Post written by Katsuro Ichimasa, MD, PhD, from the Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.

We present a groundbreaking advancement in the management of early lower rectal cancer through peranal endoscopic myectomy (PAEM), also known as endoscopic intermuscular dissection, in our recent publication in GIE.

Traditional endoscopic methods such as endoscopic submucosal dissection often struggle with T1 cancers because of a high rate of vertical margin positivity sometimes exceeding 30%. PAEM offers a solution by enabling precise dissection between the inner circular and outer longitudinal layers of the muscularis propria. This results in higher R0 resection rates and improved pathological assessment and potentially reduces the need for additional surgery.

One of the most exciting implications lies in PAEM’s potential role for T2 cancers. By integrating artificial intelligence—based models to predict lymph node metastasis, PAEM could allow for local treatment followed by risk-stratified surveillance, avoiding invasive surgery in selected low-risk patients.

Despite being technically challenging, PAEM has demonstrated high success rates and a favorable safety profile when performed by skilled endoscopists. The article also highlights thoughtful indications for its use, particularly in elderly or comorbid patients for whom surgery is not an option.

This study not only advances the field of therapeutic endoscopy but also paves the way toward personalized, minimally invasive care in colorectal oncology.

 A, A 10-mm lesion in the lower rectum. B, Intermuscular dissection between the inner circular and outer longitudinal muscular layers. C, Resection site after peranal endoscopic myectomy. D, Suturing the defect of the inner circular muscle with clips.

Read the full article online.

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