AB006. SOH22ABS118. Neoadjuvant chemotherapy prescription in estrogen receptor positive breast cancer in the west of Ireland

Background: Estrogen receptor positive (ER+) breast cancers is a hormone sensitive disease, response well to endocrine therapies and carry favourable prognoses. Recently, there has been a vogue to prescribe neoadjuvant chemotherapy (NACT) for patients diagnosed with ER+ breast cancer.

Methods: Consecutive female patients treated with NAC for ER+ breast cancer managed in a single institution between 2005–2015 were included. Descriptive statistics were used as appropriate to outline clinicopathological and treatment data. Miller Payne Grade (MPG) was used to assess response to NAC. Survival analyses were performed using Cox regression and log-rank Kaplan-Meier analyses.

Results: A total of 308 patients were included with a median age of 51.8±12.6 years (range, 21–87 years). Median follow-up was 86.3 months. MPG was available for 229 patients; 26 achieved a pCR (MPG 5) to NAC (11.4%), 134 patients had a good response to NAC (MPG 3–4) (58.5%) and 69 had a poor response (MPG 1–2) (30.1%). Using Kaplan Meier analyses, MPG failed to predict DFS (P=0.100) or OS (P=0.274). However, patients achieving a pCR had enhanced DFS (P=0.004) and OS (P=0.033). Furthermore, successfully achieving a pCR predicted enhanced DFS [hazard ratio (HR): 0.098, 95% confidence intervals (CIs): 0.014–0.702, P=0.021] and OS (HR: 0.245, 95% CIs: 0.060–0.998, P=0.049).

Conclusions: There is a varying response to NAC in patients diagnosed with ER+ breast cancer. In-vivo data obtained from NAC may inform patient prognostication in ER+ breast cancer.

Keywords: Breast; endocrine; hormone responsive; neoadjuvant; prescription