Background: The World Health Organization has projected that by 2050, the global number of new cancer cases will reach 35 million [1]. In 2024, Mongolia ranks first in cancer mortality worldwide. As of 2024, Mongolia ranks 3rd globally for esophageal cancer with a rate of 19.8% per 100,000 people, and 1st for stomach cancer with a rate of 28.6% per 100,000 people [2]. In recent years, the number of new cases of esophageal and stomach cancers recorded in the population of Mongolia has been steadily increasing compared to other countries. According to statistical data in Mongolia, 8169 new cancer cases were registered in 2024, of which 4755 people died from cancer-related causes [3]. In 2024, 64.4% of cancer patients in Mongolia were diagnosed at a late stage, while only 35.6% were diagnosed at an early stage [4]. Compared to the previous year, early-stage cancer diagnosis increased by 65%, indicating an improvement in cancer detection. This progress is closely related to advancements in diagnostic methods. The development of medical technology, particularly the integration of advanced imaging features such as LCI (Linked Color Imaging) and BLI (Blue Light Imaging) into flexible endoscopy, has brought significant breakthroughs in endoscopic examinations [5]. Since 2023, the General Hospital of Khan-Uul District has been using the FUJINON 6000 model flexible endoscope from Japan, equipped with advanced imaging functions such as LCI (Linked Color Imaging) and BLI (Blue Light Imaging). The evaluation of the effectiveness of these technologies in accurately diagnosing early-stage cancers served as the basis for this study. Objective: The objective is to evaluate the accuracy of early-stage cancer detection using special light modes — LCI (Linked Color Imaging) and BLI (Blue Light Imaging) — among patients who underwent esophageal and gastric endoscopic examinations at the General Hospital of Khan-Uul District." Material and Method: In 2023 and 2024, a total of 4,842 patients underwent flexible endoscopic examinations of the esophagus and stomach at the General Hospital of Khan-Uul District. Among them, 82 patients with mucosal abnormalities or microvascular pattern changes in the esophagus, stomach, or small intestine were selected for retrospective analysis. Biopsies were obtained using advanced imaging technologies, specifically LCI (Linked Color Imaging) and BLI (Blue Light Imaging), to assess the diagnostic value of these modalities in detecting early neoplastic changes. Result: In 2023 and 2024, a total of 4,842 patients underwent flexible endoscopic examination of the esophagus and stomach at the General Hospital of Khan-Uul District. Among them, 82 patients with mucosal abnormalities were selected for further evaluation using LCI (Linked Color Imaging) and BLI (Blue Light Imaging), and biopsy samples were obtained. The findings were as follows:
• 18 cases of esophageal cancer were identified, of which 15 cases (83.3%) were early stage and 3 cases (16.6%) were advanced-stage.
• 26 cases of gastric cancer were detected, with 13 cases (50%) in the early stage and 13 cases (50%) in the advanced stage.
• 1 case of early-stage small intestinal cancer was also newly diagnosed.
All 28 early-stage cancer cases underwent endoscopic mucosal resection (EMR). The advantages of this procedure include minimal patient discomfort, no visible external wounds, low risk of bleeding or complications, and most importantly, organ preservation, which is a major clinical benefit. Conclusion LCI (Linked Color Imaging) and BLI (Blue Light Imaging) demonstrate greater accuracy in detecting mucosal abnormalities compared to conventional WLI (White Light Imaging) in the early diagnosis of esophageal and gastric cancers. Early detection of malignancies significantly improves patients’ quality of life and increases the 5-year survival rate to over 90%.