Disease Description (Causes·Pathophysiology·Main Symptoms)
- Definition: Gastric carcinoid (gastric neuroendocrine tumor) is a tumor originating from neuroendocrine cells in the stomach, mainly enterochromaffin-like cells in the gastric mucosa and submucosa. It generally grows slowly but can metastasize.
- Pathophysiology and types (clinical significance):
- Type I: Associated with chronic atrophic gastritis; commonly develops due to reduced gastric acid and hypergastrinemia, and has a favorable prognosis.
- Type II: Associated with Zollinger–Ellison syndrome/MEN1.
- Type III: Sporadic, large, and invasive, with a relatively poor prognosis.
- Causes: The exact disease mechanism is unknown, but it may be associated with genetic mutations and underlying gastric diseases (atrophic gastritis and abnormalities of gastric acid or gastrin).
- Main symptoms:
- Often asymptomatic and discovered incidentally during endoscopy.
- When symptoms are present: abdominal pain, indigestion, vomiting, upper gastrointestinal bleeding (black stools·vomiting blood), and anemia.
- Rarely, carcinoid syndrome may occur due to substances secreted by the tumor (such as histamine), causing facial flushing, diarrhea, and increased intestinal motility (particularly in cases of liver metastasis).
Treatment Methods and Precautions
- Diagnostic tests (essential for establishing a treatment plan):
- Upper gastrointestinal endoscopy (including biopsy), endoscopic ultrasonography (EUS): Evaluation of size, depth of invasion, and nearby lymph nodes.
- Imaging tests: Abdominal CT·MRI, somatostatin receptor imaging (SSRT/gallium-PET, etc.) — evaluation for metastasis.
- Blood/urine markers: Blood chromogranin A, 24-hour urine 5-HIAA (when symptoms are present or metastasis is suspected), and gastrin testing (assessment of an association with hypergastrinemia).
- Treatment of localized lesions:
- Small, low-risk lesions confined to the mucosa or submucosa: Endoscopic resection (endoscopic submucosal dissection or resection) may be possible.
- When the tumor is large or invasion of the muscular layer or lymph node metastasis is suspected: Partial or total gastrectomy and extensive lymph node dissection.
- Advanced/metastatic lesions:
- Systemic chemotherapy (standardized regimens for neuroendocrine tumors vary according to the tumor’s differentiation and proliferation index).
- Symptom control and growth inhibition: Somatostatin analogues (octreotide, lanreotide) — relief of hormone-related symptoms and inhibition of the growth of some tumors.
- When somatostatin receptor-positive: PRRT (peptide receptor radionuclide therapy) may be considered.
- When liver metastasis is predominant: Hepatic resection, hepatic embolization, or local treatment (such as radiofrequency treatment) may be considered.
- Follow-up and surveillance:
- After treatment, monitor for recurrence and metastasis through regular endoscopy, imaging tests, and marker tests.
- Precautions and risk of complications:
- Carcinoid syndrome may worsen in cases of metastasis, particularly to the liver.
- Risk of postoperative complications (bleeding·infection·nutritional disorders) and perforation or bleeding from endoscopic treatment.
- There may be an associated risk of other tumors (gastric adenoma·lymphoma·breast·kidney, etc.) and endocrine diseases (MEN1, thyroid·adrenal diseases, etc.) — additional testing is recommended when necessary.
- Prevention: No specific preventive measures are known. Early detection and regular checkups are important.
Checklist Before an Outpatient Visit (Items to Bring and Medical History)
- Items to bring:
- A list of all medications currently being taken (including prescriptions and dosages) and supplements
- Previous test results (reports from previous endoscopy·biopsy·CT/MRI and blood test results) — bring the original documents if possible
- A record of when symptoms occur, how often they occur, and their severity (bleeding·abdominal pain·weight loss·diarrhea·flushing, etc.)
- Allergies·previous surgical history·family history (particularly relating to endocrine tumors or hereditary tumor syndromes (MEN))
- Information to organize in advance for the outpatient visit (examples of medical history questions):
- When symptoms first began and how they have changed
- Relationship to meals (whether they trigger pain or vomiting)
- Presence or absence of black stools·vomiting blood·anemia symptoms (such as dizziness)
- Whether medications (such as proton pump inhibitors) have been taken long term
Examples of General Questions to Ask the Doctor
- What type of lesion is this (Type I/II/III), and what is my prognosis?
- Do I need surgery, or would endoscopic resection be sufficient for my lesion?
- What additional tests (SSRT, EUS, gastrin/chromogranin testing) are needed in my case?
- What are the common side effects of treatment, and how are they managed?
- At what intervals will I be monitored for recurrence and metastasis after treatment?
Examples of Disease-Specific Questions
- What are the size and depth of invasion of my tumor (mucosal·submucosal·muscular layer involvement), and what treatment options are recommended based on these findings?
- If the somatostatin receptor imaging (SSRT/PET) is positive, should PRRT or somatostatin analogue treatment be considered?
(If necessary, bringing diagnostic materials and recent test results can help with more specific consultation and establishment of a treatment plan.)