Blood tests can be an important reference for the diagnosis of gastric cancer, but they cannot be used as a criterion for a definitive diagnosis.
Some patients, especially those with a family history of gastric cancer, those who like to eat pickled foods, and those with bad lifestyle habits, suspect whether they have gastric cancer when they experience symptoms such as stomach discomfort, bloating, and acid reflux. After the patient visits the doctor, usually the doctor will choose some painless and non-invasive non-invasive tests at the first time, and blood test is naturally the first choice. The blood tests include routine tests and tests for tumor markers.
The results of routine blood tests give a general picture of the individual’s health status, and routine blood results in patients with tumors are often associated with some abnormalities. For example, some patients may have more severe anemia on their blood tests during a physical exam, which is an abnormal sign. The doctor will examine further around the possible cause of the anemia, and the combination of tumor markers, imaging, and pathology biopsy may eventually lead to a diagnosis of gastric cancer. In other words, routine blood tests may reveal some signs suggestive of gastric cancer.
On the other hand, we need to focus on the tumor markers associated with gastric cancer, which include: carcinoembryonic antigen (CEA), glycoconjugate antigen 19-9 (CA19-9), glycoconjugate antigen 125 (CA125), glycoconjugate antigen 72-4 (CA72-4), serum alpha-fetoprotein (AFP), and so on. It should be noted that the specificity (that is, the chance that the index is not misdiagnosed when diagnosing the disease; high specificity means low misdiagnosis rate when diagnosing based on the index) and sensitivity (that is, the chance that the index is not missed when diagnosing the disease; high sensitivity means low missed diagnosis rate when diagnosing based on the index) of the commonly used tumor markers for gastric cancer in clinical practice are not very satisfactory, therefore, serum tumor markers are not ideal for diagnosing gastric cancer. Therefore, the role of serum tumor markers in confirming the diagnosis of gastric cancer is limited to the suggestive role. Therefore, the role of serum tumor markers in confirming the diagnosis of gastric cancer is only suggestive. If a definite diagnosis is needed, multiple tests (imaging, etc.) are required, and the final diagnosis is made by biopsy pathology (the gold standard). (Contributed by Jianhua Wu, Department of Gastrointestinal Oncology, The First Hospital of China Medical University)