Discordance in Estrogen Receptor, Progesterone Receptor and HER2 Status between Breast Primary Cancers and Respective Recurrences
Debra A Budwit, Siobhan M O'Connor, Carey K Anders. University of North Carolina, Chapel Hill, NC
Background: Estrogen receptor (ER), progesterone receptor (PR) and (HER2) status is of prognostic and targeted therapeutic importance for patients with breast cancer. Receptor status may change between primary breast cancer and respective recurrences. Limited data are available regarding the discordance rates for receptor status overall for relapses, and less for the discordance rates for the subcategories of local recurrences (LR), distant visceral metastases (VM) and bone metastases (BM).
Design: Pathology computer files searched from 1/1/2006 to 7/1/2012 revealed 82 patients with 87 breast cancer recurrences (9 LR, 54 VM, 24 BM) for which ER/PR/HER2 receptor status had been determined. ER and PR were evaluated by immunohistochemistry (IHC), and were considered positive if 1% or more of cells had positive nuclear staining. HER2 was evaluated by IHC for overexpression and/or fluorescence in situ hybridization (FISH) for gene amplification. HER2 was considered positive if the IHC score was 3+ for membranous overexpression and/or positive for gene amplification by FISH. The receptor status of the recurrences was compared to that of the respective primary breast cancers. Discordance rates were determined for overall recurrences and for the LR, VM and BM subcategories.
Results: Fifty-four (66%) of patients were concordant for all three ER/PR/HER2 results between breast primary cancers and recurrences. Overall discordance rates were ER 11%, PR 18% and HER2 14%. Of 14 triple negative primary breast cancers, 2 (14%) were ER positive in the recurrences. The results for discordant cases are summarized in Table 1.
|ER pos to neg||ER neg to pos||PR pos to neg||PR neg to pos||HER2 pos to neg||HER2 neg to pos||Total|
|Total||7 (8%)||3 (3%)||14 (16%)||2 (2%)||7 (8%)||5 (6%)|