Sensitivity to Endocrine Therapy Index Predicts Benefit from Weekly Adjuvant Paclitaxel for Hormone Receptor-Positive Breast Cancer in the GEICAM/9906 Trial.
Clin Cancer ResSep 1, 2026
Miguel Martín, Alvaro Rodriguez-Lescure, Cristina Reboredo et al.
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In 30 seconds
This randomized controlled trial evaluated the predictive value of the sensitivity to endocrine therapy (SETER/PR) index for the benefit of weekly adjuvant paclitaxel in hormone receptor-positive breast cancer. Among 567 analyzed tumors, a low SETER/PR index (<0.75) was associated with a significant improvement in distant recurrence-free interval (DRFI) with FEC + P (HR, 0.46; P = 0.035).
Key findings
- Low SETER/PR index was found in 16.2% of tumors analyzed.
- FEC + P significantly improved DRFI in patients with low SETER/PR (HR, 0.46; P = 0.035).
- No treatment benefit was observed for patients with SETER/PR ≥0.75 (HR, 1.02; P = 0.931).
- Differences in overall survival and breast cancer-specific survival did not reach significance.
Why it matters
The study highlights the potential of the SETER/PR index as a biomarker to guide treatment decisions in hormone receptor-positive breast cancer, particularly in identifying patients who may benefit from additional chemotherapy.