Short-term Outcomes of Transanal Endoscopic Intersphincteric Resection for Locally Advanced Rectal Cancer after Neoadjuvant Chemoradiotherapy: A Single-Center Retrospective Cohort Study

OBJECTIVE:To compare the perioperative safety and specimen characteristics after transanal endoscopic intersphincteric resection (taE-ISR) versus classical intersphincteric resection (cISR) in patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (nCRT). METHODS:Clinicopathological data of 145 patients (75 undergoing taE-ISR and 70 undergoing cISR after nCRT) were retrospectively analyzed. Baseline characteristics, perioperative details, and pathological specimen quality of the two groups were compared. RESULTS:Intraoperative blood loss was lower in the taE-ISR group compared to cISR (50.0 (40.0-100.0) ml vs. 70.0 (50.0-100.0) ml, P = 0.034). Two patients (2.6 %) in the taE-ISR group and eight patients (11.4 %) in the cISR group sustained adjacent organ injury (P = 0.037). There was no statistically significant difference in the prevalence of postoperative complications between the two groups (17.3 % vs. 30.0 %, P = 0.072). However, pelvic abscess (1.3 % vs. 8.6 %, P = 0.042) and rectovaginal fistula (0.0 % vs. 5.7 %, P = 0.036) occurred less often in taE-ISR compared to cISR. The complete resection rate was higher in taE-ISR compared to cISR (98.7 % vs. 91.4 %, P = 0.042). No patients in taE-ISR had positive distal resection margins (DRM), while four patients in cISR had positive DRM (0.0 % vs. 5.7 %, P = 0.036). CONCLUSION:taE-ISR after nCRT was associated with higher-quality specimens, reduced intraoperative blood loss, and fewer perioperative complications, attesting to the feasibility and safety of taE-ISR In low-LARC patients.