4th Mogolian Korean Joint Symposium (2023). 몽고 심포지엄. EndoTODAY 이준행

[The 4th Mogolian Korean Joint Symposium (2023). 제4회 몽고 심포지엄] - 終

한상욱 이사장님 인사말씀

1. 이준행 강의. Gastric ESD and incomplete resection (a lecture at Ulaanbaatar)

Thank you chairman for your nice introduction. It’s a great honor for me to talk in this prestigious meeting today.
Five years ago, we had the second joint symposium here in Ulaanbaatar.
At that time, I talked about Korean gastric cancer screening program.
And the dinner was very nice. Thank you very much for your hospitality.
After the joint symposium, I sometime hold web-based seminars with my friends in Mongolia.
First topic is indications.
Recently Korean Practice Guidelines for Gastric Cancer was released. Statement number 4 is about absolute indication. Endoscopic resection is recommended for well or moderately differentiated tubular or papillary EGCs with tumor size less than 2cm, mucosal cancer, and no ulcer.
The red box shows absolute indications.
Statement 5 is about expanded indications. Both ESD as well as surgery were equally recommended.
This is expanded indications. Both surgery and ESD can be done.
There are still some controversy about ESD for undifferentiated type early gastric cancers. What would you recommend for a 37 years old man with a small flat signet ring cell carcinoma?
I did an ESD.
The pathology was 13mm lamina propria cancer. A curative resection.
You can see the signet ring cells in the lamina propria with lymphoid follicles.
Currently, a prospective clinical trial about ESD for undifferentiated type early gastric cancer, ERASE-GC trial, is ongoing in Korea.
This is the current status of patient enrollment of the ERASE trial. The target is 708 patients and more than 500 were enrolled right now.
Statement 6 is about undifferentiated type early gastric cancers. It says ESD can be done, but cautiously and after sufficient discussion. The evidence level was low and the recommendation was conditional for.
Surgery is usually done, but ESD is currently performed in my institutions more often than before.
Next topic is the management of incomplete resection.
There are two types of incomplete resection. Risk of lymph node metastasis and lateral margin involvement.
Let me talk about the risk of lymph node metastasis first.
Regarding additional surgery after ESD, I’d like to briefly touch two aspects. First, can we predict the rate of non-curative resection requiring surgery more precisely? Second, is surgery always necessary for non-curative resection cases with lympho-vascular invasion?
A 75 years old gentlemen was referred for endoscopic treatment of early gastric cancer.
This is the outside pathology.
ESD was done as usual.
ESD pathology was mixed histology, 24mm, 400um SM invasion, and lymphatic invasion.
This is moderately differentiated adenocarcinoma.
This is poorly differentiated solid component.
Areas of submucosal invasion was differentiated type.
There were multiple lymphatic invasions.
Surgery was done. In the final pathology there was a lymph node metastasis in perigastric lymph node stations.
In the upper right node, the nodal structure was destroyed.
This is a close up for lymph node metastasis.
Can we predict the rate of non-curative resection requiring surgery more precisely?
We developed a risk scoring system.
We found six independent variables such as pathology, size, axial location, circumferential location, macroscopic morphology, and ulcer. Based on the relative risk we made a score for each variables.
This is the correlation between the total risk score and the predicted risk of non-curative ESD requiring gastrectomy.
In the previous case, the score was 9 and the risk of non-curative ESD was 63.5%
At my institution at Samsung Medical Center, gastric ESD is done about 1,000 cases a year. In the recent 5 years, the rate of gastric cancer among ESD cases was 73%. The rate of additional surgery after ESD for gastric cancer was 15%.
Survival benefit of additional surgery after incomplete ESD is well established by many reports including our experience at Samsung Medical Center. In terms of the overall survival, additional surgery was related with better outcome.
In the surgically resected specimen, residual tumor is found in about 10-20%. In our experience, the rate of lymph node metastasis was only 5.7%.
The most important risk factor of lymph node metastasis is the lymphatic invasion followed by the size, positive vertical margin and vascular invasion. So surgery is strongly recommended for lymphatic invasion cases.
However, do you think surgery is necessary for mucosal cancer with lympho-vascular invasion? Red box is the traditional absolute indication group. In the SMC cohort, there was no lymph node metastasis after the surgery. Careful observation without additional surgery can be an option for this group of patients.
This is an example. There was a minor lymphatic vessel involvement for a small EGC with differentiated-dominant mucosal cancer. What’s your opinion?
We had a discussion with the patient, and finally decided to observe carefully without additional surgery.
Three years after the ESD, there was no recurrence.
The second type is the lateral margin involvement.
Regarding the lateral margin positive issues, either early additional ESD or ablation can be done. In highly selected cases, careful observation without any additional treatment is a possible option.
In my institution, the overall rate of positive lateral resection margin was 5 percent. Early additional ESD was done in 16 cases.
This is an example of early additional ESD for positive lateral margin.
This is another example. Outside biopsy was moderately differentiated adenocarcinoma.
The border was not clear and submucosal invasion was suspicious in EUS. We recommended surgery, but the patient wanted endoscopic treatment.
ESD was done but the pathology was 48mm mixed type mucosal cancer with lateral margin involvement.
Early additional ESD was done and there was 22mm sized residual cancer.
There was no recurrence during 5 year follow period.
Early additional ablation is another important treatment option. In this case, posterior resection margin was positive.
Ablation treatment with argon plasma coagulation was done. There was no recurrence in the follow-up endoscopy.
Ladies and Gentleman, I’d like to conclude my short presentation. Additional surgery is the standard treatment for cases with risk of lymph node metastasis. Most lateral margin positive cases can be successfully treated with additional endoscopic measures, such as secondary ESD or ablation.
I hope to see you again at KINGCA this September in Seoul. 바힐ㄹ따. Thank you.

2. 심포지엄 노트

몽고에서는 proximal gastric cancer가 많아 total gastrectomy가 주 수술입니다.
양한광 교수님의 key note lecture. One team을 강조하셨습니다.
비만 수술에서 sleeve gastrectomy보다 bypass 수술이 diabetic control에 유리하여 최근에는 resectional R-Y gastric bypass를 하는 경우가 많습니다.
Robotic gastrectomy에서 energy device를 사용하기 어려운 점이 있어서 일본에서는 bipoloar를 사용하여 결과를 낸 후 보험을 적용하기 시작하였다고 합니다. 우리나라는 아직 비보험.
Naive에서는 CLA 내성이 23.5%, MET 내성이 25.9% 이지만 treatment failure에서는 가각 85%, 57%로 높아집니다.
Marker 기반의 치료, IO (immuno-oncology)에 대한 관심이 높습니다.
이혁준 교수님의 KLASS trial 소개

3. 학회 전후

2023-7-1. National Cancer Center Mongolia 방문하여 원장님과 함께
2023-7-1. National Cancer Center Mongolia. 원장님방에서
아침 산책. 징키스칸 광장
Hutsai national park
Hutsai national park

Hutsai national park에서의 모험

[References]

1) SMC-Mongolian NCC Joint Seminar 삼성서울병원 몽고국립암센터 세미나
2) 제2회 몽고 한국 Joint Symposium (2018)