Efficacy and safety of extended duration to perioperative thromboprophylaxis with low molecular weight heparin on disease-free survival after surgical resection of colorectal cancer (PERIOP-01): multicentre, open label, randomised controlled trial
Bibliographic record
Abstract
OBJECTIVE: To determine the efficacy and safety of extended duration perioperative thromboprophylaxis by low molecular weight heparin when assessing disease-free survival in patients undergoing resection for colorectal cancer. DESIGN: Multicentre, open label, randomised controlled trial. SETTINGS: 12 hospitals in Quebec and Ontario, Canada, between 25 October 2011 and 31 December 2020. PARTICIPANTS: 614 adults (age ≥18 years) were eligible with pathologically confirmed invasive adenocarcinoma of the colon or rectum, no evidence of metastatic disease, a haemoglobin concentration of ≥8 g/dL, and were scheduled to undergo surgical resection. INTERVENTIONS: Random assignment to extended duration thromboprophylaxis using daily subcutaneous tinzaparin at 4500 IU, beginning at decision to operate and continuing for 56 days postoperatively, compared with in-patient postoperative thromboprophylaxis only. MAIN OUTCOME MEASURES: Primary outcome was disease-free survival at three years, defined as survival without locoregional recurrence, distant metastases, second primary (same cancer), second primary (other cancer), or death. Secondary outcomes included venous thromboembolism, postoperative major bleeding complications, and five year overall survival. Analyses were done in the intention-to-treat population. RESULTS: The trial stopped recruitment prematurely after the interim analysis for futility. The primary outcome occurred in 235 (77%) of 307 patients in the extended duration group and in 243 (79%) of 307 patients in the in-hospital thromboprophylaxis group (hazard ratio 1.1, 95% confidence interval 0.90 to 1.33; P=0.4). Postoperative venous thromboembolism occurred in five patients (2%) in the extended duration group and in four patients (1%) in the in-hospital thromboprophylaxis group (P=0.8). Major surgery related bleeding in the first postoperative week was reported in one person (<1%) in the extended duration and in six people (2%) in the in-hospital thromboprophylaxis group (P=0.1). No difference was noted for overall survival at five years in 272 (89%) patients in the extended duration group and 280 (91%) patients in the in-hospital thromboprophylaxis group (hazard ratio 1.12; 95% confidence interval 0.72 to 1.76; P=0.1). CONCLUSIONS: Extended duration to perioperative anticoagulation with tinzaparin did not improve disease-free survival or overall survival in patients with colorectal cancer undergoing surgical resection compared with in-patient postoperative thromboprophylaxis alone. The incidences of venous thromboembolism and postoperative major bleeding were low and similar between groups. TRIAL REGISTRATION: ClinicalTrials.gov NCT01455831.
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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 | 0.003 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.002 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 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".