A 52-year-old woman undergoes breast-conserving surgery for a 2.1 cm invasive ductal carcinoma (ER+/PR+, HER2-negative, grade 2, pT2 N1 M0). Oncotype DX recurrence score returns as 18. What is the most appropriate adjuvant systemic therapy?
- A Chemotherapy followed by endocrine therapy
- B Endocrine therapy alone ✓
- C Trastuzumab plus endocrine therapy
- D CDK4/6 inhibitor plus endocrine therapy
Correct answer: B. Endocrine therapy alone
Explanation
The TAILORx and RxPONDER trials established that in node-positive, ER+/HER2-negative breast cancer with an Oncotype DX recurrence score ≤25, postmenopausal women derive no additional benefit from chemotherapy over endocrine therapy alone. A score of 18 falls in the low-risk range, and endocrine therapy alone is the standard. Trastuzumab is for HER2-positive disease. CDK4/6 inhibitors are added in metastatic disease or as extended adjuvant in specific high-risk settings, not based on a low recurrence score.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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Written and medically reviewed by the StethoPrep medical team.