AB004. SOH22ABS111. Relapse patterns in estrogen receptor positive breast cancer

Background: Estrogen receptor positive (ER+) breast cancer is the most common breast cancer molecular subtype. The natural history of ER+ breast cancer involves good prognoses, however, when recurrences occur, they are associated with poor outcomes.

Methods: Consecutive female patients with ER+ breast cancer managed in a single institution between 2005–2015 were included. Patterns of locoregional and distant disease recurrence were outlined using descriptive statistics. Disease-free survival (DFS) and overall survival (OS) were determined using Kaplan-Meier (log-rank) analyses. Statistical analyses were performed using SPSS v26.0.

Results: A total of 2,660 patients were included with a median age of 59.6±13.3 years (21–99 years). Median follow-up was 97.2 months (3.0–181.2 months). Overall, 5.6% of patients had metastatic disease at presentation (149/2,660). At median follow up, 12.4% of patients suffered a recurrence (450/2,660): 2.1% of patients suffered a locoregional recurrence (56/2,660) and 10.3% patients suffered distant recurrence (394/2,660). The median time to relapse for patients suffering locoregional recurrence was 53.1 versus 48.1 months for those suffering distant recurrence. Of those suffering disease recurrence or death, bone was the most common initial site of distant recurrence (18.8%, 74/394), followed by liver (18.0%, 71/394) followed by lung recurrences (5.3%, 21/394) and then brain recurrences (5.1%, 20/394).

Conclusions: In patients with ER+ breast cancer, relapse occurs most commonly to bone, liver, lung and brain. The development of novel therapeutic strategies to prevent relapses are crucial in increasing the longevity of life for those diagnosed with ER+ breast cancer.

Keywords: Distant; estrogen; locoregional; patterns; recurrence