The following is the text version:
Many physical examination items now include the measurement of various tumor markers in the blood, such as “carcinoembryonic antigen”, “alpha-fetoprotein”, “sugar antigen” and so on. Is this worth much?
Before Pineapple answers this question, please go to Baidu to search for the keywords “cancer, physical examination, false alarm”. I tried it and found nearly 100,000 web pages! Many of these false alarms come from the detection of tumor markers, which actually answers the question just now. (Extended reading: Why are there so many “false alarms” in screening?)
The primary value of tumor markers is in the monitoring of cancer patients, not in healthy individuals. Markers can monitor cancer growth and recurrence during or after a patient’s treatment. Using “tumor markers” alone in the physical examination of healthy people cannot really be used to judge whether you have cancer. It must be used in conjunction with other examinations for reference.
None of the “tumor markers” are specific to cancer, so there will be false positives: benign tumors, embryonic tissues, and even normal tissues may express these markers, This results in “false positives”.
Inflammation, infection, and even skin diseases may lead to the rise of “tumor markers”. If an examination is done at this time, it may frighten people to death. This is why many people have cancer prevention examinations. The reason for the false alarm. In fact, more than 95% of tumor marker positive results are false positives if used in general public health examinations.
There is also no “tumor marker” suitable for all cancers, so there will be false negatives: for example, the marker for breast cancer is not available for lung cancer, and the marker for lung cancer is rectal There is no cancer. What’s more, there are hundreds of cancer types, and the vast majority of cancers have no markers to detect. Scientists have yet to discover a broad spectrum of “tumor markers.”
Any “tumor marker” in the current physical examination, even if it is effective, is only meaningful for a certain type of cancer, and even if it is negative, it can at most rule out the possibility of a certain type of cancer , which results in a large number of “false negatives”: tumor marker screeningnegative, but cancer is still possible.
For breast cancer patients, it is very valuable to check breast cancer markers after treatment to know if the cancer has recurred. But for the general public, if you already have other cancers at the time of physical examination but do not know it, it is impossible to detect whether there is lung cancer, rectal cancer, or stomach cancer only by detecting the markers of breast cancer. If only a few negative results are used to rule out cancer, It will only delay the disease.
Because of the high “false positives” and “false negatives”, tumor markers can neither rule out nor confirm the occurrence of cancer. The significance of screening and physical examination for ordinary people is not as good as that of being used for screening. As big as the inspector had hoped.
What should I do if the physical examination reveals that the tumor markers are a little higher? It is usually recommended to check again in a few months. If it does not continue to increase, or even returns to normal, there is no need to worry. If it continues to increase, it is really risky and needs to be further checked. For tumor markers, the trend is more important than the value measured once!
Salute to life!
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