KLASS (Korean Laparoendoscopic Gastrointestinal Surgery Study Group) trials: a 20-year great journey in advancing surgical clinical research for gastric cancer.

The Korean Laparoendoscopic Gastrointestinal Surgery Study Group (KLASS) trial series represents a comprehensive body of surgical clinical trials and studies focused on laparoscopic techniques in the treatment of gastric cancer. These trials, conducted and overseen by the KLASS, began with KLASS 01 in 2006 and have progressed to their 14th series as of December 2024. To date, approximately 36 papers, including pivotal publications, have been featured in high-impact journals, significantly advancing the field of gastric cancer treatment. Their findings have been incorporated into gastric cancer treatment guidelines in Korea, Japan, and China, underscoring their influence and clinical relevance. I take immense pride in being part of this remarkable journey, alongside esteemed seniors, colleagues, and numerous clinical researchers who initiated KLASS in 2004. This paper aims to review the studies conducted within the KLASS series to date and provide insights insight into the ongoing the ongoing research initiatives being developed by this esteemed group on their behalf.