253P - The difference in prognostic outcomes between de novo stage IV and recurrent metastatic patients with hormone receptor-positive, HER2-negative breast cancer: a single-center study

Abstract

The difference in prognostic outcomes between de novo stage IV and recurrent metastatic breast cancer is still unclear, and these patients have often been treated with the same treatment strategies. The objective of this retrospective single-center study was to compare prognostic outcomes between these patients, in particular patients with hormone receptor-positive (HR+), HER2-negative (HER2-) metastatic breast cancer. This analysis may help us to interpret results from current clinical research and propose future studies. This is a chart review study of de novo stage IV and recurrent metastatic patients with HR + /HER2- breast cancer, who were treated between January 2000 and December 2015 in Sakai City Medical Center, Japan. We used the Kaplan-Meier method to estimate overall survival of the two groups. The Cox proportional hazards model was used to examine the prognostic evaluation between the groups by using two prognostic indicators: disease-free interval (DFI) and interval from the end of adjuvant treatment to the first recurrence (AFI). We studied 145 patients, including 52 de novo stage IV and 93 recurrent metastatic patients with HR + /HER2- breast cancer. There was no significant difference in prognosis between the groups. However recurrent patients with DFI < 2 years were found to have significantly poorer prognosis compared with recurrent patients with DFI ≧ 2 years (hazard ratio (HR):2.108, 95%CI:1.146-3.876, p = 0.016), and de novo stage IV patients (HR:2.843, 95%CI:1.473-5.489, p = 0.002). Similarly, recurrent patients with AFI < 1 year had significant poorer prognosis compared with de novo stage IV patients (HR:1.330, 95%CI:1.034-1.711, p = 0.026). De novo stage IV breast cancer had better prognosis due to therapy-naive or less resistant metastatic disease compared with recurrent patients with DFI < 2 years or AFI < 1 year, who were likely to have an insufficient or non-carry-over effect of adjuvant treatment. If future efforts are conducted with a larger spectrum of patients and treatment analysis, results might be more conclusive.