Breast cancer recurrence and related mortality in U.S. pts with early breast cancer

738 Background: An understanding of the relationship between breast cancer (BC) recurrence and mortality in pts with early BC is important. The objective of this study, therefore, was to evaluate this relationship among a mid-western health system population. Methods: A retrospective cohort study of 1616 pts (mean age 60 yrs) with early BC (stage I and II) was conducted using data from a large integrated health care system. Information on demographics, disease characteristics/treatment, evidence/type of recurrence, and death was obtained. Kaplan-Meier estimates were used to compare overall and BC-related mortality between recurrence types, and also between each recurrence type and a control group without recurrence. For each comparison, hazard ratios (HR) were estimated after controlling for baseline covariates. Results: During a median follow-up of 44.5 (range 6.1–98.3) months, there were 192 (11.9%) recurrence events (26.1% loco-regional, 15.6% contralateral, 58.3% distant) and 188 (11.6%) deaths due to any cause, of which 85 (5.3% of study population) were BC-related. Compared with the non-recurrence group, the distant recurrence group showed the highest risk of death (HR=13.6, p<.001), followed by the loco-regional recurrence group (HR=4.5, p<.001), and the contralateral recurrence group (HR=3.0, p=.01). The 5-year overall survival probability for distant, loco-regional, contralateral recurrence, and pts without recurrence was 41.3%, 59.3%, 83.4%, and 91.7%, respectively. Median time to all-cause mortality for pts with distant, loco-regional, and contralateral recurrence was 41.2, 76.9, and 89.5 months, respectively. A similar trend was observed for BC-related mortality, with a significantly higher risk of BC-related death in the distant recurrence group vs women with loco-regional recurrence (HR=3.6, p<.001). Conclusion: The study shows that BC recurrence, irrespective of type of recurrence, is associated with increased mortality in pts with early BC. This effect on mortality is substantially more pronounced in pts with distant recurrence. Therapies shown to reduce the risk of BC recurrence are likely to have a significant beneficial effect on survival in pts with early BC. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration AstraZeneca AstraZeneca AstraZeneca AstraZeneca