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[2nd SI-HUG symposium & 26th Annual Meeting of the Korean College of Helicobacter and Upper Gastrointestinal Research]

일시: 2018년 4월 13일 (금) - 14일 (토)

장소: 콘래드호텔 서울

1. Meet the professor session - Truth and falsity of gastric cancer screening (Room A) - 이준행

"건강 검진은 秦始皇의 不老草다"라는 concept로 강의와 토론을 하였습니다. 長壽는 모든 사람의 꿈이지만 永生은 이룰 수 없습니다. 이룰 수 없는 꿈을 향하여 입증되지 않은 일을 하다가는 영생은 커녕 장수에도 지장이 생깁니다. 不老의 꿈을 위하여 아무 풀이나 먹다가는 藥草처럼 생긴 毒草를 먹고 일찍 죽게 될지 모릅니다. 남의 藥草가 내게는 毒草일 수도 있습니다. 중요한 것은 中庸입니다. Balance이지요. 무리한 검진은 생명을 단축시키기 쉽습니다. 삶의 질을 현저히 떨어뜨리기도 합니다. 속도를 줄입시다. 건진 살살합시다.


오늘 강의 중 가장 중요한 부분인 첫 part의 강의 내용입니다.

This is a picture of Qin Shihuang, the first Chinese emperor. He searched for immortality magic drug, but failed. Everyone want to live forever, or live as long as possible, but actually, no one can live forever. We just try, but always fail. The modern version of Qin Shihuang’s magic drug may be cancer screening. The organizing committee gave me a very difficult topic, the truth and falsity of gastric cancer screening. But, as you know, there is no magic answer for this challenging issue. Maybe I will fail, but I will try.

There are too similar terms which are quite confusing. One is 검진, which usually means cancer screening; the other is 건진, which means general health check-up. In Korea, 검진 and 건진 is widely used without clear definition or sometimes used interchangably. In my opinion, 검진, cancer screening belongs to the science, and the Korean government already established a huge and successful cancer screening program. On the other hand, 건진, health check-up belongs to the public’s hope or desire to live long with good health. A great parts of the general health check-up does not have a decent scientific evidence.

The aim of cancer screening is clear. We hope to detect cancers as early as possible and treat them completely. The outcome is to live longer or forever. But we should consider the cost-effectiveness issue in every cancer screening program.

Every screening is not always effective. A few years ago, I read an interesting article from New York Times by Richard J. Ablin, who discovered PSA, prostate specific antigen. He said the prostate cancer screening is an complete failure and he called his own scientific achievement as “the great prostate mistake.” Quote…

Another story. In Korea, thyroid cancer screening was a big issue. The thyroid cancer has been an epidemic due to widespread opportunistic sonographic screening. However, there was no change in the thyroid cancer mortality after a lot of thyroid surgeries. / Recently, thyroid cancer screening is not so much popular any more. New thyroid cancer patients are already decreasing.

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?

From now on, I will show you three scenarios. Green bar means advanced cancers. Blue bar means early cancers. This is the first scenario. By the cancer screening, advanced cancers decreased, and the early cancers increased. But the numbers of decreased advanced cancers and the increased early cancers are same. As a result, the total number was not changed. This is an ideal scenario of every cancer screening program, but it never happens.

The second scenario is more realistic. OK. The advanced cancers decreased a little bit, but the number of early cancers increased much more than that. As a result, we can see a huge increase of the total number of the target cancer. The overall mortality may decrease. But, do we need to treat all the early cancers?

The third scenario is a kind of nightmare. A lot of early cancers are found, the number of advanced cancers is the same. The treatment outcome may be the same. In this scenario, the screening may be useless.

For more insights, I recommend two articles. The first one is an opinion in Nature journal. It’s kind of a balanced idea.

The second one is a newspaper article from New York Times. It’s the most pessimistic idea about cancer screening. Professor Welch argues that doctors should focus on sick patients, not the healthy people.

