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[Gastric cancer in Korea]
Good afternoon, ladies and gentlemen. It¡¯s a great honor for me to talk about current status of gastric cancer diagnosis and treatment in Korea. I¡¯d like to split my discussion into two parts. First, I want to cover the epidemiological aspect of the gastric cancer in Korea. Secondly, I will show you our experience of gastric cancer treatment in my institution.
In Korea, gastric cancer is the most common malignancy and the second most common cause of cancer-related deaths. In male patients, stomach is the most common site of cancer, followed by lung and colon. In female, stomach cancer is number three after thyroid and breast cancer.
The incidence of gastric cancer is still increasing. It has something to do with the facts that the proportion of elderly population is rapidly increasing.
As you can see in this figure, age-adjusted incidence of gastric cancer is slightly decreasing. However, the change is very slow.
The red arrow is the gastric cancer-related mortality. The blue arrow is the incidence of gastric cancer. As you can see, the mortality rate is rapidly decreasing.
This is the 5 year survival rate of gastric cancer in a few countries. It is not the stage-by-stage data, so the direct comparison is impossible. But, as you can see, treatment outcomes in the eastern and western countries are quite different.
One of the most unique aspect of the gastric cancer diagnosis in Korea is that we are doing national screening program since 1999. Starting at the age of 40, all Koreans are recommended to do the biennial gastric cancer screening with endoscopy or barium study. The cost is mostly covered by the government. The compliance is slowly increasing, and in a recent review, 70% of Koreans are doing gastric cancer screening by the national guideline. The screening modality is endoscopy in 63% and barium study in 36%. This is a huge workload for Korean endoscopists.
In the screening program, gastric cancers are usually found in 2 or 3 out of 1,000 endoscopic examinations. 75% of them are early gastric cancers.
The survival benefit of nationwide gastric cancer screening program is difficult to measure. There has been no randomized clinical trial using endoscopy for this purpose. However, there are a lot of indirect evidences, surrogate markers. For example, in this study from a large screening center in Seoul, T staging and N staging of gastric cancers found in regular screening program is much lower.
From now on, I¡¯d like to show you how we are doing in my institution. Excluding palliative surgeries, we have endoscopically or surgically treated more than seventeen hundred gastric cancers. Among them, 72% were early gastric cancers. In early gastric cancers, cases within absolute indications were 25%.
The evaluation of gastric cancers before final treatment decision is sometimes difficult. We reviewed the discrepancy between pre-treatment diagnostic groups and post-treatment diagnostic groups in terms of depth of invasion and absolute indications for ESD. As you can see in this slide, the rate of discrepancy is more than expected.
This is the treatment modalities for various gastric neoplasms by the pretreatment diagnostic groups. For early gastric cancers in the absolute indications, 90% were initially treated by ESD. Among them, additional surgeries were required in 16 percent. For early gastric cancers beyond absolute indications, 7 percent were initially treated by ESD. Among them, additional surgeries were required in 23%. In general, 20% of all gastric cancers were treated by endoscopy alone in our institution.
This flow diagram shows how we handled absolute indication early gastric cancers by the pretreatment diagnostic groups. Among 355 early gastric cancers initially treated by ESD, 119 cases, this is 34 percent, belonged to the beyond absolute indication group. Ten percent of patients in the absolute indication group were initially treated by surgery, and you can see the reason in the box at the right hand-side corner. Suspicious lymphadenopathy is the most common reason for surgery.
For the last 10 years, we did almost two thousand endoscopic resections for gastric cancers. In the technical aspects, the complete resection rate was 97% for cancers in the absolute indication, and it is 89% for beyond absolute indication cases.
Ladies and gentlemen, I'd like to wrap up my short presentation. Age-adjusted gastric cancer incidence is slightly decreasing in Korea. The proportion of early gastric cancer is increasing partly due to national screening program. Endoscopic submucosal dissection (ESD) is widely performed for early gastric cancer within indications.