Principles of disease screening

The core underlying principle of disease screening has never been “early detection and early treatment, the more the better”; The benefits should always outweigh the potential risks, be adapted to individual health characteristics and needs, all projects should be supported by clear evidence-based medical evidence, and the final decision should be made by informed doctors and patients. ——This is the largest consensus currently reached by the global public health field and clinical community, and all remaining specific implementation standards are extended around these four points.

Many people may not believe it, but I encountered this example when I was doing free clinics in the community two years ago: 52-year-old Aunt Zhang is usually in good health and does not even have high blood pressure. After listening to the sales advice of the physical examination agency, she spent more than 10,000 to do a full set of early tumor screening plus PET-CT, and the result was found to be a 3mm tumor on the lung. She had a ground glass nodule, and the report said "the possibility of malignancy cannot be ruled out." She was so frightened that she lost 8 pounds in half a month, and went to three hospitals for examinations. In the end, the doctor asked her to follow up for six months.

At this point, I have to mention the controversy that has been going on in the screening field for almost ten years: one group is the relatively radical early screening group, which advocates expanding screening coverage as much as possible and lowering the starting age for screening. For example, some scholars from the American College of Physicians also proposed in 2021 that the starting age for lung cancer screening should be lowered from 55 to 40 years old, covering all people with a smoking history of more than 10 years. Their core argument is that early detection of one case of early cancer can save hundreds of thousands of later treatment costs and save a life.； But the views of the other conservative faction are also very strong. The data of a study covering 230,000 people published by "Lancet Public Health" in 2023 is here: low-risk groups undergo low-dose spiral CT lung cancer screening every year. For every lung cancer death that is reduced, 370 people will have false positive results, and 18 people will receive false positive results. Unnecessary invasive biopsies, and nearly a thousand people will suffer from cancer anxiety for a long time because of the positive results, which will lead to problems such as insomnia and high blood pressure. "In order to save one person, hundreds of people suffered in vain. It has not yet been determined whether this account can be paid." This is what the senior experts in our institute often say.

In fact, despite all the quarrels, the essence still cannot get around the core criterion of "the benefits outweigh the risks." For example, it is also a low-dose spiral CT. If you have a 20-year smoking history, smoke 1 pack a day, and have a family history of lung cancer, then you can have it checked every year starting from the age of 40. The benefits are dozens of times the risk, and it is completely worth it. ； But if you are a 28-year-old non-smoker and no one in your family has lung cancer, and your work unit prescribes this project for your physical examination, the risks simply outweigh the benefits. It is better to save money and have two more oral examinations.

Another pitfall that many people easily fall into is those Internet celebrity screening programs that are so hyped that "one drop of blood detects 12 types of cancer" and "saliva detects gastric cancer risk", which can easily cost thousands or tens of thousands. In fact, there is basically no clear evidence-based medical support. To put it bluntly, they charge an IQ tax. Last year, I met a young man who had just started working. He spent 8,800 on a so-called early screening for all cancers. The result showed a high risk of pancreatic cancer. He was so scared that he didn't sleep well for a week. He came to me and asked me what to do. I asked him to do a contrast-enhanced CT and endoscopic ultrasound. Currently, the mainstream global guidelines clearly recommend routine screening programs for the general population. In fact, they only include lung cancer, breast cancer, colorectal cancer, cervical cancer, and prostate cancer. Others are either only targeted at high-risk groups, or are still in the clinical trial stage and have not yet been widely used.

Oh, by the way, another point that is easily overlooked is that screening programs for different groups of people cannot be directly copied. In the past few years, many domestic institutions copied European and American breast cancer screening guidelines and asked women over 40 to undergo mammography every year. Later, they slowly discovered that something was wrong: Asian women's breasts are generally denser than European and American women, mammography has poor penetrating power, and the false positive rate is more than 30% higher than that of European and American people. For Asian women under 40 years old, breast ultrasound is more profitable. This is a typical manifestation of "adapting individual characteristics". Don't worry about any imported guidelines, the one that suits you is the right one.

As for the point of informed and joint decision-making, it is not a false statement. A big brother came to me before and asked if he should have a colonoscopy. The calculation I made for him was: you are 48 years old, have no family history of bowel cancer, and have normal bowel movements. The benefit of a colonoscopy is that it can detect adenomas and early cancers in advance. The risk is about one in a thousand of intestinal perforation, and there is also the trouble of having to take laxatives all afternoon. It is your choice whether to do it or not. In the end, he found it troublesome and chose to do fecal occult blood first, and then do a colonoscopy if it was positive. This is good. You have to be willing to accept this plan for your own body. You can neither be forced by the doctor, nor can you be fooled by salesmen who tell you how expensive it is.

I have been engaged in the prevention and control of chronic diseases for almost 10 years. I have seen too many people suffer from anxiety due to over-screening, and I have also seen too many people who should have been screened and failed to do so. To put it bluntly, screening is actually like buying insurance: you would not buy pension insurance for a child who has just started elementary school, nor will you buy children's critical illness insurance for someone who is about to retire. Don't be greedy for more, don't listen to marketing claims, and choose the appropriate items based on your own living habits and family history, which is the most reliable.