Chest X-ray or CT for routine physical examination?

For healthy people under 40 years old, with no history of smoking, no family history of lung cancer, and no history of long-term exposure to dust/smoke/toxic gases, chest X-ray is completely sufficient.； For people over 40 years old who meet any of the above high-risk factors, low-dose spiral CT is preferred.

Last month, I helped my 37-year-old cousin choose a physical examination package. She struggled with the two options for almost half an hour. She said that the Internet said that a chest X-ray is "a piece of waste paper" and cannot detect cancer. It is useless and she insisted on spending an extra 300 yuan to upgrade to CT. I told her the situation: she didn’t smoke, no elders in her family had lung cancer, and she rarely even went into the kitchen while working in the office. So I just crossed out her CT option. It was really unreasonable.

There are actually two factions arguing about this issue on the Internet, and both of them make sense. On the one hand, those who advocate "CT for all" are mostly front-line thoracic surgeons and respiratory doctors. When I was rotating in the thoracic surgery department, my instructor said every day that I saw too many patients with normal chest X-rays and early-stage lung cancer on CT scan. The data from the National Cancer Center is also here: low-dose spiral. The detection rate of early-stage lung cancer by CT can reach over 90%, while traditional chest X-ray can only detect less than 10% of early-stage lung cancer. Many small nodules and ground-glass lesions are simply blind spots on the chest X-ray. By the time the mass is visible on the chest X-ray, they are already in the middle and late stages, and the best opportunity for treatment has been missed.

On the other side, those who oppose "universal CT" are mostly doctors in radiology departments and public health fields. They have another calculation: First of all, when it comes to radiation, the radiation dose of a chest X-ray is about 0.1mSv, which is almost equal to the natural radiation dose you take on a 10-hour long-distance flight. The radiation dose of low-dose spiral CT is about 1mSv. Although it is far lower than the annual safety threshold of 5mSv recommended by the International Commission on Radiation Protection, unnecessary radiation can be avoided as little as possible. Not to mention that many people are diagnosed with benign micro-nodules of 2 or 3 mm. Nothing is wrong at first, but they are anxious for more than half a year. They want to do a CT review every two months, but they consume more unnecessary radiation. This is a typical example of over-screening.

I saw two particularly impressive examples when I was helping to register in the radiology department: One was a 42-year-old taxi driver who had been driving and smoking for 20 years. Before, the physical examination at the work unit had always been chest X-rays, which showed normal results. Last year, he had his first low-dose CT scan and found an 8mm mixed ground-glass nodule in the right lung. The postoperative pathology was carcinoma in situ. He was cured after the operation and did not even need chemotherapy. The other is a 29-year-old girl who does not have any high-risk factors. She heard from a blogger that CT is more accurate. She has been doing CT for three consecutive years. Every time a small nodule of 2 mm is found, she cries and asks if it is cancerous. The doctor explains to her that it is an inflammatory nodule and does not need to be treated. She still comes for a check-up every six months. It is completely because she scares herself.

There is also a cost issue that is rarely mentioned. A chest X-ray can usually be done for a few dozen yuan, and the results can be obtained in 10 minutes. A low-dose CT costs at least two to three hundred yuan. If routine physical examinations are done every year, for young people without high-risk factors, the cost-effectiveness is indeed not high. Of course, if you have a history of pulmonary nodules, chronic obstructive pulmonary disease and other underlying diseases, no matter how old you are, you must follow your doctor's instructions for regular follow-up CT scans. This is another story.

I am 33 years old, have no history of smoking, and have no family history of lung cancer in my family. I always choose a chest X-ray for my annual physical examination. When I turn 40, no one needs to tell me, I will change the physical examination items to low-dose CT. After all, at an age when the risk is high, the money you should spend does have to be spent.

In fact, this issue has been debated for so many years. There is nothing wrong with the views of both sides. It is just a different stance: Clinicians have seen too many regrets of late-stage patients and hope to move the screening threshold as far forward as possible.； Public health and radiologists have seen too much anxiety about excessive medical treatment and hope that everyone will not do unnecessary examinations. You don’t have to listen to anyone and just believe everything. First, clarify your own situation and choose the answer that matches your risk level. This will be the answer that suits you best. After all, the essence of physical examination is to nip health risks in the bud at the lowest cost.