Can normal tumor markers rule out cancer

Normal tumor markers usually cannot completely rule out cancer. Tumor biomarker detection is an auxiliary diagnostic tool, but there is a possibility of false negatives, which requires comprehensive evaluation based on imaging, pathological examination, and other factors.

Tumor markers are substances produced by tumor cells or the body in response to tumors, and their elevated levels may indicate the presence of tumors, but their specificity is limited. Some early-stage cancers or low secretion tumors may not cause abnormal biomarkers. For example, prostate-specific antigen may be normal in early prostate cancer, while carbohydrate antigen 125 has a sensitivity of only about 50% in early ovarian cancer. Certain benign conditions such as inflammation and infection may also lead to mild elevation of biomarkers, resulting in false positives. Commonly used clinical biomarkers include alpha fetoprotein, carcinoembryonic antigen, carbohydrate antigen series, etc., but the diagnostic value of a single indicator is limited. In rare cases, there are cases where tumor markers remain negative but cancer is ultimately diagnosed. This type of situation is more common in malignant tumors with small tumor volume, slow growth, or special pathological types. Neuroendocrine tumors may only secrete trace markers, while some renal cell carcinomas produce almost no specific markers. Some patients with hereditary tumor syndrome may not show any abnormalities in biomarkers during early screening. In addition, technical factors such as differences in sensitivity of detection methods and improper specimen handling may also affect the accuracy of the results.

It is recommended that high-risk people conduct targeted cancer screening regularly. For example, long-term smokers need low-dose CT to screen lung cancer, and hepatitis B virus carriers should monitor alpha fetoprotein combined with liver ultrasound. Individuals aged 40 and above may consider undergoing examinations such as gastroscopy and colonoscopy. If symptoms such as unexplained weight loss, persistent pain, or abnormal bleeding occur, even if the biomarkers are normal, medical attention should be sought promptly. A healthy lifestyle such as quitting smoking and limiting alcohol consumption, having a balanced diet, and regular exercise can help reduce the risk of cancer.