Stomach cancer, also known as gastric cancer, begins in the cells lining the stomach. A common question arises regarding the role of blood tests in its detection. While blood tests are a valuable part of the overall diagnostic process, they cannot definitively diagnose stomach cancer on their own. Instead, these tests provide supportive information that guides further investigation.
What Blood Tests Can Reveal
Blood tests can offer clues about a person’s general health and potential abnormalities, indicating the need for more specific examinations. A complete blood count (CBC) often checks for anemia, a low red blood cell count that can result from chronic internal bleeding caused by a stomach tumor. Liver function tests (LFTs) assess liver health; elevated enzyme levels might suggest cancer has spread to the liver.
Specific tumor markers, such as Carcinoembryonic Antigen (CEA) and Carbohydrate Antigen 19-9 (CA 19-9), can also be measured in the blood. These proteins are produced by cancer cells or by the body in response to cancer. While their levels may be higher in the presence of a stomach tumor, they are not used for initial diagnosis. Instead, tumor markers primarily monitor a patient’s response to treatment or detect cancer recurrence.
Why Blood Tests Aren’t Definitive
Despite the information they provide, blood tests alone are not sufficient for a definitive stomach cancer diagnosis due to several limitations. Tumor markers like CEA and CA 19-9 lack specificity; their levels can be elevated in various non-cancerous conditions, including inflammation, benign digestive disorders, liver dysfunction, or other cancers. This can lead to false positive results, where an elevated marker level does not indicate stomach cancer.
Blood tests also have sensitivity limitations, particularly in early stomach cancer. Not all stomach cancers produce elevated tumor markers, and levels may not rise until the disease is more advanced. This can result in false negative findings, where a person has stomach cancer but their blood test results appear normal. Furthermore, blood tests cannot provide visual information about a tumor’s presence, size, or exact location, which is essential for accurate diagnosis and staging.
Definitive Diagnostic Methods
When stomach cancer is suspected, more direct and definitive diagnostic methods are necessary to confirm its presence and determine its characteristics. Endoscopy, specifically an upper gastrointestinal (GI) endoscopy or gastroscopy, is the primary diagnostic tool. During this procedure, a doctor inserts a thin, flexible tube with a camera down the throat to visualize the inner lining of the esophagus, stomach, and the first part of the small intestine.
If suspicious areas, such as abnormal growths or ulcers, are identified during endoscopy, a biopsy is performed. This involves using small instruments passed through the endoscope to collect tissue samples from the suspicious area. A pathologist then examines these samples under a microscope to confirm cancer cells and determine the specific type of cancer. The biopsy is considered the gold standard for diagnosing stomach cancer. Imaging tests, such as CT and PET scans, are used after diagnosis to determine cancer extent and spread, aiding in staging.
When to Seek Medical Advice
Understanding the signs and symptoms that may indicate stomach cancer is important for seeking timely medical attention. Common symptoms include persistent indigestion or heartburn, unexplained weight loss, abdominal pain or discomfort, nausea, and vomiting. Individuals might also experience difficulty swallowing or feel full quickly after eating a small amount of food.
Blood in stool or a low red blood cell count indicating anemia can also be concerning symptoms warranting medical evaluation. These symptoms can also be caused by less serious conditions. Therefore, if any persistent or concerning symptoms arise, consulting a healthcare professional for proper evaluation and diagnosis is recommended rather than attempting self-diagnosis.