[2018-4-14. 헬리코박터학회 meet the professor session에서 전성우 교수님의 질문]

75세 이상에서 검진 내시경을 권하지 말자는 가이드라인을 소개해 주셨습니다. 그러나, 75세 이상 노인들도 매우 건강한 분들이 많습니다. 건강한 고령자에서 위암을 발견하여 치료해 드리는 것은 의미있는 일이라고 생각합니다. 어떤 의견을 가지고 계시는지요?

[2018-4-14. 이준행 답변]

좋은 질문 감사합니다. 公과 私의 구분 이슈이면서 individualize의 문제입니다. 전국민을 대상으로 반강제적 검진을 push하기 위해서는 충분히 근거가 있어야 합니다. 득보다 해가 많은 것을 정부가 국민에게 권하거나 강제하면 안되기 때문입니다. 국민의 혈세로 진행되는 사업에서는 더더욱 명확한 근거가 있어야 합니다. 75세 이상 전국민을 대상으로 screening gastroscopy를 권하는 것은 근거가 없기 때문에 가이드라인에서 언급된 바와 같이 당장 중단되어야 마땅한 일입니다.

75세 이상이라도 충분히 건강하고 expected survival이 10년 이상인 경우는 screening gastroscopy를 권할 수 있습니다. 이를 위해서는 매우 정교한 정책이 필요하데, 우리나라에는 아직 이를 위한 data나 방법론이 확립되어 있지 않습니다.

반대로 75세 이하라도 건강하지 않고 expected survival이 10년 미만인 경우는 screening gastroscopy의 예외로 삼아야 합니다. 이를 위한 data나 방법론이 확립되어 있지 않은 것도 마찬가지입니다.

현 시점에서는 more and more를 추구하기에 앞서 잠시 속도를 줄이고 데이타를 모으면서 정책을 다듬어야 할 것입니다. Screening 문제를 정치적으로 접근하는 현재의 관행-이 또한 적폐입니다-을 청산해야 합니다. Screening은 건강 문제이고 의학 문제입니다. 퍼주기는 곤란합니다. 90세고 100세고 무조건 검진 딱지를 보내는 것은 국가 폭력이라고 생각합니다.

2. H. pylori and gastric carcinogenesis (David Y. Graham)

Abstract: Until recently gastric cancer was the most common cause of cancer deaths in the world. The discovery that gastric cancers were etiologically related to infection with H. pylori led to the realization that H. pylori eradication would prevent most gastric cancers. Gastric cancer is an inflammation-associated cancer with H. pylori infection being the cause of ongoing inflammation, rapid cell turnover and production of tissue damaging reactive oxygen and nitrogen species produced. Devolopment of cancer is related to progressive genetic instability which is one outcomes of chronic inflammation from any cause. The H. pylori organism itself is also directly involved in carcinogenesis through its ability to induce breaks in double-strand DNA, cause abnormal DNA methylation, and alter expression of microRNAs. The infection also stimulates activation-induced cytidine deaminase which can alter nucleotides. As one might expect, infections with strains causing a greater inflammatory response, such as those with an intact Cag pathogenicity island, are more often associated with development of cancer. However, infections with strains lacking all known virulence factors develop cancer. No proven cancer promoting bactrial factor has yet been discovered. Whether there is an important role of the infection in altering the local immune response to the cancer remains unknown but is suspected. Cancer risk is related to the degree and reversibility of gastric mucosal damage. After atrophy has developed the patient will have an increased risk of gastric cancer despite H. pylori eradication. The degree of risk increases exponentially with time, however the process can be stopped and partially reversed by H. pylori eradication. Gastric cancer can be largely eliminated by preventing H. pylori infection. Among those with H. pylori infection, the risk of developing gastric cancer can be also markedly reduced by treatment especially before the development of atrophic gastritis.

한 회사 부스에서 일회용 조직검사 겸자를 벌렸을 때 몇 mm인지를 보여주는 광고물을 보았습니다. 지름 2.0mm forcep인데 벌렸을 때 겸자 끝의 거리가 5.6mm라고 합니다. 회사마다 제품마다 조금씩 다르므로 자기가 가장 많이 사용하는 제품의 사양을 알고 있으면 좋겠습니다.

© 일원내시경교실 바른내시경연구소 이준행. EndoTODAY Endoscopy Learning Center. Lee Jun Haeng.