Duodenal ulcer

Disease Description (Causes and Symptoms)

• Definition: Small intestinal cancer is a malignant tumor arising in the small intestine (duodenum, jejunum, or ileum). It is very rare and accounts for approximately 0.5% of all cancers. Tumor types include adenocarcinoma, neuroendocrine tumors (carcinoid/NET), malignant lymphoma, sarcoma (including GIST), and lesions metastatic from other organs.
• Pathophysiology summary: The mechanism of development differs according to the cell of origin, such as epithelial cells, lymphocytes, stromal cells, and smooth muscle cells. Adenocarcinoma develops through dysplastic proliferation of the mucosal epithelium followed by invasion and lymph node metastasis; NETs cause symptoms through secretion of serotonin and other substances by neuroendocrine cells; GISTs are associated with KIT/PDGFRA mutations in cells resembling the interstitial cells of Cajal.
• Main causes and risk factors: Consumption of high-fat foods, red meat, and salted or smoked foods; smoking and radiation exposure; certain genetic syndromes (familial adenomatous polyposis, Li-Fraumeni syndrome, neurofibromatosis, Peutz-Jeghers syndrome, etc.); inflammatory bowel disease (Crohn’s disease); celiac disease; and exposure to estrogen/anabolic steroids or pesticides. The incidence increases in men and older adults.
• Main symptoms: Most cases are nonspecific or asymptomatic in the early stages. As the disease progresses, symptoms may include abdominal pain, weight loss, loss of appetite, intestinal obstruction (vomiting and abdominal distension), gastrointestinal bleeding (anemia and bloody stool), abdominal discomfort and bloating, a localized mass, jaundice in rare cases (lesions in the ampulla of the duodenum), and intestinal perforation. In cases of carcinoid tumors, facial or chest flushing, watery diarrhea, and asthma-like symptoms (carcinoid syndrome) may occur.

Treatment Methods

• Principles: Treatment varies according to the pathological type and stage (localized, lymph node, or distant metastasis). Overall, surgical resection is the main treatment.
• Surgery
  • Adenocarcinoma: Pancreaticoduodenectomy (Whipple procedure) may be considered for lesions in the proximal duodenum. For lesions in the distal duodenum, jejunum, or ileum, segmental intestinal resection including the lesion and removal of the surrounding lymph nodes are performed as radical resection. Partial resection may be performed to relieve intestinal obstruction or bleeding.
  • NET (carcinoid tumor): Partial or extensive resection and lymph node removal are determined according to tumor size, multiplicity, and the presence or absence of lymph node metastasis. If the tumor is <1 cm and has not metastasized, limited resection is often sufficient.
  • Malignant lymphoma: Surgical resection may be necessary, but combining chemotherapy and radiation therapy can improve the prognosis.
  • Sarcoma/GIST: Complete resection is the priority. Lymph node metastasis is rare, so lymph node dissection is generally not necessary.
• Drug Therapy and Radiation
  • Adenocarcinoma: The effectiveness of standardized chemotherapy is limited. Individualized anticancer therapy is used for metastatic disease or as adjuvant therapy.
  • NET: Symptom control (anti-serotonin agents, etc.), palliative treatment, and selectively, targeted therapy.
  • GIST: If a KIT or PDGFRA mutation is identified, imatinib (Imatinib) is effective for unresectable or metastatic disease or as adjuvant treatment.
  • Lymphoma: Combining chemotherapy and radiation therapy is important.
• Lifestyle Management and Precautions
  • Follow-up after surgery (including imaging, endoscopy, and tumor markers) and nutritional management are necessary. Malabsorption, diarrhea, and weight loss may occur after intestinal resection, so dietary adjustment and supplementation may be needed.
  • Immediate medical attention is necessary if emergencies such as bleeding, obstruction, or perforation occur.
  • Monitoring for treatment-related medication side effects (such as leukopenia and abnormal liver function) and surgical complications (such as bleeding, infection, and adhesions) is important.

Checklist Before an Outpatient Visit (Including Example Questions)

• What to prepare
  • A list of current medications (including prescriptions, OTC medications, and supplements) and any recent medication changes
  • Past medical history (surgeries, cancer history, and hereditary diseases) and family history (colorectal cancer, polyps, etc.)
  • Previous test results (blood tests, CT/MRI, endoscopy and pathology reports, capsule endoscopy images, etc.) prepared as printouts or in the electronic medical record
  • Symptom records: onset, frequency, and severity (abdominal pain, bleeding, weight changes, changes in bowel movements, fever, etc.) and whether there has been acute worsening
  • Notes on recent weight and dietary changes
• Information to provide during the outpatient visit
  • The timing and characteristics of symptoms (obstructive symptoms, bleeding, etc.) and the amount of recent weight change
  • Whether there is a history of intestinal diseases (Crohn’s disease, celiac disease, etc.) or hereditary diseases
• Examples of questions to prepare in advance for the outpatient visit
  • "Could you explain the results of the recent tests (CT/endoscopy) while reviewing them with me?"
  • "What additional tests are needed (capsule endoscopy, 24-hour urine 5-HIAA, genetic testing, etc.)?"

Examples of General Questions to Ask the Doctor

• What is the histologic type of this lesion (adenocarcinoma/NET/GIST/lymphoma, etc.) and what is its stage? Is the treatment goal a cure?
• Can it be cured with surgery? What is the extent of surgery and what complications are expected?
• What are the expected effects and side effects of the proposed chemotherapy or targeted therapy?
• What will the follow-up testing schedule and methods be? What points require particular attention regarding lifestyle and diet?

Examples of Disease-Specific Questions

• (If the suspected pathology is a carcinoid tumor) Is a 24-hour urine 5-HIAA test necessary? If symptoms of carcinoid syndrome (flushing, diarrhea, asthma, etc.) are present, would drug treatment (e.g., octreotide) be appropriate?
• (If GIST is suspected or confirmed) Will KIT/PDGFRA genetic mutation testing be performed? In what situations is imatinib treatment recommended, and what is the expected treatment duration?

(Note: This summary is intended to support diagnosis and treatment decisions, and the care plan may vary depending on each patient’s medical history and test results.)