328.1 🎓 醫孞生版

328.1.0.1 📌 䞀頁重點

328.1.0.1.1 Pulmonary Metastases
328.1.0.1.1.1 Epidemiology
  • Lung = #1 site of cancer metastasis
  • More common than primary lung cancer
  • 30-40% of cancer patients
  • Often multifocal
328.1.0.1.1.2 Routes
  • Hematogenous (most common) — through pulmonary artery
  • Lymphatic (lymphangitic carcinomatosis)
  • Bronchogenic (direct spread along airway)
  • Direct extension (esophageal, mediastinal)
328.1.0.1.1.3 Common Primary Tumors with Lung Mets
  • Breast (most common — 50-60% of breast cancer)
  • Colorectal (30-40%)
  • Kidney
  • Testicular (germ cell)
  • Head and neck
  • Melanoma (50-70%)
  • Sarcoma (high pulmonary metastasis rate)
  • Ovarian, prostate, bladder
  • Thyroid (papillary, follicular)
328.1.0.1.1.4 Patterns of Pulmonary Metastases

Multiple Bilateral Nodules (most common): - Hematogenous - Peripheral predominant - Variable size - Round, well-circumscribed

Solitary Metastasis: - Less common - Resembles primary - Hard to distinguish without history

Miliary Pattern: - 1-3 mm nodules - Thyroid (papillary), renal cell, melanoma, sarcoma

Lymphangitic Carcinomatosis: - Linear/reticular pattern - Often unilateral or asymmetric - Breast, GI, prostate - Worse prognosis

Endobronchial: - Renal cell, colon, breast - Airway obstruction - Bronchoscopic management

Pleural Metastases: - Malignant pleural effusion (Ch311) - Lung, breast, ovary, lymphoma

Cavitating: - Squamous (head/neck, lung) - Sarcoma - Colon

328.1.0.1.1.5 Clinical Features
  • Often asymptomatic (incidental finding)
  • Cough, dyspnea
  • Pleuritic chest pain
  • Hemoptysis (less common than primary)
  • Bronchial obstruction symptoms
328.1.0.1.1.6 Diagnosis

Imaging: - CT chest (often gold standard) - PET-CT (cancer staging) - Lung-only metastases vs systemic - Comparison to prior images

Tissue Biopsy: - CT-guided percutaneous (peripheral) - Bronchoscopy (central, endobronchial) - VATS for diagnosis + resection - IHC + molecular for primary identification

Molecular Studies: - For unknown primary - Genetic similarity to known primaries - Cancer-specific markers

328.1.0.1.2 Treatment of Pulmonary Metastases
328.1.0.1.2.1 Systemic Therapy (Depends on Primary)

Breast Cancer: - HER2+: trastuzumab, pertuzumab, T-DM1, T-DXd - HR+: endocrine therapy ± CDK4/6 inhibitor - TNBC: chemo + IO if PD-L1+

Colorectal Cancer: - FOLFOX, FOLFIRI, FOLFOXIRI - Anti-EGFR (cetuximab, panitumumab) for KRAS WT - Anti-VEGF (bevacizumab) - IO for MSI-H

Renal Cell Carcinoma: - TKIs (sunitinib, pazopanib, axitinib) - IO (nivolumab + ipilimumab; pembrolizumab + axitinib)

Melanoma: - IO (pembrolizumab, nivolumab, nivolumab + ipilimumab) - BRAF/MEK inhibitors

Testicular (Germ Cell): - Highly chemo-sensitive - BEP (bleomycin + etoposide + cisplatin) - Cure rate high even with lung mets

Sarcoma: - Doxorubicin + ifosfamide - Pazopanib (TKI)

328.1.0.1.2.2 Surgical Resection (Metastasectomy)

Criteria for Consideration: - Primary tumor controlled - No extrapulmonary mets (or controlled) - All lung mets resectable - Adequate pulmonary reserve - Disease-free interval > 1 year (often)

Approach: - VATS preferred (less invasive) - Multiple wedge resections - Lobectomy if necessary - Bilateral when needed - Repeat metastasectomy possible

