Transanal minimally invasive surgery (TAMIS) versus transanal endoscopic microsurgery (TEM) for local excision of rectal neoplasms: A systematic review and meta-analysis.

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.