Abstract 738: Long-term survivorship between gastrectomy and endoscopic resection for gastric cancer using a nationwide real-world database: 15 years of follow-up
Authors: Woo Hyeong-taek , Kang So Hyun , Baek Ji Yoon , Yoo Mira , Hwang Duyeong , Lee Eunju , Park Young Suk , Ahn Sang-Hoon , Kim Nayoung , Lee Dong Ho , Kim Hyung-Ho , Shin Aesun , Suh Yun-Suhk 
Published: June 2023

Abstract
Introduction: Nutritional deficiency and weight loss after gastrectomy are important detrimental factors for gastric cancer survivorship, which is avoided by endoscopic resection (ER). On the other hand, chronic metabolic or cardiovascular diseases in long term survivors may require appropriate weight reduction. The purpose of this study is to evaluate long term survival, cumulative incidence, and medical expenses of chronic diseases between gastric cancer survivors who underwent gastrectomy and ER using the Korean National Health Insurance (KNHI) database.
Methods: Big data of patients treated by either gastrectomy or ER for gastric cancer were restructured from 2008 to 2015 through the KNHI database which covers the entire Korean population. Those who had other primary cancer within 3 years before the treatment, received chemotherapy or radiotherapy, or had gastric cancer as the cause of death in death certificates were excluded. After 2:1 propensity score matching by age, sex, Charlson Comorbidity Index, insurance premium quartiles, and year of treatment, gastrectomy and ER groups were compared for 15-year survival, and incidence of new chronic diseases including major adverse cardiovascular events (MACE). MACE-3 was defined as first occurrence of all-cause mortality, ischemic heart disease, and cerebrovascular events, and MACE-6 as MACE-3 plus heart failure, nephropathy, and atrial fibrillation.
Results: After matching, 49,578 survivors for the gastrectomy group and 24,789 for the ER group were analyzed. The gastrectomy group showed significantly higher risk of death by respiratory diseases (HR 1.37, 95% CI 1.18 - 1.35, P &lt; 0.0001) including pneumonia (HR 1.62, 95% CI 1.32 - 2.00, P &lt; 0.0001), and external causes such as trauma (HR 1.38, 95% CI 1.16 - 1.63, P &lt; 0.0001), but lower risk of death caused by other cancers (HR 0.85, 95% CI 0.77 - 0.95, P &lt; 0.0001) especially obesity-related cancers including liver, bile duct, gallbladder, and pancreatic cancer. There was no difference in risk of death by other ICD-10 diseases between the two groups. Gastrectomy group showed significantly lower incidence of hypertension (HR 0.65), ischemic heart disease (HR 0.84), heart failure (HR 0.80), and cerebrovascular diseases (HR 0.79) than the ER group. The gastrectomy group had lower risk of MACE-3 (HR 0.86, 95% CI 0.83 - 0.89, P &lt; 0.0001) and MACE-6 (HR 0.86, 95% CI 0.83 - 0.89, P &lt; 0.0001).
Conclusion: The gastrectomy group showed lower risk of MACE and obesity-related cancers with less medical care expenses for diabetes or hypertension, but had higher risk of death by pneumonia or external causes than the ER group in Korea.
Citation Format: Hyeong-taek Woo, So Hyun Kang, Ji Yoon Baek, Mira Yoo, Duyeong Hwang, Eunju Lee, Young Suk Park, Sang-Hoon Ahn, Nayoung Kim, Dong Ho Lee, Hyung-Ho Kim, Aesun Shin, Yun-Suhk Suh. Long-term survivorship between gastrectomy and endoscopic resection for gastric cancer using a nationwide real-world database: 15 years of follow-up [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 738.