[261] Organotropism and Prognostic Marker Discordance in Distant Metastases of Breast Carcinoma: Fact or Fiction? A Clinicopathologic Analysis.

Paul E St. Romain, Rashna Madan, Ossama W Tawfik, Ivan Damjanov, Fang Fan. University of Kansas Medical Center, Kansas City

Background: Prior studies have suggested that the type of breast cancer influences the location of distant metastases (“organotropism”), and that there may be discordance of ER and Her2 expression between primaries and metastases. The aim of this study was to review breast cancers with distant metastases to further elucidate the relationship between tumor type and metastatic site, and to compare biomarker expression between primary and metastatic tumors.
Design: We retrospectively identified 102 biopsy-proven cases of breast cancer metastatic to distant sites from 2000 to 2010. These cases were paired with corresponding primaries and reviewed for histologic subtype, grade, lymphvascular invasion (LVI), lymph node metastasis (LNM), and expression of ER and Her2.
Results: Ages ranged from 29-90 years (mean 55) at time of biopsy-proven metastasis. Time from diagnosis of primary to metastasis ranged from 0 years (metastases at presentation) to 22 years. Histologic subtypes included ductal (88), lobular (11), metaplastic (1), mucinous (1), and mixed ductal/lobular (1). Metastatic sites for all types excluding lobular included lung, bone/bone marrow, skin, cervix, liver, omentum, brain, pleural fluid, esophagus, colon, and stomach. Additional unique metastatic sites for lobular included peritoneum, gallbladder, pancreas, small intestine, appendix, ovary and fallopian tube. Over half the primaries with available data were grade III (III = 25, II = 13, I = 2; n = 40). The majority of cases with available data on LNM and LVI were positive at time of primary diagnosis (37/45 and 18/30 respectively). Biomarkers were available on 73 metastases: 37 were ER+/Her2-, 6 were ER+/Her2+, 8 were ER-/Her2+, and 22 were ER-/Her2-. We found no association between ER/Her2 profile and metastatic site. Out of 34 cases with paired prognostic markers for primary and metastatic sites, 7 (20%) demonstrated discordance in ER/Her2 profile between the primary and the metastasis.
Conclusions: (1) We did not find evidence of organotropism of metastases when primary breast cancers were grouped by ER/Her2 profile. Also, the tendency to biopsy the most accessible organ in cases of multi-organ involvement introduces a bias into this type of analysis. (2) As reported previously, lobular carcinoma had a striking predilection to metastasize to abdominal organs when compared to non-lobular carcinoma. (3) The ER/Her2 profile of metastatic breast cancer did not always match that of the primary tumor. Hence, it is important to repeat the prognostic markers of metastasis.
Category: Breast

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 25, Monday Morning

 

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