The principle of early detection, early diagnosis and early treatment is a key strategy to improve the cure rate of cancer and improve the prognosis of patients. With the continuous advancement of cancer screening methods, more and more tumors can be detected at an early stage. "A single examination can screen out all cancer risks", "Cancer can be screened clinically with only a drop of blood", "X-rays can 'detect' early-stage lung cancer...... At present, there are many erroneous claims about tumor screening circulating on the Internet, and the reporter interviewed relevant experts about it.

Myth 1: A single test can screen out all cancer risks

Expert response: A comprehensive understanding of cancer risk requires a comprehensive application of multiple screening methods

There is a saying on the Internet that all cancer risks can be screened out with one comprehensive examination. In this regard, Wang Huaqing, a professor at Nankai University School of Medicine and director of the Cancer Diagnosis and Treatment Center of Tianjin People's Hospital, said: "Cancer is not a single disease, but a collective term for many different types of malignant tumors, involving multiple organs and tissues of the human body. "There are specific screening methods and biomarkers for each cancer, which means that there is no single test that can cover all cancer types.

For example, for example, breast cancer screening usually uses mammography (mammography); Colorectal cancer is screened using colonoscopy or fecal occult blood testing; Screening for prostate cancer may involve prostate-specific antigen testing; Screening for lung cancer relies on low-dose chest CT scans, etc. "The screening tools and strategies for each cancer are designed based on its biological characteristics and early manifestations." Wang Huaqing said.

A comprehensive understanding of a person's cancer risk requires a comprehensive application of a variety of screening methods, including but not limited to tumor marker testing, imaging tests, endoscopy, etc., and the tests should be tailored to specific factors such as the individual's age, gender, family history, and lifestyle.

Wang Huaqing suggested that the correct approach is to have doctors regularly develop personalized screening plans for individual cancer risk factors, in order to achieve early detection and early treatment of tumors.

Claim 2: Clinically, only a drop of blood is needed to screen for cancer

Expert response: At present, there are no mature related products put into application

In some movies, doctors can diagnose a variety of diseases, including cancer, with just a drop of blood. With the development of medical level, it is said that the technology of "blood drop cancer test" has now been applied in clinical practice.

Wang Huaqing said that the process of cancer screening and diagnosis is complex. At present, it is clinically difficult to screen for cancer with just a drop of blood.

Liquid biopsy is a non-invasive cancer detection method. It detects the presence of cancer by analyzing biomarkers in the blood, such as circulating tumor DNA (ctDNA), circulating tumor cells, or exosomes. "However, it is not easy to accurately screen for cancer from a single drop of blood." Wang Huaqing believes that firstly, the concentration of ctDNA released by tumors is extremely low and mixed with a large amount of normal DNA, which is extremely difficult to detect. Second, even if a ctDNA abnormality is detected, it does not necessarily mean that cancer is present, and this abnormality may also be caused by other factors; Finally, the number and variety of biomarkers released by different cancers vary greatly, and it is difficult for a single detection method to cover all cancer types.

It is reassuring to note that there have been significant advances in liquid biopsy technology in recent years. The research team has been able to detect very small amounts of ctDNA, which carry genetic variants specific to tumors. Through high-precision sequencing technology, scientists are working to improve the sensitivity and specificity of the assay, aiming to accurately identify cancer at an early stage when the signal is weak. "As the technology continues to mature, liquid biopsy is expected to be a powerful tool for cancer screening." Wang Huaqing said.

Claim 3: X-rays can "find" early lung cancer

Expert response: The tumor has grown to a certain extent before it can be visible on X-ray images

X-rays are often mentioned in early screening for lung cancer. It has been said that X-rays are effective in capturing lung cancer at an early stage.

Wang Huaqing said that X-ray examination has low sensitivity and specificity for early screening of lung cancer, especially for tumors with a diameter of less than 15 centimeters, and its detection rate is less than 0%. The tumor does not appear on X-ray images until it has grown to a certain extent. At this time, lung cancer has often progressed to the middle and advanced stages, and the difficulty of treatment has increased significantly, and the prognosis has also deteriorated significantly.

X-rays use X-rays through the body to produce two-dimensional images that help doctors see what is going on in the bones and certain soft tissues. However, X-ray imaging is affected by the overlapping of human tissues, smaller lung cancer lesions are easily obscured by the surrounding normal tissue structures, and early lung cancer may appear irregular or blurry shadows, so it is difficult for doctors to distinguish early lung cancer from benign lesions or normal variants through X-ray images. In addition, X-rays have limited resolution, which makes them even less useful for areas deep in the lungs or structurally complex.

"Compared to X-rays, low-dose spiral CT is the first choice for modern lung cancer screening, especially for high-risk groups such as long-term smokers and individuals with a family history of lung cancer." Wang Huaqing explained that CT scans can provide cross-sectional three-dimensional images, which can show the details of the lungs more clearly, and have a high detection rate even for small nodules. This makes it a safe and efficient early lung cancer screening tool. (Reporter Chen Xi)