In recent years, peroral endoscopic myotomy (POEM) has been developed to treat achalasia and has so far provided promising outcomes. With a submucosal tunnel, myotomy of the lower esophageal muscle layer across the gastroesophageal junction and into the stomach can be completed in a minimal invasive mode during POEM procedure. Currently, POEM is becoming a widely applied procedure in many medical centres, which has been established as a minimally invasive alternative to conventional treatment modalities for achalasia.

However, the POEM procedure is technically demanding and associated with a steep learning curve. Therefore, training is most needed. POEM can have adverse effects such as insufflation-related events, bleeding, and wall-related injuries. However, they can be managed. Still, the rate of post-POEM gastroesophageal reflux disease seems a little higher, which might dampen the interest in this procedure. Moreover, we need to further evaluate long-term consequences. Reports of a POEM with more than five years’ worth of follow-up are still rare. Therefore, it is essential to focus on these key issues in clinical practice.

The aim of this Special Issue is to bring together original research and review articles discussing peroral endoscopic myotomy for achalasia. Submissions should explore the efficacy and safety of POEM for the treatment of gastrointestinal diseases. We especially welcome randomized controlled trials, retrospective studies with long-term follow-up, systematic reviews, and meta-analyses.

Potential topics include but are not limited to the following:

• Comparative studies of POEM to conventional treatment modalities
• Long-term studies of POEM for the treatment of achalasia
• Novel endoscopic equipment or devices developed for POEM
• Training models or methods for POEM
• Application of machine learning in the practice of POEM