Association of time to adjuvant chemotherapy (TTAC) and overall survival among patients with rectal cancer treated with preoperative radiation.
Bibliographic record
Abstract
461 Background: Studies suggest that delayed adjuvant chemotherapy (AC) beyond 8 weeks is associated with inferior survival in early-stage colon cancer (CA). The optimal TTAC in rectal CA remains unclear. The objective of this study was to determine the prognostic effect of TTAC in stage II and III rectal CA treated with standard preoperative (op) chemoradiation. Methods: Patients with stage II/III rectal CA treated with pre-op chemoradiation, received post-op AC, and referred to the British Columbia Cancer Agency between 1999 and 2008 were included. Univariate and multivariate analyses were conducted using Kaplan Meier and Cox regression methods to evaluate the association between TTAC and outcomes. X-tiles cut-point analysis was performed to determine the optimal TTAC. Results: A total of 327 eligible patients were identified: median age 61 (range 22-85), 70% male, and 75% stage III. In terms post-op AC, 51% received 5-fluorouracil (5-FU), 32% received capecitabine, 12% received 5-FU and oxaliplatin, and 5% received other chemotherapy. Median TTAC was 7.0 weeks (wks) (range 1.6-33.3 wks). Cut-point analysis revealed the optimal TTAC to be 5.6 wks (HR: 0.42, 95%CI 0.22-0.82, p=0.0087). Initiation of AC within optimal TTAC (5.6 wks) and 6 wks from date of surgery (sx) was associated with a significant survival benefit while no significant effect was seen at 8 wks. TTAC of ≤ 6 wkswas found to be a significant prognostic factor in multivariate analysis (p=0.047) adjusted for ECOG, age, sex, stage, margin status, and grade. In stratified analysis by stage, patients with stage III disease benefited from AC (p=0.018) while those with stage II did not (p=0.71). Conclusions: In this study, the optimal TTAC was 6 weeks or less. Initiation of AC within this time frame was associated with improved OS. This is less than the optimal timeframe indicated in the literature for colon CA. [Table: see text]
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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 | 0.000 | 0.002 |
| 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) | 0.001 | 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".