학회 이름이 너무 길어서 외워지지 않습니다. "2nd SI-HUG symposium & 26th Annual Meeting of the Korean College of Helicobacter and Upper Gastrointestinal Research" 그냥 Helicobacter 2018 정도로 이름지으면 안 될련지... 여하튼 그 학회에서 meet the professor session을 합니다. 여러분의 많은 참석을 부탁드립니다.
일시: 4월 14일 (토)
강의 내용 중 도입 부분을 소개드립니다.
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.
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.