The purpose of disease screening is to early detect patients who are still in the latent period of disease

Yes, from the day it was born, the core purpose of disease screening is to detect patients who are still in the incubation period early - to put it bluntly, it is to catch the disease before it appears and before you feel anything abnormal, so as to minimize the cost of treatment and reduce physical damage.

When I was stationed in the community public health department in the past two years, I came across a particularly impressive example: 62-year-old Aunt Zhang in the community usually danced square dances with more energy than young people. She said that she had regular bowel movements and never had gastrointestinal problems. The community promoted free colorectal cancer screening. She found it troublesome to take stool samples and hid three times without coming. In the end, a grid officer came to the door and squatted for half an hour before convincing her to do a fecal occult blood test. The result came out weakly positive, so we followed her for a colonoscopy and found a 0.9-cm adenomatous polyp in the ileocecal area. Mild dysplasia had already appeared. If it takes another two to three years, there is a high probability that it will develop into advanced intestinal cancer. The polyps were removed under the microscope. Now my aunt takes the initiative to do screenings every year and tells everyone she has saved a life.

However, the debate over whether screening is an IQ tax has actually continued over the years. The basis for those who oppose large-scale universal screening is also very solid: the most typical example is that many European and American countries have suspended prostate-specific antigen (PSA) screening for the general population in the past few years. Data shows that for every 1,000 men over the age of 55 screened, more than 100 people will have false positive PSA results, of which at least 100 men will have false positives. At least 20 people will undergo an invasive prostate puncture in vain, and many of the detected low-risk prostate cancers themselves progress very slowly. They may not show symptoms until the patient dies at the age of 80. Instead, he will suffer lifelong sequelae of urinary incontinence and sexual dysfunction due to subsequent surgeries and radiotherapy. It is completely worth the loss.

In fact, in the eyes of those of us who have been working in public health at the grassroots level for more than ten years, both views are correct. The problem is not “whether screening should be done”, but “how to do screening and for whom”. There is a jargon we often say in private: Screening is not about casting a big net to catch fish, it is about finding the corresponding fish pond with a fishing rod. If you ask a 20-year-old girl who has never smoked and has no family history of lung cancer to undergo a low-dose chest CT every year, it is simply a waste of radiation. ； But if you do it once a year to a 55-year-old man who has been smoking for 30 years and smokes two packs a day, it can really bring him back from the hell of late-stage lung cancer.

Many people have no idea about the "incubation period". In fact, the lesions at this stage are like the mildew that has just grown on the corner of your house. It is just an inconspicuous little black spot at the beginning. It is gone after being wiped with a wet rag. When you find that the wall is soft and the mildew has spread to half of the wall, you have to pry the bricks, shovel the wall, and repaint. It is expensive and laborious, but it may not be able to restore it to its original state. Take high blood pressure as an example. The incubation period can be 5 to 10 years. Normally, you may only have an occasional headache or dizziness after staying up late. Most people don't take it seriously. By the time you get to the hospital for cerebral infarction or myocardial infarction, most of your blood vessels will have been blocked. Even if you are rescued, you will probably suffer from the sequelae of hemiplegia. At this time, it will be too late to treat it.

It is also interesting that many people have misunderstandings about screening. They choose the most expensive package, which includes a complete set of tumor markers, whole-body PET-CT, and cancer gene testing. It seems that the more money you spend, the more peace of mind you will have. We in the industry do our own screenings without looking at package prices. We first count our own risk factors on our fingers: Is there a family history of related diseases? Do you have high-risk habits such as smoking, drinking alcohol, or staying up late for a long time? Are you old enough to be in the high-risk range for the corresponding disease? My own grandmother died of breast cancer. When I reach the age of 40, I will definitely have a mammogram plus ultrasound every year. Now in my early 30s, a breast ultrasound every year is enough, so I don’t have to spend extra money.

When I was helping at the physical examination center last year, I met a 28-year-old young man who had no family history of gastric cancer and no Helicobacter pylori infection. He was eating regularly and had no stomach pain. He asked for a painless gastroscopy. He said that he was worried about getting gastric cancer after watching too many short videos. It took him a long time to persuade him to go back. This kind of excessive screening is caused by anxiety and is really unnecessary.

In the final analysis, no matter how controversial it is, the original intention of screening has never changed: it is not a tool to create health anxiety, nor is it a revenue-generating project. The core is to help you find the "invisible bombs" hidden in the incubation period in advance, dismantle them as soon as possible if they can be dismantled, and prepare in advance for those that cannot be dismantled. It is better than waiting for it to explode, right?