Estrogen/Progesterone Receptor (ER/PR) and HER2 Expression Profiles in Breast Cancers (BCs) with Isolated Bone Metastasis (IBM) Are Different from Those in BCs with Metastasis to Other Sites
S Wei, O Hameed. University of Alabama School of Medicine, Birmingham, AL
Background: Bone is a common site of relapse after treatment for primary BC and up to 90% of patients with terminal BC have bone metastasis. The aim of this study was to identify the clinical and pathological features of BC with IBM and compare them to those in cases with metastasis at other sites.
Design: The tumor registry at the authors' institution was searched to identify cases of BC with associated metastasis. These were then classified into cases with IBM, isolated or multiple visceral organ (e.g. lung, liver, ovary) metastasis (IVM or MVM), central nervous system metastasis (CNSM) [isolated (ICNSM) or combined with visceral organ(s)], or with multiple metastases (MM) of any combination. The status of ER/PR and HER2 expression and the time to relapse were then compared between the different groups.
Results: Of 2,738 patients with BC diagnosed between 1997 and 2003, 356 patients had metastatic disease at diagnosis or later. The proportion of cases with IBM that expressed ER/PR (52/59; 88%) was higher than that in cases with MM (50/96; 52%) (p<0.0001) and than that in cases with non-bone metastases (49/81; 60%) (p<0.001), including cases with IVM (28/49; 57%) (p<0.001), MVM (9/15; 60%) (p<0.0001), and ICNSM (12/17; 71%) (p=0.1). The distribution of BC molecular subtypes in cases of IBM was significantly different from that in the remainder.
|Metastatic organs||Luminal A type (ER/PR+/HER2-)||Luminal B type (ER/PR+/HER2+)||HER2 type (ER/PR-/HER2+)||Triple negative (ER/PR-/HER2-)||P value (vs. IBM)|
Of 203 originally metastasis-free patients, 38, 30, 12 and 80 eventually developed IBM, IVM, ICNSM, or MM, respectively. The mean time to relapse in cases with IBM (40.2 mo) was slightly less than that in cases with IVM (44.2 mo) (p>0.05) but more than that in cases with ICNSM (18.8 mo) (p<0.05) and MM (31.0 mo) (p<0.05).
Conclusions: The ER/PR and HER2 expression profiles of BC patients with IBM are different from than those in patients with non-bone metastasis or those with MM. Although it is unclear at this point how the expression of these markers is affecting the distribution of distant metastasis, such differences could potentially be utilized in determining the most appropriate survey mechanism for follow up of patients with non-metastatic disease. Evaluation of additional clinical and pathological differences between these groups is ongoing.
Monday, March 9, 2009 9:30 AM
Poster Session I Stowell-Orbison/Autopsy Award # 55, Monday Morning