
| 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, unvalidatedLabeled directly by 2 models reading the full record.
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".