# KLASS-01

Source: https://onco.cc/trials/klass-01/  
OnCo record `klass-01` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

KLASS-01 showed that removing an early stomach cancer through keyhole surgery is as safe for long-term survival as open surgery and causes fewer wound complications, which made laparoscopic gastrectomy the standard for early gastric cancer in Korea and beyond.

## Summary

KLASS-01 was a multicentre non-inferiority trial run by the Korean Laparoendoscopic Gastrointestinal Surgery Study group in patients with clinical stage I gastric adenocarcinoma. Patients were randomised to laparoscopy-assisted or open distal gastrectomy with standard lymph node dissection.

The short-term report found fewer wound complications and similar mortality with the laparoscopic approach. The primary analysis, published in JAMA Oncology in 2019, showed that five-year overall survival after laparoscopic surgery was non-inferior to open surgery. With the Japanese JCOG0912 trial it settled the question for early distal gastric cancer; the follow-on KLASS-02 addressed locally advanced disease.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-17
- Tags: subtype-trials
- Registry id: NCT00452751
- Phase: 3
- Setting: Clinical stage I gastric cancer: laparoscopy-assisted distal gastrectomy against open distal gastrectomy, with five-year overall survival as the primary endpoint
- Sponsor: National Cancer Center Korea (Korean Laparoendoscopic Gastrointestinal Surgery Study Group)
- Enrolled: 1400
- Result: Laparoscopic distal gastrectomy was non-inferior to open surgery for five-year overall survival in stage I gastric cancer, with fewer wound complications.
- Outcomes: Overall survival at 5 years (non-inferiority): Laparoscopic distal gastrectomy 94.2% vs Open distal gastrectomy 93.3%; Cancer-specific survival at 5 years: Laparoscopic distal gastrectomy 97.1% vs Open distal gastrectomy 97.2%

## Sources

- ClinicalTrials.gov NCT00452751: https://clinicaltrials.gov/study/NCT00452751

## Connected records

- key papers: [JCOG0912: laparoscopy-assisted versus open distal gastrectomy for clinical stage IA or IB gastric cancer](https://onco.cc/key-papers/paper-jcog0912-katai-lancet-gastroenterol-hepatol-2020/), [KLASS-01: laparoscopic versus open distal gastrectomy for stage I gastric cancer, long-term survival](https://onco.cc/key-papers/paper-klass-01-kim-jama-oncol-2019/)
- cancers: [Early gastric cancer](https://onco.cc/cancers/early-gastric-cancer/), [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/)
- institutions: [National Cancer Center Korea](https://onco.cc/institutions/ncc-korea/)
- people: [Hyung-Ho Kim](https://onco.cc/people/hyung-ho-kim/)

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