S210 Risk of Perforation in Patients With Colorectal Cancer and Metallic Stents Who Received Bevacizumab Compared to Stent Alone or Non-Bevacizumab Chemotherapy: A Systematic Review and Meta-Analysis
Bibliographic record
Abstract
Introduction: Bevacizumab (BV) is a monoclonal antibody against vascular endothelial growth factor and is used to treat metastatic colorectal cancer (CRC). Although BV is an effective therapy for CRC and is generally well-tolerated, it can be associated with severe complications such as bowel perforation, gastrointestinal bleeding, or thromboembolism. Self-expanding metallic stents (SEMS) are used in obstructive CRC for palliative or preoperative purposes. There is a paucity of published literature on whether the risk of perforation is increased when chemotherapy - BV-based regimen in particular - is administered to patients with SEMS placement. We performed a systematic review and meta-analysis to determine whether BV-based chemotherapy is associated with higher risk of perforation in patients with SEMS. Methods: A comprehensive literature search was performed from major databases from inception to May 2023. The primary outcome assessed was the risk of perforation in BV+SEMS patients. The secondary outcomes assessed were the risk of bleeding in SEMS patients and non-BV+SEMS patients compared to BV+SEMS cohort. Pooled estimates were calculated using a random-effects model with 95% confidence interval (CI). The statistical analysis was performed by using CMA v 3.0 software (BioStat, Englewood, NJ). Results: There were 11 studies included, with BV+SEMS, SEMS only, and non-BV+SEMS therapies given in 293, 215, and 101 patients respectively. There were 9 retrospective cohort studies, 1 prospective cohort study, and 1 randomized controlled trial. Four studies were conducted in the US, 1 in Korean, and 2 each in Italy, Spain, and Canada. The mean age was 66.69±7.42 years. About 87.20% of patients had SEMS placed in the left colon, 4.89% in the transverse colon, and 7.93% in the right colon. The overall pooled rate of perforation in patients who received BV+SEMS was 18% (95% CI: 10.2%, 29.7%; P = 0.00; I2 = 64) (Figure 1). The risk ratios for developing perforation in BV+SEMS group was 1.56 (95% CI: 0.70, 3.47; P = 0.28; I2 = 0) when compared to SEMS alone group and was 3.52 (95% CI: 0.79, 15.62; P = 0.1; I2 = 42.5) when compared to non-BV+SEMS group. Conclusion: BV appears to increase perforation in CRC patients with SEMS, and is associated with a higher risk of perforation than those who received SEMS alone or SEMS + non-BV chemotherapy. Further randomized controlled trials and comparative analyses are needed to validate the findings of our study.Figure 1.: Forest plot for the pooled rate of perforation in patients who received bevacizumab and metallic stent for obstructive metastatic colorectal cancer.
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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 | 0.006 | 0.020 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.014 | 0.034 |
| Bibliometrics | 0.007 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".