The influence of prognostic factors on metastatic breast cancer survival over time.

1589 Background: Recent evidence suggests that survival in metastatic breast cancer is slowly improving associated with the use of better adjuvant and metastatic chemotherapeutic and targeted agents. Patient and clinical factors such as age, estrogen status, non-white race, Her 2 status, disease free interval and sites of metastatic breast cancer involvement indicate worse clinical outcome after recurrence. This analysis focused on the influence of these factors on metastatic breast cancer survival over time. Methods: Subjects were women with metastatic breast cancer from one large urban practice, of the University of Pittsburgh Cancer Institute Breast Cancer Program followed from 1999 through December, 2008. Patients were dichotomized into two time categories: A) 1999 through 2004 and B) 2005 through 2008. Outliers of long term survivors (n =72) with survival extending beyond 6 years were excluded. Log rank tests were conducted for assessing the relationship between prognostic factors and survival. Results: Cohorts included patients diagnosed with metastatic breast cancer in 1999 through 2004, (n=284) and 2005 through 2008, (n=332). They were followed up to December, 2011. Median survival improved over time (p=0.053). Estrogen negativity remained significant for worse survival across both time periods (p<0.0001). Age, presence of brain metastasis and Her 2 status were not significant for influence on survival at either time interval. Shorter disease free interval (p= 0.02), higher number of metastatic sites (p=.001) and presence of visceral metastasis at diagnosis (p=0.003) became significant for worse survival in the 2005-2008 intervals but had not been in the earlier time period. African American race was highly significant (<0.001) for worse survival in 1999-2004 but lost significance in 2005 through 2008 with dramatic survival increase (median survival - 12.5 months to 35 months). Conclusions: It is important for clinicians to clarify the prognostic features associated with worse outcomes in metastatic breast cancer. With newly emergent therapies and sensitivity toward specific patient factors these features evolve over time.