Thirty years of transanal endoscopic microsurgery: a single-center experience

Abstract

Transanal endoscopic microsurgery (TEM) and transanal endoscopic operation (TEO) allow for organ-preserving removal of rectal neoplasms. However, changes in indications, anesthesia, and outcomes over time are not clearly defined. This retrospective review (1993–2025) of a prospectively maintained database categorized procedures into TEM (group A, 1993–2008), early TEO (group B, 2008–2016), and late TEO (group C, 2016–2025). Primary endpoint was uneventful 30-day course (no postoperative complications, readmission, reintervention, death) and secondary endpoints were intra-/postoperative complications, peritoneal entry, length of stay (LOS), readmission, mortality, reintervention, margins, and recurrence. Among 1077 transanal endoscopic procedures, 1048 were TEM/TEO with complete 30-day data (median age 69 years; 58% male; median lesion size 3 cm; median distance from the anal verge 6 cm). The primary endpoint (uneventful 30-day course) was achieved in 92.1% (group A: 92.9%, group B: 91.3%, group C: 92.1%; p = 0.75). Intraoperative complications occurred in 0.6%, postoperative complications in 7.9%, readmissions in 0.3%, 30-day mortality in 0.3%, and reinterventions in 2.8%, with no differences among groups. Median LOS decreased from 4 to 3 days ( p < 0.0001), while operative time remained around 60 min. Spinal anesthesia was used in 78.6% of late TEO cases. After adenoma excision ( n =563), R0 resection was 93.1% overall (96.5% in the latest era) and local recurrence was 6.9% overall (3.5% in the latest era); median time to adenoma recurrence was 12.0 months. Over three decades, TEM/TEO achieved consistent, safe outcomes with high R0 rates and minimal morbidity. Increased use of spinal anesthesia and technical refinements improved efficiency and shortened LOS without compromising oncological quality.