The objective of this prospective, observational, controlled clinical study is to use magnetically-controlled capsule gastroscopy for postoperative assessment in elderly patients and patients with underlying diseases, to evaluate its clinical efficacy and safety.

Gastric cancer is the most common digestive tract malignancy in China, which severely impacts human health and quality of life. Currently, surgery is the main treatment for gastric cancer. Since the surgery removes part or all of the stomach for malignant tumor, various postoperative complications inevitably occur. The occurrence of postoperative complications is detrimental to the prognosis of patients. Therefore, regular follow-up after surgery is necessary to closely monitor for upper gastrointestinal symptoms and periodically examine intragastric lesions in order to make timely diagnosis and treatment, and improve quality of life. Standard endoscopy procedures often cause discomfort and poor compliance in elderly patients. Also, for patients with severe respiratory diseases, severe cardiocerebral vascular diseases, the risks of anesthesia are extremely high. Magnetic-controlled capsule gastroscopy has the advantages of being completely painless, convenient, highly accurate in diagnosis, and well-accepted by patients. It is more suitable for postoperative assessment in elderly patients and patients with underlying diseases.

Inclusion Criteria:

• Planned to undergo magnetic-controlled capsule gastroscopy or conventional endoscopy, and have undergone surgery for gastric malignant tumors (including surgical resection and ESD), elderly patients (older than 65 years) or patients with underlying diseases (cardiovascular, respiratory, hemorrhagic diseases, etc.);
• Agree to participate in this clinical trial and sign the informed consent form.

Exclusion Criteria:

• No surgical conditions or refuses abdominal surgery (Once the capsule is stuck it cannot be removed surgically);
• Cardiac pacemakers (except MRI-compatible ones);
• Electronic implants or metal foreign bodies;
• Pregnant women;
• Known or suspected GI obstruction, stenosis, fistula;
• Dysphagia.

Elderly patients (older than 65 years) and patients with underlying diseases (cardiovascular, respiratory, hemorrhagic diseases, etc.) who underwent surgery for gastric malignant tumors (including surgical resection and ESD).