Metastatic cancer

Disease Description (Causes and Symptoms)

• Definition summary: Metastasis is the process in which cancer cells that have detached from the primary tumor (cancer) travel through the lymphatic or blood vessels and settle in a distant organ or tissue, forming a new tumor. It may be suspected clinically through imaging and blood tests, but confirmation requires a biopsy of the area suspected to contain metastasis.
• Causes and pathophysiology (brief summary): Cancer cells invade surrounding tissue → enter the lymphatic or blood vessels (intravasation) → travel along the bloodstream or lymphatic flow → become trapped in capillaries of a specific organ, pass through the vessel wall into the tissue, and then settle and proliferate (colonization). The immune response may suppress the spread of some cancer cells, but some evade the immune system and spread. Metastasis commonly occurs in organs with abundant blood vessels, such as the liver, lungs, brain, and bones. (Clinical note: A 1-cm lesion may contain approximately 10^9 cells.)
• Main symptoms:
  • Local symptoms: Palpable lump, pain in the affected area, swelling at the tumor site
  • Examples of organ-specific symptoms: Liver metastasis → abdominal pain, jaundice, abnormal liver function; lung metastasis → cough, shortness of breath, hemoptysis; bone metastasis → localized pain, pathological fracture, symptoms of hypercalcemia; brain metastasis → headache, nausea, neurological deficits, seizures
  • Systemic symptoms: Weight loss, fatigue, fever (cancer-related inflammation/infection), anemia, etc.

Treatment Methods

• Treatment principles: Treatment is personalized based on the type of primary cancer, location and number of metastases (single vs. multiple), the patient's general condition (performance status), and molecular targets (gene mutations, PD-L1, etc.). Treatment goals are divided into cure (rare cases), prolonging life, and symptom relief (improving quality of life).
• Systemic treatment
  • Chemotherapy (anticancer drugs) — still a widely used standard treatment
  • Targeted therapy — treatment based on molecular targets in the tumor (e.g., TKI for specific gene mutations)
  • Immunotherapy (immune checkpoint inhibitors) — targets such as PD-1/PD-L1
  • Hormone therapy — used for hormone-sensitive cancers (e.g., breast cancer, prostate cancer)
• Local and site-directed treatment for metastases
  • Surgery: When a single metastasis or limited metastases can be resected (e.g., resection of liver or lung metastases)
  • Radiation therapy: Local control (symptom relief, pain reduction); specialized treatment for central nervous system metastases (SRS/SBRT, whole-brain radiation)
  • Local procedures: Radiofrequency ablation (RFA), transarterial chemoembolization (TACE; for liver metastases/liver cancer), cryotherapy, etc.
• Palliative and supportive care
  • Pain management (analgesics, radiation, etc.), bone-strengthening agents (anti-resorptive agents, denosumab), blood transfusions, nutritional management, psychosocial support, and hospice/palliative care
• Clinical trials: May be suitable for studies of new drugs, combinations, and technologies
• Precautions (during treatment)
  • Clearly discuss and agree with the medical team on the treatment goals, expected side effects, and anticipated benefits
  • Monitoring is necessary for the risk of complications such as infection, bleeding, fracture, kidney failure, and decreased liver function
  • Emergencies (spinal cord compression, severe hypercalcemia, increased intracranial pressure, etc.) require immediate emergency treatment

Checklist Before an Outpatient Visit (Including Example Questions)

• Items to prepare
  • List of medications currently being taken (including prescription drugs, over-the-counter drugs, and dietary supplements)
  • Existing medical certificates, surgical records, and pathology reports (related to the primary cancer), and original copies or CDs of previous test results (imaging and blood tests)
  • Symptom diary (when symptoms started and how they have changed), and pain scale (0–10) records
  • History of allergies and chronic diseases (cardiovascular disease, diabetes, kidney disease, etc.)
  • Insurance and caregiver contact information, and support-person information if needed
• Key information to provide to the medical team during the outpatient visit
  • When symptoms began and how they have progressed (e.g., weight changes, fever, worsening pain)
  • Medications or supplements recently stopped or changed
  • Whether there are emergency symptoms (dizziness, chest pain, sudden shortness of breath, changes in consciousness)
• Prepare questions to ask during the outpatient visit (example sentences)
  • "How do the metastatic lesions appear on the recent imaging results?"
  • "What are the treatment goals from this point onward (what is the purpose of treatment)?"

Examples of General Questions to Ask the Doctor

• "Where are the metastatic lesions located and how many are there, and are resection or local treatment possible?"
• "What are the expected benefits (such as prolonged survival and symptom relief) and major side effects of the treatment you recommend?"
• "What additional tests are needed (molecular genetic testing, biopsy, inflammation or tumor markers, etc.)?"
• "What should I be careful about in daily life (infection prevention, activity restrictions, diet and medication use)?"
• "Is participation in a clinical trial possible, or are there other treatment options?"

Examples of Disease-Specific Questions

• "Which molecular tests (e.g., EGFR/ALK/BRCA/MMR, etc.) or immune markers (such as PD-L1) were performed on the primary cancer? Based on the results, what targeted therapies or immunotherapies are available?"
• "Considering the size, number, and location of the current metastatic lesions (e.g., in the liver, lungs, or bones), can local treatments such as surgical resection or stereotactic body radiation therapy (SBRT) be considered?"

(Additional guidance: The specific diagnosis and treatment plan vary depending on the type of primary cancer, stage, the patient's general condition, and test results. Please consult your treating physician to determine the necessary tests and treatment.)