What is the prognosis for metastatic triple negative breast cancer?

Prognosis for Metastatic Triple Negative Breast Cancer

Metastatic triple-negative breast cancer (TNBC) carries a poorer prognosis compared to other breast cancer subtypes, with patients experiencing peak risk of recurrence within 3 years of diagnosis and increased mortality rates for 5 years after diagnosis. 1

Survival Outcomes

• Median overall survival (OS) for patients with metastatic TNBC is approximately 12.1 months with newer targeted therapies like sacituzumab govitecan, compared to 6.7 months with traditional chemotherapy 2
• In real-world studies, median OS ranges from 20.8 to 22.1 months regardless of PD-L1 status 3
• Median progression-free survival (PFS) is approximately 5.6 months with newer agents compared to 1.7 months with traditional chemotherapy 2
• A meta-analysis of mTNBC subgroups reported pooled objective response rate (ORR) of 23%, median OS of 17.5 months, and median PFS of 5.4 months with first-line single-agent chemotherapy 4

Risk Factors Associated with Worse Prognosis

• African-American race/ethnicity (TNBC is three times more common in women of African descent) 1
• Younger age at diagnosis 1
• More advanced disease stage at presentation 1
• Higher tumor grade and high mitotic indices 1
• Non-Hispanic black women with late-stage TNBC have particularly poor outcomes, with a 5-year relative survival of only 14% 1

Disease Characteristics

• TNBC represents 10-20% of all invasive breast cancers 1
• TNBC is characterized by absence of estrogen receptor (ER), progesterone receptor (PR), and no overexpression of human epidermal growth factor receptor 2 (HER2) 1
• TNBC is associated with BRCA1 mutations and family history of breast cancer 1
• Approximately 75% of TNBCs are basal-like breast cancers 1

Treatment Response and Prognosis

• Responses to traditional chemotherapy are generally not durable, with median duration of response (DOR) to first-line chemotherapy of 4.4-6.6 months 4
• Second-line or later chemotherapy has a pooled ORR of only 11% 4
• Newer targeted therapies have improved outcomes:
  • PARP inhibitors (olaparib, talazoparib) for patients with germline BRCA mutations 5
  • Immunotherapy (atezolizumab plus nab-paclitaxel) for PD-L1-positive tumors 5
  • Sacituzumab govitecan for heavily pretreated patients showing improved survival (median OS 12.1 months vs 6.7 months with chemotherapy) 2

Prognostic Considerations

• Patients with metastatic TNBC should be tested for actionable biomarkers that may improve prognosis:
  • PD-L1 status (for immunotherapy eligibility) 1
  • Germline BRCA1/2 mutation status (for PARP inhibitor eligibility) 1
  • PIK3CA mutations in some cases 1
• The prognosis may vary based on response to specific targeted therapies, with newer agents showing improved survival outcomes compared to traditional chemotherapy 2, 5

Metastatic Patterns

• TNBC has a higher propensity for visceral metastases compared to bone metastases 1
• There has been an increase in liver and central nervous system metastases over time 1
• The pattern of metastatic spread can impact prognosis, with CNS involvement generally associated with poorer outcomes 1