Simultaneous versus staged resection for synchronous colorectal cancer liver metastases: A population-based cohort study.
Bibliographic record
Abstract
3612 Background: Simultaneous resection of colorectal cancer primary and liver metastases is not performed routinely due to concerns about safety. We hypothesized that simultaneous resection has steadily increased overtime and that the outcomes are similar. Methods: Population-based cohort study of patients undergoing resection for synchronous (resection of the primary colorectal cancer and liver metastases within six months) liver metastases from 2006-2015 by linking administrative datasets in Ontario, Canada. Outcomes: post-operative complications, length of hospital stay, and overall survival. Survival for the staged group was measured from the last surgical resection to death and estimated using Kaplan Meier and compared with the log-rank test. Cox proportional hazard models were used to calculate risks for death. We aimed to identify practice patterns, outcomes of simultaneous vs. staged resections for these patients. Results: Of 2,738 patients undergoing colorectal and liver resection for colorectal cancer, 1,168 were synchronous, of which, 442 underwent simultaneous resection. Rate of synchronous disease presentation increased on average by 3% per year (p = 0.02). Median length of stay was shorter (8 vs. 11 days, p < 0.001); rate of major liver resections were lower (17% vs. 65%, p < 0.001), and 90-day post-operative mortality was higher (6% vs. 1%) for simultaneous resections. Major postoperative complications were higher in the simultaneous group (28% vs. 23%, p = 0.067), mostly due to a higher reoperation rate (6% vs. 3%, p = 0.034). Median overall survival was worse with simultaneous resection (40 months, 95%CI 35-46 vs. 78 months, 95%CI 59-86). Risks factors for worse survival were comorbidities, rurality, right-sided primary and simultaneous resection. There is selection bias that favours survival in the staged group, as patients must have survived the first operation and have stable disease in order to undergo the second operation. Conclusions: Simultaneous resection is associated with worse postoperative outcomes. Considering selection bias, randomized studies would be necessary to determine the role of simultaneous.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".