Stomach cancer

1) Disease Description (Causes and Symptoms)

• Summary of definition: A malignant tumor arising from the gastric mucosa; most cases (approximately 98%) are gastric adenocarcinomas. It begins in the mucosa and gradually invades the submucosa, muscular layer, and serosa, and may spread to the liver, lungs, bones, and other sites through lymph-node or hematogenous metastasis.
• Major causes and pathophysiology:
  • Precancerous lesions such as chronic atrophic gastritis, intestinal metaplasia, and dysplasia increase the risk of gastric cancer. (Progression to gastric cancer may take several decades.)
  • Helicobacter pylori infection is known to increase the risk of gastric cancer by 2.8–6 times. However, depending on clinical data, some cases in which only H. pylori is incidentally found during endoscopy may be managed without immediate treatment (consultation with a specialist is necessary).
  • Dietary factors: Consumption of nitrate-based preservatives, salted or smoked foods, and high-salt foods, as well as smoking and alcohol consumption, increases the risk.
  • A history of surgery (gastrointestinal anastomosis), genetic predisposition (family history and hereditary syndromes), and environmental exposure (such as asbestos) are also associated.
• Major symptoms:
  • Early stage: Nonspecific symptoms such as indigestion, upper-abdominal discomfort or pain, early satiety, and loss of appetite (similar to gastritis or an ulcer).
  • As the disease progresses: Weight loss, hematemesis or melena (gastrointestinal bleeding), symptoms of anemia (fatigue and dizziness), vomiting, abdominal distension (ascites), or a palpable abdominal mass.

2) Treatment Methods

• Treatment principles after diagnosis and staging: Depending on the stage (whether the disease is localized or metastatic), treatment is classified as curative resection, endoscopic treatment, adjuvant therapy (preoperative or postoperative chemotherapy), and anticancer, targeted, or immunotherapy.
• Localized or early lesions
  • Endoscopic treatment: Endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) is the standard treatment. If the criteria for application are met (for example, confinement to the mucosa, tumor size, and presence or absence of ulceration), it may be performed instead of open or laparoscopic surgery. It is usually performed under sedation (sedated endoscopy) or anesthesia.
  • Surgical resection: Partial gastrectomy (radical surgery) or total gastrectomy + lymph-node dissection (depending on the location and extent) — with curative intent for early or locally advanced gastric cancer.
• Advanced or metastatic gastric cancer
  • Systemic chemotherapy (anticancer treatment): Used when surgery is not possible or as adjuvant therapy. Standard regimens include fluorouracil-based combination therapy (such as FOLFOX and XELOX) and combination regimens such as FLOT (docetaxel, oxaliplatin, 5-FU, leucovorin, etc.) (determined according to the stage and the patient’s condition).
  • Targeted therapy: Trastuzumab (trastuzumab) in combination therapy is effective in HER2-positive advanced gastric cancer. Anti-angiogenic targeted agents (such as ramucirumab) may be used for advanced or recurrent gastric cancer.
  • Immunotherapy: PD‑1/PD‑L1 inhibitors (such as pembrolizumab) may be considered according to PD-L1 expression or specific biomarkers (depending on the indication and test results).
  • Radiation therapy: May be used to relieve localized symptoms (such as bleeding or pain) or to control the disease.
• Supportive care and lifestyle management
  • Symptom-relieving treatment, including transfusion and nutritional management for bleeding or anemia, pain control (narcotic analgesics if necessary), and drainage for ascites.
  • After surgery: Eating small meals frequently to relieve digestive discomfort (dumping syndrome), and monitoring and supplementing vitamin B12 deficiency (especially after total gastrectomy), among other measures.
• Latest and important considerations
  • Confirm the diagnosis through endoscopy and biopsy, and determine the stage through computed tomography (CT) and other tests before surgery. Results of molecular marker tests such as HER2, MSI, and PD‑L1 affect decisions regarding anticancer, targeted, and immunotherapy.

3) Checkpoints Before an Outpatient Visit (Including Recommended Items to Bring and Example Questions)

• Recommended items to bring
  • A list of all medications currently being taken (including prescriptions, OTC medications, and herbal medicines) and the most recent dosages
  • Records of past medical conditions and surgeries (especially stomach or abdominal surgery)
  • Family history (family history of cancers such as gastric or colorectal cancer)
  • Copies of recent test results, if available (blood tests, upper gastrointestinal endoscopy reports, CT scans, etc.)
  • A record of changes in symptoms (when symptoms began, frequency, relationship to meals, weight changes, stool color, etc.)
• Precautions before examinations and procedures
  • Fasting before upper gastrointestinal endoscopy (usually fasting for 6–8 hours before the examination). Follow the treating physician’s instructions regarding certain medications, such as blood-pressure medication.
  • Kidney function (creatinine) must be checked before CT with contrast.
  • If taking anticoagulants (such as warfarin or NOACs), consult the doctor in advance about whether they should be discontinued.
• Key information to provide to the doctor during the outpatient visit
  • Recent weight changes (how many kilograms and over what period)
  • Whether bleeding symptoms such as melena, hematochezia, or hematemesis are present
  • Symptoms after eating (vomiting, reflux, or early satiety)
  • The location, intensity, and type of pain and its impact on daily life

4) Examples of General Questions to Ask the Doctor

• “What is my stage, and what is my prognosis?”
• “What treatment options do you recommend, and what are the benefits and side effects of each?”
• “Do I need surgery? Is endoscopic treatment (ESD) an option in my case?”
• “Which of anticancer treatment, targeted therapy, and immunotherapy can I receive?”
• “What should I be careful about in my daily life and diet after surgery or anticancer treatment?”
• “How can nutritional management or vitamin deficiencies (especially B12 deficiency) caused by treatment be prevented and managed?”

5) Examples of Disease-Specific Questions

• “Were my gastric cancer tissue samples tested for HER2, PD‑L1, and MSI? Depending on the results, would targeted therapy or immunotherapy be possible?”
• “I was told that intestinal metaplasia or dysplasia was present on endoscopy (or biopsy). What follow-up screening schedule and additional treatment recommendations should I follow?”