講演情報
[SY8-8]Feasibility of Peranal Endoscopic Myectomy for Lower Rectal Lesions: A Single-Center Prospective Observational Study
*Takashi Kanesaka1, Yoshiaki Ando1, Shunsuke Yoshii1, Minoru Kato1, Yoshimi Tanaka1, Sachiko Yamamoto1, Koji Higashino1, Noriya Uedo1, Tomoki Michida1, Ryu Ishihara1 (1. Department of Gastrointestinal Oncology, Osaka International Cancer Institute, Japan)
Background: Although the usefulness of peranal endoscopic myectomy (PAEM) for lower rectal tumors has been reported, prospective studies on PAEM remain limited.
Methods: We conducted a single-center prospective observational study to evaluate the feasibility, safety, and preservation of anal function following PAEM. Patients with cT1 lower rectal cancer or lower rectal neuroendocrine tumors, as well as salvage cases diagnosed pathologically as having a positive or indeterminate vertical margin (VM1/X) after endoscopic resection, were enrolled. The primary endpoint was the technical success rate, defined as en bloc resection with histological confirmation of inner circular muscle inclusion. Secondary endpoints included procedure time, R0 resection rate, adverse events, and postoperative anorectal function.
Results: Between April 2024 and April 2026, 30 patients were enrolled, and PAEM was performed in 29 after excluding 1 patient with an upper rectal lesion (23 initial treatment cases and 6 salvage cases). The median age was 59 years (interquartile range [IQR], 53–73), with 14 males and 15 females. The technical success rate was 96.6% (28/29; 95% confidence interval [CI], 82.2–99.9%); 1 procedure was discontinued because muscularis propria invasion was suspected. The median procedure time was 73 minutes (IQR, 56–109), and the R0 resection rate was 86.2% (25/29). No severe intraoperative adverse events occurred, and delayed bleeding was observed in 1 patient (3.4%). The median Cleveland Clinic Incontinence Score was 0 preoperatively, 4 within 28 days postoperatively, and 0 thereafter, indicating transient deterioration of anal function with recovery to baseline after 28 days.
Conclusions: PAEM demonstrated a high technical success rate and may represent a feasible organ-preserving treatment option for selected lower rectal lesions.