Prognostic Factors in Breast Carcinoma (BC) with Distant Metastasis.
Shi Wei, Zhiyong Ren, Yufeng Li, Omar Hameed. University of Alabama at Birmingham
Background: Most fatalities from BC are due to metastases that are resistant to adjuvant therapies. Thus, factors associated with clinical outcomes in patients with metastatic BC are of significant importance. To date, a number of prognostic factors have been constituted in early BC, including tumor size, nodal status, estrogen/progesterone receptor (ER/PR) and HER2 status. However, markers with prognostic power in advanced BC have not been well established. The aim of this study was to identify the clinicopathological factors significant for survival in patients with metastatic BC.
Design: We analyzed all BC patients with distal organ (bone, visceral organ, brain) metastasis in our institution between 1997 and 2003. The clinicopathologic factors were examined, including age, race, tumor size, tumor type, histologic grade, number of positive nodes, ER, PR and HER2 status, to identify factors significant for survival postmetastasis.
Results: Of 2,738 BC patients diagnosed between 1997 and 2003, 198 had distant metastasis either at the time of diagnosis (n=64) or subsequently (n=134). By univariate analysis, age, race, tumor size and number of positive nodes were not associated with clinical outcomes after metastasis, whereas histologic grade [p=0.005, hazard ratio (HR)=1.3 (1.1-1.6)], ER [p=0.0001, HR=0.5 (0.4-0.7)], PR [p=0.0001, HR=0.5 (0.4-0.7)], and HER2 status [p=0.04, HR=0.7 (0.5-0.9)] of the primary tumor were significantly associated with survival. Multivariate analysis revealed that only PR [p=0.004, HR=0.6 (0.4-0.9)] and HER2 status [p=0.004, HR=0.5 (0.3-0.7)] were significant while ER status was borderline [p=0.06; HR=0.7 (0.5-1.0)].
Conclusions: While the prognostic variables in early BC have been established, such knowledge is not entirely applicable to advanced BC. Compared to other clinical and pathological findings, our findings indicate that biomarker expression is better associated with outcomes after the development of metastatic disease. Specifically, we found that PR expression was independently associated with outcome and may add significant prognostic value beyond ER expression alone, especially since the latter was a relatively weaker prognostic biomarker. Another significant finding was the fact that HER2 overexpression/amplification was associated with a more favorable outcome in this patient cohort. It is unclear why this is in contrast to the worse prognosis associated with HER2 in early BC but could potentially be related to better response to specific targeted therapies. Further evaluation of this may provide new insights into BC biology and clinical decision making.
Monday, February 28, 2011 1:00 PM
Poster Session II # 38, Monday Afternoon