Short-term outcomes of endoscopic intermuscular dissection for early rectal cancer with deep submucosal infiltration:...

Endoscopic intermuscular dissection (EID) is an emerging technique for resecting early rectal cancer with deep submucosal infiltration. This study reports the short-term outcomes of EID for early rectal cancer from a single-center experience in China.

Between January 2024 and March 2025, 12 patients diagnosed with rectal malignant tumors, with CT staging ≤ T2 and no lymph node metastasis underwent EID. For lesions staged as cT2, endoscopic ultrasound confirmation of no muscularis propria invasion was required prior to EID for therapeutic resection at our center. All patients were evaluated by a multidisciplinary team and provided informed consent. The primary outcomes included technical success (defined as macroscopic complete en bloc resection without major intraprocedural complications), postoperative complications, and tumor-free resection margins. Secondary outcomes included hospital stay duration, follow-up completion rates, and short-term oncological outcomes.

Technical success was achieved in 11 of 12 patients (91.7%), with one patient experiencing an intraprocedural perforation. En bloc resection margins were confirmed histopathologically in all cases. One patient (8.3%) experienced delayed perforation requiring additional surgery. All lesions were confirmed as pT1b adenocarcinoma on final pathology. Among patients who reached follow-up timepoints, 6-month follow-up completion was 100% (9/9 eligible patients) and 12-month follow-up completion was 50.0% (2/4 eligible patients). No tumor recurrence was observed in patients with available follow-up data during a median follow-up of 9 months (range 3-16 months).

This preliminary single-center experience suggests that EID may be a feasible technique for carefully selected cases of resecting early rectal cancer with deep submucosal infiltration, demonstrating acceptable rates of complete resection and reasonable short-term safety profiles. However, the small sample size, staging limitations, and short follow-up period mean that these findings require cautious interpretation. Larger multicenter studies with extended follow-up periods are necessary to establish the role of EID in the treatment algorithm for early rectal cancer.