A 35-year-old BRCA1 mutation carrier with newly diagnosed triple-negative breast cancer (T1cN0M0) desires risk-reducing contralateral mastectomy at the same time as therapeutic mastectomy. The OncotypeDX recurrence score is not relevant here. Which pathological feature of triple-negative breast cancer most strongly correlates with response to neoadjuvant platinum-based chemotherapy?
- A High Ki-67 proliferation index
- B BRCA1 germline mutation status ✓
- C Presence of tumor-infiltrating lymphocytes (TILs)
- D Absence of androgen receptor expression
Correct answer: B. BRCA1 germline mutation status
Explanation
BRCA1 germline mutations in triple-negative breast cancer create homologous recombination deficiency, making tumors particularly sensitive to DNA-damaging agents like platinum compounds (carboplatin, cisplatin). The GeparSixto and CALGB 40603 trials showed improved pathologic complete response (pCR) rates with platinum addition specifically in BRCA-mutated TNBC. While TILs are predictive of immunotherapy response, and Ki-67 correlates with chemosensitivity generally, BRCA1 mutation status is the strongest predictor of platinum response in TNBC.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.