Rigid-platform transanal excision (TEM/TEO/TAMIS) for rectal neuroendocrine tumours: a single-centre TEM/TEO series and systematic review

Rectal neuroendocrine tumours (rNETs) are increasingly detected and often amenable to organ-preserving local therapy. Rigid transanal platforms (TEM/TEO/TAMIS) offer en bloc, full-thickness excision with precise margin control; however, contemporary evidence is limited. We report our single-centre outcomes and contextualise them with a focused, PRISMA-guided systematic review. We retrospectively analysed a prospectively maintained database of consecutive rNETs treated with TEM/TEO (1993–2025). The primary endpoint was R0 resection; secondary endpoints included complications, length of stay, residual tumour at completion excision, and oncologic outcomes. In parallel, we systematically searched PubMed/MEDLINE and Embase (last update August 1st 2025) for studies reporting outcomes of rigid transanal excision for rNETs (TEM/TEO/TAMIS/robotic TAMIS). Purely endoscopic series, radical resections, and case reports (< 5 patients) were excluded. Fourteen patients underwent local excision (median age 64 years; median distance from anal verge 7.5 cm). Tumour size was captured using two complementary metrics: preoperative endoscopic diameter (diameter pre) and histological diameter on the resected specimen (diameter histo), both reported in millimetres (mm). Median diameter pre was 20 mm (IQR 20–30; range 20–100), while median diameter histo was 30 mm (IQR 20–30; range 10–60). Histology revealed 10 G1 and 4 G2 tumours; lymphovascular invasion was present in 2 (14.3%). All procedures were completed transanally; the median operative time was 52 min, and the median stay was 2 days. One minor complication (Clavien–Dindo II) occurred. R0 resection was achieved in 14/14 (100%); among five completion excisions, residual tumour was present in 2 (40%). Over a median follow-up of 36 months (IQR 26–48; range 12–72), one patient (7.1%) recurred (nodal) and underwent salvage total mesorectal excision. The systematic review included 11 studies (~ 440 unique patients). Across series, R0 rates were typically 96–100%, morbidity was low (< 10%, mostly minor), and residual tumour at completion occurred in ~ 20–40% after incomplete endoscopic resection. Recurrences were uncommon but could occur late (> 10 years). Rigid transanal excision achieves high-quality local control with low morbidity and provides reliable full-thickness clearance after incomplete endoscopic resection. The combined presentation of our institutional series with a focused review clarifies where TEM/TEO/TAMIS most benefits rNET care—particularly for completion surgery and intermediate-risk lesions—within contemporary guideline frameworks.