Endoscopic submucosal dissection for laterally spreading tumors involving the appendiceal orifice

Since the endoscopic resection of laterally spreading tumors (LSTs) involving the appendiceal orifice remains technically difficult, such lesions are usually treated by surgical resection. However, with recent advances in endoscopic devices, endoscopic submucosal dissection (ESD) has become feasible and may be safely performed even for lesions involving the appendiceal orifice. Therefore, in order to assess the validity of endoscopic treatment for such lesions, we retrospectively evaluated the safety and efficacy of ESD.

A total of 30 patients with LSTs extending to within 10 mm of the appendiceal orifice (Group AO) and 122 patients with cecal LSTs located away from the appendiceal orifice (Group C) who were treated between December 2011 and September 2015 were retrospectively enrolled in the present study. The indications for ESD were determined by the preoperative endoscopic diagnosis made on the basis of Kudo's pit pattern classification. Based on these preoperative endoscopic diagnoses, 8 of the 30 enrolled patients underwent surgical resection as the initial treatment, because the tumor showed deep invasion beyond the orifice and/or a VN pit pattern was visible. The treatment outcomes (en bloc R0 resection rates, tumor size, procedure time, and complication rates) were compared between the two groups.

The sensitivity and specificity for the cancer diagnosis were 81.8 and 94.7%, respectively. There was no significant difference in the en bloc R0 resection rate between Group AO and Group C (90.9 vs. 95.9%, P = 0.23). Furthermore, there were also no differences in the mean tumor size (30.0 ± 20.8 vs. 34.9 ± 14.5 mm, P = 0.17) or mean OR time (55.0 ± 39.2 vs. 58.9 ± 48.2 min P = 0.72) between the two groups. One case from Group AO (4.5%) was complicated by a perforation, which was successfully managed endoscopically.

Although proficiency in endoscopic techniques is required, our results indicate that LSTs involving the appendiceal orifice can be successfully treated by ESD.