Utilization, trend and impact of neoadjuvant endocrine therapy compared to neoadjuvant chemotherapy in postmenopausal breast cancer patients: Analysis of the National Cancer Data Base.

Abstract

578 Background: Three small prospective trials that compared the efficacy of neoadjuvant endocrine therapy (NET) to neoadjuvant chemotherapy (NCT) showed no statistically significant difference. We report the differences in utilization of NET and NCT using National Cancer Data Base (NCDB) and their trend, response rates (RR) and breast conservation rates (BCR). Methods: A retrospective review of hormone receptor positive breast cancer patients ≥ 50 yrs without metastasis using NCDB was performed (2004-2014). Patients underwent NET or NCT prior to definitive surgery. Utilization pattern, practice trend, RR and BCR between NET and NCT was assessed using univariate and multivariate logistic analysis. Results: Out of 2,246,279 breast cancer patients reported in NCDB, 38,632 met our inclusion criteria. 9178 received NET and 29,454 received NCT. On multivariate analysis NET use was higher in academic vs community centers [Odds ratio (OR) 1.355, 95% CI 1.270-1.445], age >70 vs < 70 (OR 6.603, 95% CI 6.110-7.137) and high vs low Charlson Deyo comorbidity index (OR 1.817, 95% CI 1.548-2.133). NET use was lower in black vs white (OR 0.790, 95% CI 0.712- 0.875), tumors with higher vs lower grade (OR 0.153, 95% CI 0.138-0.169), higher vs lower T stage (OR 0.372, 95% CI 0.340-0.407), higher vs lower N stage (OR 0.274, 95% CI 0.243-0.310) and private vs no insurance (OR 0.600, 95% CI 0.509- 0.707), (all p<0.0001). A significant upward trend in utilization of NET was observed from year 2011 (25.9%) compared to before (22.2%), p<0.0001. RR was significantly higher for patients receiving NCT (90.5%) compared to NET (77.2%), with an [adjusted OR (aOR) 2.413; 95% CI 2.116-2.752], however the BCR was superior in the NET group (50.0%) compared to NCT group (31.1%) with (aOR 1.676; 95% CI 1.567-1.794). Conclusions: Our study is the first to compare NET and NCT utilization and their efficacy using NCDB database. Our results have shown striking differences in outcome among these two strategies as compared to other prospective trials. Despite high RR, more patients underwent mastectomy in the NCT group. We also see a steady upward trend in usage of NET from year 2011.