What types of cancer can metastasize to the lungs?

Common Cancers That Metastasize to the Lungs

The lungs are among the most common sites for cancer metastasis, with virtually any primary malignancy capable of spreading to the lungs, most frequently from cancers of the breast, colon, kidney, head and neck, thyroid, genitourinary tract, and sarcomas.

Primary Sites with High Lung Metastatic Potential

• Breast cancer is one of the most common primary tumors that metastasize to the lungs, with different subtypes showing varying lung tropism (basal-like breast cancer shows particular lung tropism) 1, 2
• Colorectal cancer frequently metastasizes to the lungs, with a distinctive immunohistochemical profile (TTF-1 negative, CK7 negative, CK20 positive, CDX-2 positive) that helps distinguish it from primary lung adenocarcinoma 3
• Head and neck squamous cell carcinomas commonly spread to the lungs and can mimic primary lung squamous cell carcinoma 3
• Renal cell carcinoma (hypernephroma) has a predilection for lung metastasis 4, 5
• Thyroid cancers, particularly papillary, follicular, and medullary carcinomas, can metastasize to the lungs and show strong TTF-1 immunoreactivity (similar to primary lung adenocarcinoma) 3, 4
• Melanoma is among the most common solid tumors to metastasize to the lungs 6, 2
• Sarcomas frequently metastasize solely to the lungs, and in some cases, surgical resection of isolated lung metastases may be curative 3, 4

Other Common Primary Sites

• Gastrointestinal tract cancers (stomach, pancreas, liver) frequently metastasize to the lungs 6, 2
• Genitourinary tract cancers (bladder, prostate, ovarian, endometrial, cervical) commonly spread to the lungs 6, 2, 5
• Lymphomas can involve the lungs, typically as part of widespread disease 3, 2
• Adrenal gland cancers can metastasize to the lungs 4

Patterns of Lung Metastasis

• Metastatic disease to the lungs typically presents as:

  • Pulmonary nodules (most common pattern) 6
  • Lymphangitic carcinomatosis 6
  • Endobronchial tumors 6, 5
  • Pleural involvement with effusion 3, 7

• Metastatic tumors from breast, colon, and prostate tend to show more expansile growth in the lung rather than the infiltrative growth with adjacent lung retraction more typical of primary lung cancers 3

Pathways of Metastasis to the Lungs

• The lungs are particularly susceptible to metastasis because they:

  • Receive the entire cardiac output every minute
  • Have the densest capillary bed in the body
  • Are the first reservoir of most lymphatic drainage entering the venous system 4

• Routes of metastasis include:

  • Hematogenous spread (most common)
  • Lymphatic spread
  • Direct extension (rare) 4

Clinical Implications

• Lung metastases may be asymptomatic or present with:

  • Cough (particularly with endobronchial involvement)
  • Hemoptysis
  • Dyspnea
  • Recurrent pulmonary infections 5

• Metastatic disease to the lungs significantly impacts prognosis and treatment planning 7

• Distinguishing primary lung cancer from metastatic disease is crucial for appropriate management and can be achieved through:

  • Clinical history and presentation
  • Radiographic patterns
  • Immunohistochemical analysis (TTF-1, CK7, CK20, CDX-2) 3

Diagnostic Considerations

• CT imaging with IV contrast is the preferred modality for detecting lung metastases 7
• PET/CT has high sensitivity for detecting metabolically active metastases 3
• Biopsy of suspected metastatic lesions is often necessary to confirm the diagnosis and origin of the primary tumor 3

Remember that while virtually any cancer can metastasize to the lungs, the most common primary sites are breast, colorectal, head and neck, kidney, and melanoma 6, 4.