Transanal minimally invasive surgery (TAMIS) versus transanal endoscopic microsurgery (TEM) for local excision of rectal neoplasms: A systematic review and meta-analysis.
TL;DR
Low-certainty evidence suggests TAMIS may shorten operative time and reduce 30-day morbidity compared with TEM/TEO, but the evidence is very uncertain regarding resection quality, peritoneal violation, and long-term oncologic outcomes.
Abstract
Background
Local excision techniques, including transanal endoscopic microsurgery (TEM) and transanal minimally invasive surgery (TAMIS), are widely used for selected rectal neoplasms, though direct comparative evidence remains limited.
Methods
A PRISMA-guided systematic review and meta-analysis (PROSPERO CRD420251125364) searched MEDLINE, Embase, Scopus, and Cochrane CENTRAL for comparative studies of TAMIS versus TEM/TEO. Primary endpoints were resection quality and a harmonised composite "poor-quality resection" endpoint (R1 margin and/or specimen fragmentation). Random-effects meta-analysis used the Hartung-Knapp-Sidik-Jonkman adjustment; certainty of evidence was assessed using GRADE.
Results
Four studies met inclusion criteria (TAMIS n = 341; TEM/TEO n = 409). Pooled estimates showed no difference in positive margins (RR 1.22, 95% CI 0.52-2.85), specimen fragmentation (RR 1.38, 95% CI 0.33-5.78), or the composite poor-quality endpoint (RR 1.24, 95% CI 0.05-28.23; k = 2, wide interval reflecting HKSJ variance inflation at small k), all of very low certainty. Overall 30-day morbidity favoured TAMIS (RR 0.75, 95% CI 0.61-0.93; low certainty). TAMIS was associated with shorter operative duration (MD -36.4 min, 95% CI -46.2 to -26.5; low certainty). Observed length-of-stay differences likely reflected institutional perioperative pathways rather than platform-specific recovery.
Conclusion
Low-certainty evidence suggests TAMIS may shorten operative time and reduce 30-day morbidity compared with TEM/TEO. The evidence is very uncertain regarding resection quality, peritoneal violation, and long-term oncologic outcomes. These findings neither establish equivalence nor identify a decisive advantage for either platform; selection should continue to reflect local availability, cost, and surgeon experience. Prospective, ideally randomised, comparative studies with harmonised endpoints and patient-reported functional outcomes are now the priority.