Simultaneous versus staged resection for synchronous colorectal liver metastases: A population-based cohort study
Bibliographic record
Abstract
BACKGROUND: Synchronous liver metastases from colorectal cancer may be resected simultaneously with the primary or as a second staged operation. We evaluated trends of resection for synchronous colorectal cancer liver metastases and associated patient outcomes. METHODS: This is a retrospective cohort study that included patients undergoing resection for synchronous colorectal cancer liver metastases from 2006 to 2015 in the province of Ontario, Canada (population 13 million). Simultaneous resections occurred on the same admission, while staged resections occurred less than 6 months apart. Outcomes included postoperative complications, length of hospital stay, and overall survival. Kaplan Meier survival estimates, Cox proportional hazard models and logistic regression were used. RESULTS: Among 2,738 patients undergoing resection for colorectal cancer liver metastases, 1168 (42%) had synchronous disease. Of these, 442 resections were simultaneous (38%) and 776 were staged (62%). The proportion of synchronous disease among patients undergoing resection increased on average 3% per year (p = 0.02). For simultaneous versus staged resection, respectively, median length of hospital stay was shorter (8 vs. 11 days, p < 0.001); rate of major liver resections was lower (17% vs. 65%, p < 0.001), major postoperative complications were similar (28% vs. 23%, p = 0.067), and 90-day post-operative mortality was higher (6% vs. 1%, p < 0.001). Chemotherapy was administered more commonly among patients undergoing staged resections (91% vs. 76%, p < 0.001). Simultaneous resection was associated with a lower median overall survival (40 months, 95%CI 35-46 vs. 78 months, 95%CI 59-86). Risk factors for lower survival included higher comorbidities, right-sided primary and simultaneous resection. CONCLUSION: Simultaneous resection was associated with similar postoperative complications, higher postoperative mortality and poorer long-term survival. Prospective randomized trials can inform the role of simultaneous versus staged resection for synchronous colorectal cancer liver metastases.
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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 | 0.000 |
| 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 | 0.001 | 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".