What cancers commonly metastasize to the adrenal glands, liver, and peritoneum?

Common Sites of Cancer Metastasis to Adrenal Glands, Liver, and Peritoneum

Lung cancer, breast cancer, gastric cancer, and melanoma are the most common primary cancers that metastasize to the adrenal glands, liver, and peritoneum. 1, 2, 3

Adrenal Gland Metastases

• Lung cancer is the most common primary tumor that metastasizes to the adrenal glands, accounting for approximately 35% of adrenal metastases 2

• Other common primary tumors that metastasize to the adrenal glands include:

  • Gastric cancer (14%) 2
  • Esophageal cancer (12%) 2
  • Liver/bile duct cancers (10%) 2
  • Breast cancer 3
  • Melanoma 3

• Adrenal metastases are often bilateral (49% of cases) and frequently asymptomatic, discovered incidentally during imaging or autopsy 2

• Adrenal metastases are one of the most common sites of metastatic disease in non-small cell lung cancer (NSCLC), along with brain, bone, liver, and pleura 1

Liver Metastases

• Common primary tumors that metastasize to the liver include:

  • Colorectal cancer 1
  • Breast cancer 1, 4
  • Lung cancer 1, 4
  • Gastric cancer 1
  • Pancreaticobiliary malignancies 1
  • Melanoma 4

• Liver metastases from gastric cancer often present as multiple nodules occupying both lobes and frequently coexist with extrahepatic disease 1

• The pattern of liver metastasis follows both anatomical/mechanical pathways (where portal circulation delivers tumor cells to the liver first) and the "seed and soil" hypothesis (where tumor cells preferentially grow in organs that provide favorable microenvironments) 4

Peritoneal Metastases

• Primary tumors that commonly metastasize to the peritoneum include:

  • Intra-abdominal cancers (most common): colorectal and ovarian cancer 5
  • Extra-abdominal cancers (9% of peritoneal metastases): 5
    • Breast cancer (40.8% of extra-abdominal primaries) 5
    • Lung cancer (25.6% of extra-abdominal primaries) 5
    • Melanoma (9.3% of extra-abdominal primaries) 5

• Gastric cancer has a particular propensity to metastasize via direct peritoneal dissemination from the serosal surface 1

• Lobular breast cancer has a unique tendency to metastasize to the peritoneum, similar to gastric cancer, likely due to specific molecular characteristics 4

Metastatic Pathways and Mechanisms

• Malignant tumors spread through three main pathways: 4

  • Lymphatic route
  • Hematogenous route (via blood vessels)
  • Direct dissemination into body cavities (particularly the peritoneum)

• The "seed and soil" hypothesis suggests that tumor cells (seeds) preferentially grow in specific organs (soil) that provide a favorable microenvironment 4

• The anatomical/mechanical hypothesis proposes that metastatic patterns follow vascular drainage patterns, with the first site determined by blood flow from the primary tumor 4

• Gastric cancer demonstrates heterogeneous metastatic behavior, with some tumors following the anatomical route (liver first, then lung) while others follow the seed-and-soil route with distant metastases without liver involvement 4

Clinical Implications and Prognosis

• Metastatic disease to the adrenal glands, liver, or peritoneum generally indicates advanced disease with poor prognosis 2, 5
• Median survival from diagnosis of peritoneal metastases from extra-abdominal cancers is approximately 5.8 months 5
• Adrenal metastases are often asymptomatic but can occasionally cause adrenal insufficiency when bilateral involvement is extensive 3
• In selected cases of isolated adrenal metastasis from lung cancer, surgical resection may be considered as treatment for localized disease rather than systemic spread 6
• For liver metastases from gastric cancer, surgical resection may be considered in highly selected patients with solitary metastases, with 5-year survival rates ranging from 0% to 37% 1

Diagnostic Considerations

• Adrenal masses in patients with known malignancy should be evaluated to distinguish between benign adrenal tumors and metastases 1
• Biopsy of adrenal tumors is generally contraindicated due to risk of tumor spillage and poor diagnostic power, but may be indicated in patients with a history of extra-adrenal cancers to confirm metastasis 1
• Imaging characteristics that suggest malignancy in adrenal masses include:
  • Inhomogeneous appearance on CT or MRI 1
  • Irregular margins 1
  • Irregular enhancement of solid components after contrast administration 1
  • High Hounsfield units (>10) on unenhanced CT 1