The overall 5-year survival rate for gastric cancer is not ideal, and one means of changing the status quo is early detection, early diagnosis, and early treatment. Today, with the rapid development of imaging, blood tests are still an essential and important tool. What are the commonly used serum tumor markers for gastric cancer and what do they suggest for gastric cancer diagnosis? We will learn more about them.
What are the commonly used serum tumor markers for gastric cancer?
What are the common serum tumor markers for gastric cancer?
Serum tumor markers for gastric cancer include: carcinoembryonic antigen (CEA), glycoantigen 19-9 (CA19-9), glycoantigen 125 (CA125), glycoantigen 72-4 (CA72-4), serum alpha-fetoprotein (AFP), and more.
Carcinoembryonic antigen (CEA)
CEA, a broad-spectrum tumor marker, is elevated in a variety of tumors, including gastrointestinal tumors, breast cancer, lung cancer, etc. CEA has a relatively high sensitivity in gastrointestinal tumors, meaning that patients with elevated CEA are more likely to have a gastrointestinal tumor.
The rate of CEA positivity and elevated levels are also more related to things like tumor staging and prognosis. In other words, if a patient with gastric cancer has a very high preoperative CEA level, it is likely that the patient will have a more advanced stage of disease, such as having lymph node metastases, tumors that have penetrated the stomach wall to reach the outermost plasma layer, and high malignancy, and the patient may have less than optimal survival expectations after surgery.
CEA can also be used as an indicator for outcome evaluation. Usually, the CEA level in cancer patients decreases significantly after surgery, and if the CEA is elevated again on review, it often indicates tumor recurrence. In some patients receiving combination therapy such as chemotherapy, CEA can also be used as an indicator of efficacy, and a decrease in CEA levels to a certain range or even a complete return to normal for a certain period of time after treatment can be used as an indicator of the effectiveness of this treatment.
Glucose antigen 19-9 (CA19-9)
CA19-9 is also a tumor marker commonly used in digestive tumors, especially in pancreatic cancer, and when combined with other tumor markers such as CEA, CA19-9 can improve the sensitivity of diagnosing gastric cancer. The results of this study are summarized below.
Glycan antigen 72-4 (CA72-4)
CA72-4 is by far the most specific tumor marker for the diagnosis of gastric cancer. That is, if CA72-4 is not significantly elevated, the subject is less likely to have gastric cancer.
AFP (alpha-fetoprotein)
AFP originally appears in human embryos, and its expression level decreases after birth and is very low in adult blood. Serum AFP levels are significantly elevated in patients presenting with germ cell tumors (teratomas, testicular cancer, ovarian malignancies, etc.) or hepatocellular tumors. AFP levels are also elevated in some specific types of gastric cancer (e.g., gastrohepatic-like adenocarcinoma), so AFP is suggestive for the diagnosis of specific types of gastric cancer.
Glycan antigen 125 (CA125)
CA125 is the most commonly used tumor marker for ovarian cancer, however, it is also a good diagnostic aid in breast, pancreatic, and digestive cancers, and has a high sensitivity in digestive tumors, especially when tumors invade the peritoneum and metastasize, and CA125 levels tend to be elevated. In other words, if a patient has elevated CA125 levels, laparoscopy should be considered to determine if peritoneal metastases are present.
Summary: Tumor markers are better together than alone in diagnosing gastric cancer
How useful are tumor markers for the diagnosis of gastric cancer? For example, in a group of patients suspected of having a tumor, a tumor marker with high sensitivity can be used to screen for tumors, trying not to miss anyone who might have a tumor, but some of these people will be misdiagnosed as having a tumor; then a tumor marker with high specificity can be used to screen out those who are misdiagnosed, and eventually the patients who are most likely to have a tumor are identified.
An individual marker that increases the sensitivity of its diagnosis may have less specificity; in other words, reducing missed diagnoses necessarily increases misdiagnosis. In clinical practice, oncologists are always looking for markers with ideal sensitivity and specificity for gastric cancer diagnosis, however, the fish and the bear’s paw often cannot be combined, and the combination of multiple tumor markers will yield the desired results. (Contributed by Jianhua Wu, Department of Gastrointestinal Oncology, The First Hospital of China Medical University)