Nishant Tiwari, Chief Hematology and Oncology Fellow at OU Health Stephenson Cancer Center, shared on X:
“Neoadjuvant Rx for ER+/HER2- Breast Cancer. Educational points, not medical advice.
- Chemo (anthracycline+taxane) is commonly used – but ER+/HER2- tumors are less chemo-responsive than TNBC/HER2+ (pCR ~7-17% vs 30-50%)
- Neoadjuvant endocrine therapy (AI in postmenopausal, or goserelin+AI in select premenopausal*) is a good alternative – similar response/BCS rates as chemo, far less toxicity. Best for strongly ER+ (≥50%/Allred 7-8), low Ki67 (<10-15%), low-grade tumors. Typical duration: 4-6mo, extendable to 12mo if still responding
- Frail/elderly (≥75, high comorbidity) patients: NET is often the best option, sometimes even as long-term primary therapy if surgery isn’t feasible
- ER-low (<10%): Now reclassified as TNBC – treat per KEYNOTE-522 regimen with neoadjuvant pembrolizumab, continued till a total treatment duration (Neoadjuvant + Adjuvant) of ~1 year.
- Genomic assays (Oncotype RS, EndoPredict) + Ki67 dynamics can guide chemo vs. endocrine choice, but remain investigational in the neoadjuvant setting* – not yet standard practice.
- CDK4/6 inhibitors + endocrine therapy show promise in the neoadjuvant setting but no survival data yet*
- Bottom line: regardless of neoadjuvant approach, ALL ER+ patients continue adjuvant endocrine therapy
*weaker/limited evidence (small or phase II trials, investigational)
Open for feedback and corrections!”
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