The relationship between disease screening and physical examination

Disease screening is a special branch of physical examination targeted at specific diseases and specific high-risk groups. Routine health examination is a universal basic health screening for the entire population. The two are complementary relationships between "casting a wide net" and "precision fishing". They can neither replace each other nor are they two completely separated types of health management projects.

Last week I met a 32-year-old girl at the physical examination center. She came with the company’s annual physical examination report, which showed two positive signs of Helicobacter pylori and long-term acid reflux symptoms. I reminded her that she had better go for an early screening for gastric cancer. She stared at me and asked me: Didn’t I just have a physical examination? Why do you still need to check? This should be a confusion for most people.

The general physical examination we often refer to is, to put it bluntly, an annual "health survey". It includes height and weight, blood and urine routine, liver and kidney function, and basic ultrasound chest X-ray. It touches on everything, but it doesn't dig too deep into anything. Take lung cancer as an example. In routine physical examinations, it is difficult to detect nodules less than 1cm in chest X-rays, let alone identify signs of early lung cancer. This is the core reason why many people have normal physical examinations every year, but are diagnosed with late-stage cancer as soon as they are detected.

The disease screening is different. It will not check your height and weight at all. All items focus on the early signs of a certain disease. For example, low-dose spiral CT for lung cancer can detect tiny nodules of more than 2 mm, and the detection rate for early-stage lung cancer can reach more than 90%; colonoscopy for colorectal cancer can even directly remove polyps that have not yet become cancerous, which is equivalent to nipping cancer in the cradle. But its shortcomings are also obvious: strong specificity means poor generalizability. If you, a 20-year-old girl who does not smoke and has no family history of lung cancer, undergoes low-dose CT, the risk of that little bit of radiation will be higher than your probability of getting lung cancer.

There has been debate in the industry over the priority of the two. Clinical doctors have seen too many patients with late-stage cancer and always feel that routine physical examinations are "useless". It is better to directly screen high-risk groups, which is more cost-effective. Experts in the public health field have made another calculation: if all people over 18 years old in the country are screened for lung cancer, the consumption of medical resources alone will be astronomical, not to mention the anxiety caused by a large number of false positive results and subsequent unnecessary punctures and biopsies, which will cause additional harm to healthy people. Both of these statements are actually correct, they just come from different angles.

I have been in the physical examination center for almost 8 years, and I have seen a lot of people in both extremes. There is a 45-year-old chain smoker who only undergoes routine physical examinations issued by the company every year. There is no problem with chest X-rays. Last year, he coughed for half a month and came for a check-up. The low-dose CT showed early-stage lung cancer. Fortunately, after the operation, he was fine. Now everyone says that screening is useful. There is also a 28-year-old young man who has no family history. He had no bad habits. I heard online that cancer screening was effective, so I decided to do a full set of PET-CT, which cost nearly 10,000 yuan. The result was a 3mm lung nodule. I was so scared that I couldn’t sleep well for half a month. I went to three hospitals. In the end, the doctors told him that he was fine and that he could just check back regularly. He was just scaring himself.

In fact, to use an inappropriate analogy, a routine physical examination is like the basic annual inspection you do for your car every year. You go through the lights, brakes, tires, and engine oil. If there are any minor problems, they will be flagged for you first. If you find that the brake pads are worn fast to the safety line, you will go for an in-depth inspection of the brake system. The in-depth inspection is a disease screening. You can't just never do annual inspections and just do a full set of racing-level in-depth inspections on the new car you just bought, right? It’s expensive and unnecessary.

As for how ordinary people should match, there is really no standard answer. For young people in their twenties who have no family history and have healthy lifestyles, a routine physical examination every year is enough. If thyroid nodules are found to be 4a in the routine physical examination, then they can go for special screening for thyroid cancer. If there is a family history of colorectal cancer, even if you are only 30 years old, don’t wait for routine physical examination to detect occult blood in the stool. Just go for regular colonoscopy, which is more reliable than anything else.

To put it bluntly, whether it is a routine physical examination or a disease screening, the essence is to install an early warning device for your health. No one is more noble than anyone else, and there is no unified standard answer. The one that suits you is the best. Oh, by the way, if you really don’t know what to choose, it’s much more useful to ask a reliable health manager with your physical examination reports for the past three years than to read random guides online.