Gastric cancer screening in Korea Gastric cancer is the most common malignant disease in males, and the number 4 in females. The incidence of gastric cancer in Korea is slowly decreasing, but the mortality rate is rapidly decreasing. In 2013, the mortality/incidence ratio was 0.31 in Korea. In 1996, 10-Year National Plan of Cancer Control was launched. In 1999, National Cancer Screening Program for stomach, breast, cervical cancer started for members of lowest income family. It was free of charge. In 2005, trget population was expanded to the lower 50% of National Health Insurance beneficiaries. In 2006, screening for upper 50% income group started with 20% self payment. So, there are two systems running together. One is National Cancer Screening Program and the other is National Health Insurance Cancer Screening Program. National cancer screening program is for members in lower income family, and everything is free. National health insurance cancer screening program is for member of higher income family, and they should pay 10%. Most of the public budget comes form national health insurance. It is 90 percent. National government pay 5 percent, and local government pay another 5%. Regarding the governance structure, National Cancer Center develops the screening strategy, and the national health insurance corporation and public health center actually run the program. The gastric cancer screening starts at the age of 40. Interval is every 2 years. The standard method is endoscopy. If endoscopy is not available, upper GI series is the secondary choice. The most important issue is the screening interval. Currently 2 year interval is recommended. However, scientific evidence is not enough. The second issue is upper age limitations. In the academic guideline, the upper age limit for gastric cancer screening is 75. However, in the government program, there is no upper age limitations. The policy change seems to be very difficult. All kinds of medical institutions participate in the gastric cancer screening program. General hospitals, small hospitals, primary clinics, and screening institutions are doing gastric cancer screening. One special aspect of Korean cancer screening is opportunistic screening. It¡¯s not a national, public, mass screening program. It is a personal, private program, and the cost is not covered by the government. It¡¯s usually expansive. The proportion of opportunistic, private screening is about 30%. The participation rate of gastric cancer screening for the organized national program is about 45%. Including the opportunistic private screening program, the rate is about 75%. In the gastric cancer screening, the rate of endoscopy is about 80%. Upper GI series is about 20%. Gastric cancer detection rate by national cancer screening program by EGD or UGIS is about 1.4 out of 1,000 during 2002 and 2011. In that period, endoscopy and upper GI series was done half and half. When the screening is done by endoscopy, the gastric cancer detection rate is 3 out 1,000. 75% is early gastric cancers. There are two important biases in the cancer screening. The first one is very famous, the lead time bias. I think all individuals in this room already understand this type of bias. Even if we may detect cancers earlier, the overall survival gain is another issue due to the lead time bias. The second bias is the length-time bias. It means cancers detected in the screening program may be less aggressive. This bias is especially important for the elderly population. If some cancers in the elderly people are very slow-growing, is there any reason that we need to find them? And recently published in the Gastroenterology journal. The primary outcome was gastric cancer specific mortality. In average, the gastric cancer specific morality reduction was 21%. In the age group between 40 to 74 was 47%. So, in our early experience, half of the gastric cancer death can be prevented by national screening program. The methods and frequency matters. The mortality reduction was 81% by repeated endoscopy, and 21% by repeated upper GI series. By endoscopy, the effect of mortality reduction remained by 48 months from the cancer diagnosis to the last screening. This data supports 2 year interval.