Discovering elevated tumor markers does not necessarily mean that cancer has already developed. At present, the primary reasons that may lead to an increase in tumor markers include the following aspects:

Firstly, individuals in the preclinical stage of cancer, meaning the tumor already exists but cannot be detected through currently available diagnostic methods. In such cases of preclinical cancer patients, their tumor markers may also be elevated. Similarly, benign conditions such as endometriosis, inflammation, polyps, benign tumors, and skin diseases may also lead to elevated tumor markers.

Second, taking Western medicine, traditional Chinese medicine, or health supplements may also cause an elevation in tumor markers. Close contact with pets or patients with renal insufficiency may also lead to an increase in tumor markers.

Third, there are cases of unexplained elevation in tumor markers. This means that an increase in tumor markers is detected during a physical examination, but after a period of follow-up, the markers return to normal, and clinical examinations fail to identify the cause of the elevation. This is referred to as an unexplained elevation in tumor markers.

Fourth, another situation involves systematic errors in testing. This occurs when many individuals tested at the same time show elevated levels of the same marker. When testing is conducted at another facility or the testing method is adjusted, the marker levels return to normal. In such cases, the elevation is due to errors in the testing process. Therefore, if an elevation in tumor markers is detected, it is generally advisable to retest.

First, individuals with mild elevations in tumor markers, defined as values no more than 2–3 times the upper limit of normal, should undergo a retest of the same markers about a month later. Additional markers may also be tested as appropriate. During this period, it is recommended to adjust lifestyle habits, such as quitting smoking, limiting alcohol consumption, adjusting diet, and improving sleep. Additionally, there may be a delay between the detection of abnormal tumor markers and the diagnosis of a tumor. Therefore, after confirming abnormal tumor markers through retesting, a comprehensive examination and long-term follow-up should be conducted.