e12119 Background: Neoadjuvant endocrine therapy (NET) and neoadjuvant chemotherapy (NCT) are both considered effective strategies in postmenopausal, hormone receptor positive breast cancer patients. Small prospective studies show comparable response rates and breast conservation rates. Using National Cancer Data Base (NCDB) we report overall survival (OS) differences between these two strategies with subgroup analysis by Estrogen Receptor (ER), Progesterone Receptor (PgR) status. Methods: We extracted data on hormone receptor positive breast cancer patients without metastasis in women aged ≥ 50 from the NCDB registry (2004-2014). We excluded patients who did not receive adjuvant endocrine therapy after NCT and patients who received adjuvant chemotherapy after NET as this could affect OS. We calculated OS using Kaplan Meier analysis with hazard ratio (HR) from cox regression model. Subgroup analysis was performed by ER, PgR status. Results: Out of 2,246,279 patients, 30,348 patients met our inclusion criteria. 7836 received NET and 22512 received NCT. OS rate was 70.8% vs 81.7% at 5 yrs and 42.5% vs 62.1% at 9 yrs for NET and NCT respectively with adjusted hazard ratio (HR) of 1.818; 95% CI (1.657-1.996). OS outcome for ER+/PgR+ group was 72.3% vs 83.5% at 5 yrs and 43.5% vs 64% at 9 yrs for NET and NCT respectively with adjusted HR of 1.807; 95% CI (1.624-2.010). OS for ER+/pgR- group was 62.9% vs 76.8% at 5 yrs and 33.1% vs 54.2% at 9 yrs for NET and NCT respectively with adjusted HR of 1.890; 95% CI (1.549-2.306). Our analysis also revealed that 5591 T1 patients received neoadjuvant therapy among which 2541 received NET and 3050 received NCT. Conclusions: We find a significant survival advantage in patients treated with NCT as opposed to NET. All subgroups showed imporved OS with NCT compared with NET. Limitations that should be considered in this registry based study are: not accounting for Her-2 status, differences in surgical technique, duration and choices of adjuvant chemotherapy and radiotherapy options.
Neoadjuvant Endocrine Therapy as an Alternative to Neoadjuvant Chemotherapy Among Hormone Receptor-Positive Breast Cancer Patients: Pathologic and Surgical Outcomes