Association Between Hospital and Surgeon Volume and Rectal Cancer Surgery Outcomes in Patients With Rectal Cancer Treated Since 2000: Systematic Literature Review and Meta-analysis
Bibliographic record
Abstract
BACKGROUND: Previous reviews and meta-analyses, which predominantly focused on patients treated before 2000, have reported conflicting evidence about the association between hospital/surgeon volume and rectal cancer outcomes. Given advances in rectal cancer resection, such as total mesorectal excision, it is essential to determine whether volume plays a role in rectal cancer outcomes among patients treated since 2000. OBJECTIVE: The purpose of this study was to determine whether there is an association between hospital/surgeon volume and rectal cancer surgery outcomes among patients treated since 2000. DATA SOURCES: We searched PubMed and EMBASE for articles published between January 2000 and December 29, 2017. STUDY SELECTION: Articles that analyzed the association between hospital/surgeon volume and rectal cancer outcomes were selected. INTERVENTION: Rectal cancer resection was the study intervention. MAIN OUTCOME MEASURES: The outcome measures of this study were surgical morbidity, postoperative mortality, surgical margin positivity, permanent colostomy rates, recurrence, and overall survival. RESULTS: Although 2845 articles were retrieved and assessed by the search strategy, 21 met the inclusion and exclusion criteria. There was a significant protective association between higher hospital volume and surgical morbidity (OR = 0.80 (95% CI, 0.70-0.93); I = 35%), permanent colostomy (OR = 0.51 (95% CI, 0.29-0.92); I = 34%), and postoperative mortality (OR = 0.62 (95% CI, 0.43-0.88); I = 34%), and overall survival (OR = 0.99 (95% CI, 0.98-1.00); I = 3%). Stratified analysis showed that the magnitude of association between hospital volume and rectal cancer surgery outcomes was stronger in the United States compared with other countries. Surgeon volume was not significantly associated with overall survival. The articles included in this analysis were high quality according to the Newcastle-Ottawa scale. Funnel plots suggested that the potential for publication bias was low. LIMITATIONS: Some articles included rectosigmoid cancers. CONCLUSIONS: Among patients diagnosed since 2000, higher hospital volume has had a significant protective effect on rectal cancer surgery outcomes.
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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 | 0.008 | 0.026 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.012 | 0.024 |
| Bibliometrics | 0.007 | 0.010 |
| 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) | 0.002 | 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".