Common Sites and Frequencies of Distant Metastasis in Breast Cancer

✅ Common Sites and Frequencies of Distant Metastasis in Breast Cancer (Approximate)

Distant metastasis in breast cancer (i.e., when cancer cells spread from the breast to other organs) most commonly affects the bones, lungs, liver, and brain. The following are approximate frequencies based on multiple studies. (Note: These may vary depending on the breast cancer subtype.)

Site of Metastasis	Approximate Frequency	Notes
Bone 🦴	About 65–75%	Most common. Can cause pain, fractures, or bone marrow issues.
Lung 🫁	About 15–25%	May cause cough or difficulty breathing.
Liver 🧫	About 10–20%	Often asymptomatic and found during routine scans.
Brain 🧠	About 5–15%	More common in HER2-positive and triple-negative subtypes.

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🔍 Additional Notes

• The subtype of breast cancer (e.g., hormone receptor-positive, HER2-positive, triple-negative) significantly affects where metastasis is more likely:
  • Hormone receptor-positive: Bone metastasis is more frequent.
  • HER2-positive: Liver and brain metastases are relatively more common.
  • Triple-negative: Lung and brain metastases are more likely.
• In many cases, the bone is the first site where metastasis is detected.

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