Trends in endocrine therapy prescription and survival in patients with non-metastatic hormone receptor positive breast cancer treated with endocrine therapy: A population based-study

PURPOSE: To identify prognostic factors of invasive–disease free survival (iDFS) in women with non-metastatic hormone receptor positive (HR+) breast cancer (BC) in daily routine practice. METHODS: We performed a retrospective study using data from the Côte d’Or breast and gynecological cancer registry in France. All women diagnosed with primary invasive non-metastatic HR + BC from 1998 to 2015 and treated by endocrine therapy (ET) were included. Women with bilateral tumors or who received ET for either metastasis or relapse were excluded. We performed adjusted survival analysis and Cox regression to identify prognostic factors of iDFS. RESULTS: A total of 3976 women were included. Age at diagnosis, ET class, SBR grade, treatment, stage and comorbidity were independently associated with iDFS. Women who had neither surgery nor radiotherapy had the highest risk of recurrence (HR = 3.75, 95%CI [2.65–5.32], p < 0.0001). Receiving aromatase inhibitors (AI) was associated with a lower risk of recurrence (HR = 0.70, 95%CI [0.54–0.90], p = 0.055) compared to tamoxifen. Compared to women with no comorbidities, women with 1 or 2 comorbidities were more likely to receive AI (OR = 1.63, 95%CI [1.22–2.17], p = 0.0009). CONCLUSIONS: Comorbidities, age at diagnosis and previous treatment were associated with iDFS in non-metastatic HR + BC patients. This study also showed that women who received tamoxifen for their cancer experienced worse iDFS compared to women treated with AI.