Outcomes: - Colorectal: 30-50% 5-year survival - Sarcoma: 25-40% 5-year survival - Renal cell: 30-40% 5-year survival - Melanoma: less benefit - Germ cell: high cure with combined approach

Trials: - PulMiCC (2020): questioned metastasectomy benefit in colorectal (controversial) - Continued debate about routine metastasectomy

328.1.0.1.2.3 Local Therapy Alternatives

Stereotactic Ablative Radiotherapy (SABR): - For non-surgical candidates - Limited number of mets - Comparable outcomes for select - SABR-COMET trial (2019): oligometastatic improved OS

Radiofrequency Ablation (RFA): - Image-guided - For small lesions - Alternative to surgery

Microwave Ablation, Cryoablation: - Newer techniques - Selected cases

328.1.0.1.2.4 Oligometastatic Disease Concept
  • 1-5 metastases (definition varies)
  • Aggressive local therapy may improve OS
  • SABR-COMET trial: standard care + SABR vs standard ↑ OS (28% vs 18% 5-year)
  • Increasing acceptance
  • Combination with systemic therapy
328.1.0.1.3 Lymphangitic Carcinomatosis

328.1.1 Mechanism

  • Lymphatic spread of malignancy
  • Pleural + peribronchovascular thickening
  • Tumor cells within lymphatics

328.1.2 Clinical

  • Progressive dyspnea (rapid)
  • Cough
  • Hypoxemia
  • Poor prognosis (median 3-6 months)

328.1.3 Imaging

  • HRCT: linear/reticular pattern + interlobular septal thickening + peribronchovascular thickening
  • “Crazy paving” can occur

328.1.4 Treatment

  • Treat primary (systemic therapy)
  • Steroids may help (no clear evidence)
  • Often refractory
328.1.4.0.1 Paraneoplastic Pulmonary Syndromes

328.1.5 Hypertrophic Pulmonary Osteoarthropathy (HPOA)

  • Adenocarcinoma classically
  • Clubbing + periostitis + joint pain
  • Periosteal new bone formation
  • Resolves with treatment of cancer
  • Bisphosphonates may help

328.1.6 Trousseau Syndrome

  • Migratory thrombophlebitis
  • Hypercoagulability
  • Adenocarcinoma (lung, GI, pancreatic) classic
  • Treatment: LMWH (Caravaggio); DOAC OK for many

328.1.7 DIC (Disseminated Intravascular Coagulation)

  • Malignancy-associated
  • APML classically
  • Treatment: address primary + supportive

328.1.8 Erythrocytosis

  • Renal cell carcinoma (EPO-secreting)
  • Hepatocellular carcinoma
  • Cerebellar hemangioblastoma

328.1.9 Anemia of Chronic Disease

  • Multifactorial
  • Treatment: address primary

328.1.10 Pulmonary Tumor Embolism

  • Microscopic / macroscopic tumor in pulmonary vasculature
  • Rapid hypoxemia + RV failure
  • Choriocarcinoma classic
  • Treatment: chemotherapy

328.1.11 Drug-Induced Pulmonary Toxicity (from Cancer Treatment)

  • See Ch292
  • Chemotherapy: bleomycin, methotrexate, BCNU, gemcitabine
  • TKIs: gefitinib, erlotinib, osimertinib (rare ILD)
  • ICI: pneumonitis 5-10%
  • Recognition + steroid important

328.1.11.1 🩺 床邊速查

  • Lung = #1 metastasis site
  • Common primaries: breast, colon, kidney, testicular, head/neck, melanoma, sarcoma
  • Patterns: multiple bilateral nodules (most), solitary, miliary, lymphangitic, endobronchial, pleural
  • Metastasectomy criteria: controlled primary + no extrapulmonary mets + all resectable + adequate reserve
  • Oligometastatic + SABR-COMET 2019: aggressive local therapy may ↑ OS
  • Lymphangitic carcinomatosis: rapid progressive dyspnea, poor prognosis
  • HPOA: clubbing + periostitis (adenocarcinoma)
  • Trousseau syndrome: migratory thrombophlebitis (cancer-associated)