Comparison of Functional Outcomes Between Robotic and Laparoscopic Surgery in Rectal Cancer Patients: Systematic Review and Meta-Analysis

44 studies, 6,121 patients: robotic rectal surgery shows no consistent advantage over laparoscopy for urinary or sexual function

Journal: Journal of Investigative Surgery | Published: 2026-04-27 | Type: Systematic Review, Meta-Analysis, Comparative Study | PMID: 42037577 Authors: Wang Yiwei, Wang Wenjing, Du Yu, Li Hui (Anorectal Department, Affiliated Hospital of Changchun University of Traditional Chinese Medicine) Funding/COI: Not listed for either

Summary

Robotic surgery costs more and takes longer than laparoscopy. The question is whether that buys anything for patients. This meta-analysis of 44 observational studies pooling 6,121 rectal cancer patients says: not really. Robotic surgery was associated with lower urinary retention, but the authors themselves flag publication bias as a likely explanation. At 3, 6, and 12 months post-op, urinary and sexual function were statistically indistinguishable between the two approaches.

Claims

• Robotic surgery associated with reduced urinary retention vs. laparoscopy, but effect may be driven by publication bias (funnel plot asymmetry detected on Egger's test)
• No significant difference in postoperative ileus between robotic and laparoscopic approaches
• Subgroup analyses at 3, 6, and 12 months: no significant differences in urinary function
• Subgroup analyses at 3, 6, and 12 months: no significant differences in sexual function
• Pooled results slightly favored robotic surgery overall, but effects described as "inconsistent, not sustained, and clinically modest"
• GRADE certainty of evidence: low (all 44 studies were observational)
• Study quality assessed with MINORS criteria; random-effects model used throughout

Study Quality

This is a methodologically careful meta-analysis. The authors searched four major databases (MEDLINE, Embase, Web of Science, CENTRAL) covering 2000–2025, used random-effects modeling to account for between-study heterogeneity, applied GRADE to rate evidence certainty, assessed bias with both funnel plots and Egger's test, and broke out subgroup analyses at clinically relevant time points. That's a competent toolkit.

The ceiling, however, is the input data: 44 observational studies. Observational data can't establish causation, and confounding is endemic — surgeons who choose robotic approaches may differ systematically from those who don't, and so may their patients. No amount of meta-analytic sophistication fixes that foundational problem. GRADE correctly rates this as low certainty, and the authors don't oversell it.

Red Flags

• All 44 included studies are observational — no RCTs; selection bias is uncontrolled
• Publication bias likely inflating the urinary retention finding; Egger's test flagged asymmetry
• Funding and COI not disclosed for this paper — a meaningful gap given that robotic surgery equipment is a high-stakes commercial market
• All four authors share a single institution (Changchun University of TCM), and none appear to have subspecialty urology or colorectal surgery affiliation — relevant to interpret methodological choices
• "Clinically modest" effects are acknowledged by the authors but not quantified with effect sizes or minimally important clinical differences in the abstract

Strengths

• Large pooled sample: 6,121 patients across 44 studies
• Broad database search with 25-year window
• Appropriate use of random-effects model given expected heterogeneity
• GRADE applied — rare in surgical meta-analyses
• Subgroup analyses at 3, 6, and 12 months add temporal resolution
• Authors are transparent about limitations and do not overclaim

Verdict

The honest takeaway from this paper is that robotic rectal cancer surgery does not clearly outperform laparoscopy for urinary or sexual function — and the one finding that leans robotic (urinary retention) is flagged as likely artifactual. That's a useful, if unsurprising, conclusion. The methodology is solid given what the underlying data allowed. What this paper cannot do, and doesn't try to do, is settle the question definitively: you'd need large-scale RCTs with prospective functional endpoints for that. As a summary of the current observational evidence, it's honest work in a field that needs more rigorous trials.