Disease Description (Causes and Symptoms)
- Definition: Lung metastasis is a condition in which malignant tumor cells originating in another part of the body reach the lungs through the bloodstream (or, rarely, the lymphatic system) and proliferate there.
- Pathophysiology: Because most of the systemic circulation passes through the lungs, many primary cancers readily metastasize to the lungs. Tumor cells become lodged in the lung capillaries, proliferate, and form nodules. In sarcomas, lymph node metastasis is relatively uncommon.
- Main causes (common primary cancers): Breast cancer, kidney cancer, osteosarcoma, thyroid cancer, and potentially any other type of cancer.
- Symptoms: Often asymptomatic. When symptoms occur, they may include cough, hemoptysis, shortness of breath (when the extent of metastasis is extensive), chest pain, and recurrent pneumonia/pulmonary hemorrhage.
- Diagnostic summary: Chest X-ray/CT may show a pulmonary nodule or multiple nodules; PET-CT is used to evaluate the primary site and check for metastases throughout the body. A biopsy (needle biopsy of the chest or pathological examination of a surgically resected specimen) distinguishes primary lung cancer from metastatic lesions (medical history and imaging findings also help with the diagnosis).
Treatment Methods and Precautions
- Treatment principles: Individualized treatment is provided based on the type of primary cancer, overall condition, number, size, and distribution of lung metastases, presence or absence of metastases to other organs, and lung function.
- Local treatment
- Surgery (metastasectomy): Considered when the primary cancer is controlled (or can be controlled), there are no or few metastases outside the lungs, and lung function is sufficient. Common resections include wedge resection and, when necessary, lobectomy and lymph node dissection.
- Radiation therapy: Local radiation (e.g., stereotactic ablative radiotherapy [SABR/SBRT]) may be used when systemic treatment is insufficient or for symptom relief.
- Systemic treatment
- Chemotherapy, targeted therapy, and immunotherapy are determined according to the type of primary tumor. Even when lung metastases are present, treatment follows the guidelines for the primary cancer.
- Conservative and supportive treatment: Oxygen therapy, pain medication, treatment for bleeding (if necessary), treatment of infection, and other measures.
- Complications and risks: Surgical complications (bleeding, pneumonia, pneumothorax), side effects of radiation/anticancer drugs (such as bone marrow suppression and pulmonary toxicity), and worsening shortness of breath.
- Self-care and precautions: Smoking cessation is recommended. Limit alcohol consumption during chemotherapy/radiation therapy. Avoid taking supplements or nutritional products without consulting a doctor (as they may cause liver or kidney toxicity). Infection prevention and early medical evaluation are necessary if respiratory symptoms develop.
Checklist Before an Outpatient Visit (Items to Bring and Example Questions)
- Items to bring
- List of medications and supplements currently being taken (including doses and administration times)
- Copies or CDs of previous test and imaging results (CT, PET-CT, MRI, pathology report from a biopsy)
- History of previous surgery, chemotherapy, and radiation therapy (year, institution, and treatment details)
- Record of changes in symptoms (onset date, frequency, and severity of cough, hemoptysis, and shortness of breath)
- Smoking status and amount, alcohol consumption, and allergy information
- Recent weight changes and overall condition (activity level; refer to ECOG/WHO performance status)
- Information to tell the doctor in advance during the outpatient visit
- Current symptoms (if severe, a visit to the emergency room may be recommended)
- If you have recent test results or a diagnosis from another hospital, bring copies
Examples of General Questions to Ask the Doctor
- Can it be determined with certainty whether this lung lesion is metastasis from the primary cancer? Is additional testing (a biopsy) necessary?
- What treatment options are recommended in my case, and what are the expected benefits and side effects of each?
- Is surgery possible, and to what extent could surgery help improve survival or symptoms?
- What precautions should I take in daily life during chemotherapy or radiation therapy?
Examples of Disease-Specific Questions
- Could my lung metastases be considered 'oligometastasis' (limited metastases) and be eligible for surgery or local treatment? What are the indications and risks of surgery?
- If the primary cancer is still unknown (when the source of the cancer is not known), what tests are recommended to locate the primary site, and when should a biopsy be performed?