Outcomes of salvage surgery for anal squamous cell carcinoma: A systematic review and meta-analysis.
Bibliographic record
Abstract
3571 Background: Following primary chemoradiotherapy for squamous cell carcinoma of the anal canal (A-SCCa), 10% of patients have persistent cancer, and 30% develop local recurrence after initial complete response. Both persistent and recurrent A-SCCa may be amenable to salvage surgery, which typically involves intense health care resource utilization. Because only small cohorts have been reported, we synthesized the evidence for salvage surgery to gain a comprehensive understanding of outcomes. Methods: We systematically searched MEDLINE, Embase, and Cochrane Library (until October 11, 2018) for studies reporting on persistent or recurrent A-SCCa treated with salvage surgery. Quality assessment was performed using the Institute of Health Economics Quality Appraisal Checklist. Overall survival (OS) and disease-free survival (DFS) were pooled using two approaches: survival curve meta-analysis, and exact binomial likelihood random-effects model for survival probabilities. We used meta-regression, subgroup and sensitivity meta-analyses to explore sources of heterogeneity. Results: We identified 39 observational studies that included 1388 patients. Pooled 5-year OS was 45.5% (95% CI 40.6 to 49.9; 33 studies; 1308 patients), and did not differ in patients resected for recurrent (14 studies, n=259 patients) vs. persistent (n=238 patients) disease. There was no association of OS with study year, tumor size, or resection margin at the aggregate-level. Pooled 5-year DFS was 38.3% (95% CI 31.4-43.9; 14 studies; 554 patients). Pooled 30-day complications were 65.3% (95% CI 50.2-77.9; 17 studies; 720 patients): major complications 27.7% (95% CI 22.3-33.8), reoperations 12.7% (95% CI 8.7-18.2), and mortality 1.7% (95% CI 1.1-2.6%). Pooled perineal complications were 32.7% (95% CI 25.0-41.4). Conclusions: Salvage surgery offers 5-year OS of ≈45% and DFS of ≈40% for recurrent/persistent A-SCCa. Major complications and perineal wound complications are common, but postoperative mortality is rare. Presently, there are no reports of patient-reported outcomes such as quality of life after salvage surgery for A-SCCa. Comparative effectiveness studies comparing surgery to other treatments are warranted.
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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 | 0.011 | 0.023 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.016 | 0.043 |
| Bibliometrics | 0.007 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 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".