A 38-year-old woman with locally advanced HER2+ breast cancer (T3N2M0) receives neoadjuvant trastuzumab + pertuzumab + docetaxel + carboplatin (TCHP). After surgery, pathological complete response (pCR) is NOT achieved. According to the KATHERINE trial, the most appropriate adjuvant therapy is:
- A Continue trastuzumab + pertuzumab for 1 year
- B Switch to trastuzumab emtansine (T-DM1) for 14 cycles ✓
- C Add lapatinib to trastuzumab
- D Continue trastuzumab monotherapy for 1 year
Correct answer: B. Switch to trastuzumab emtansine (T-DM1) for 14 cycles
Explanation
The KATHERINE trial demonstrated that patients with HER2+ early breast cancer who have residual invasive disease after neoadjuvant therapy (defined as having HER2+ disease and receiving neoadjuvant chemotherapy plus anti-HER2 therapy) have significantly improved invasive disease-free survival when switched to T-DM1 (trastuzumab emtansine) for 14 cycles compared to continuing trastuzumab. T-DM1 reduced the risk of invasive disease recurrence or death by 50% (HR 0.50). Pertuzumab addition (option A) is not standard adjuvant therapy post-neoadjuvant non-pCR.
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.