The Chinese standard for the diagnosis and treatment of common malignancies requires that gastroscopy should be the first option once gastric cancer is clinically suspected. Many people undergo gastroscopy for the purpose of screening for gastric cancer.
However, gastroscopy is not a panacea for the diagnosis of gastric cancer, and it remains unclear what should be done for those who have a negative initial test. In a UK study, 3,672 people who were not detected at the initial gastroscopy were diagnosed with gastric cancer in 32 cases at the subsequent 3-year follow-up.
So, a negative endoscopy does not completely rule out gastric cancer.
Why is there a false negative on endoscopy?
A false negative is when a lesion is actually present but not detected on examination. In some types of gastric cancer, especially early gastric cancer, the lesions are very small, and some mucinous adenocarcinoma and invasive cell carcinoma, which are mainly submucosal infiltrates, are often intact, and the cancer cells mainly infiltrate along the submucosal layer, so the above lesions are not easily detected by gastroscopy and thus missed; some lesions at the bottom of the stomach are often covered with mucus, and the proximity of the lesions to the mirror body makes observation and sampling more difficult. In some small gastric cancer lesions (less than 1 cm), the mucosa of the lesion will pseudo-heal after the patient takes oral omeprazole (Omprazole), but the cancer cells are still multiplying rapidly and can cause metastasis.
In addition, gastroscopy does not directly visualize H. pylori and cannot rule out the presence of H. pylori, which is associated with the development of gastric cancer. Experts believe that H. pylori should be routinely examined during gastroscopy, where 1 to 2 pieces of gastric sinus mucosal tissue are clamped under the gastroscope and placed in a solution containing urea, and if it turns red after a few minutes, it proves the presence of H. pylori, a method known as the rapid urease test; doctors can also send the biopsied gastric mucosa to the pathology department for sectioning and examination, and directly observe the presence of H. pylori under the microscope through staining; non-gastroscopic The presence of H. pylori can also be determined by non-gastroscopic methods (e.g., breath tests and blood tests).
Does a negative endoscopy require further testing or follow-up?
- If the subject only has a normal physical examination, no recent symptoms such as loss of appetite, upper abdominal discomfort or fullness, nausea and belching, vomiting of blood and black stools, or vague stomach pain, and no family history of gastric cancer, further examination may not be required and regular physical examination for follow-up gastroscopy is sufficient.
- If the subject is at high risk for clinically suspected gastric cancer or has significant gastric disease such as gastric mucosal atrophy, the doctor will usually recommend further ultrasound endoscopy to clarify the diagnosis.
- If the physician believes that negative results in some patients may be due to superficial or inappropriate sampling of the gastroscopic biopsy (failure to reach the cancerous parenchyma), he or she will usually recommend regular close follow-up and repeat gastroscopy within 3 months to clarify the diagnosis. (Contributed by Yu Miao, Department of Gastrointestinal Oncology, The First Hospital of China Medical University)