Endoscopic Treatment Strategy for Colorectal Tumors Proximal to the Appendiceal Orifice

Background: Endoscopic treatment for appendiceal orifice lesions is technically challenging due to anatomical structure, and the intraoperative perforation rate is relatively high, making appropriate treatment selection important. Our treatment strategy is based on history of appendectomy, appendiceal side visibility, malignancy findings, and lesion size. We have reported the utility of strip biopsy for benign tumors <10 mm involving the appendiceal orifice with a visible appendiceal side margin. For endoscopically challenging cases with deep appendiceal invasion and no history of appendectomy, we perform colorectal LECS. We evaluated the validity of our treatment strategy.
Methods: We reviewed 69 patients with appendiceal orifice lesions treated endoscopically at our institution from April 2012 to March 2025.
Results: Male/female: 40/29, median age 70(38-89). Twelve had a history of appendectomy. IIa/Is/Ip/Is+IIa: 65/2/1/1. Of the cases extending into the appendix, the appendiceal side was visible in 25 and not visible in 7. ESD/EMR/Strip biopsy/LECS: 53/3/11/2. Median operation time 47/16/10/130.5 minutes. Median size 21/10/10/14 mm. Complications: intraoperative perforation 1(ESD), PECS 4(ESD 3, Strip 1), but all were discharged without problems after conservative treatment. Pathological diagnosis: adenocarcinoma 8, adenoma 15, SSL 43, and hyperplastic polyp 3. Pathological margin negative 64, unclear 5(ESD 2, Strip 2, EMR 1).
Conclusion: Our treatment strategy, including strip biopsy and LECS, is effective with acceptable complication rate. We present our approach and techniques with video clips.