Meta-analysisindependent cross-checkabstract checked★ key study I-BAR-119 in-depth review
Meta-analysis: upper digestive cancers after weight-loss surgery
Upper gastrointestinal cancer risk following bariatric surgery: meta-analysis.
Overview
Cooke et al.. BJS Open 2025 · PMID 41947341 · DOI 10.1093/bjsopen/zrag006
People who had surgery had about 40% fewer upper digestive cancers, including cancer of the gullet.
Does the study support the specific claim? No · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Upper GI cancer after surgery
- How was the study done?
Meta-analysis
- How many people, animals or samples were studied?
>5.7 million
- What was actually found?
Lower risk
- How large was the observed effect?
RR 0.58
- What do the results mean in everyday life?
No sign of earlier cancer
- What are the study's limitations?
Observational, mixed procedures
- What does it say about Elawady's specific claim?
Contradicts the claim
- Do the results apply to Germany and Europe?
Applicable
- What can explicitly not be concluded from this study?
Sleeve-only data
Scientific in-depth review
1. Full reference
- Authors
- Cooke et al.
- Journal
- BJS Open
- Year
- 2025
- Identifier
- PMID 41947341 DOI 10.1093/bjsopen/zrag006
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref API
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Funding: Cancer Research UK, NIHR Imperial BRC (PubMed grants).
2. Research question
Is bariatric surgery associated with upper gastrointestinal cancer risk?
3. Study design and population
- Study design
- Meta-analysis – Systematic review and random-effects meta-analysis
- Population
Patients with obesity with or without bariatric surgery
- Country
Multinational
- Period
Search to July 2025
- Sample size
20 studies; 1,173,113 surgical and 4,600,719 nonsurgical patients
- Inclusion and exclusion criteria
Studies reporting oesophageal, gastric, liver, pancreatic, gallbladder, biliary or small-intestinal cancer
4. Methods and endpoints
- Exposure / intervention
Bariatric surgery
- Comparator
No surgery
- Endpoints
Upper GI cancer incidence
- Statistical methods
Pooled RR, random effects
5. Actual results
- Results
Overall upper GI cancer RR 0.58 (0.48-0.71); oesophageal RR 0.63 (0.40-0.98); liver RR 0.47 (0.35-0.61); gallbladder RR 0.33 (0.17-0.65); no significant association for gastric or pancreatic cancer.
- Absolute risks
not reported in abstract
- Authors' conclusion
Bariatric surgery appears to reduce oesophageal, liver and gallbladder cancer risk; reporting by procedure type is needed.
6. Strengths
- Very large pooled sample
- Recent (2025)
7. Weaknesses
- Observational studies
- Procedure types not separated
- Abstract only
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Overlaps with other cancer meta-analyses.
9. Assessment of the statistical interpretation
Oesophageal RR upper bound 0.98 - borderline.
10. Relevance to the specific claim
Even for oesophageal cancer (the main theoretical concern after sleeve), pooled risk is lower after surgery.
11. Independent contrary findings
Not sleeve-specific.
12. Transferability to Germany and Europe
Includes European cohorts.
13. Overall methodological judgement
Supports lower upper-GI cancer risk overall.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | indirect |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Sleeve-specific oesophageal cancer.
15. Linked fact checks
- Sleeve gastrectomy makes cancer appear decades earlier (it 'kills' and brings cancer forward). – Studies contradicting or limiting the claim