Utility of estrogen receptor, progesterone receptor, and HER-2/neu analysis of multiple foci in multifocal ipsilateral invasive breast carcinoma.
OBJECTIVES
To determine the frequency of estrogen receptor (ER), progesterone receptor (PR), and HER-2/neu (HER2) testing multiple foci of ipsilateral invasive breast carcinoma at our institution and to evaluate resulting change in treatment recommendation.


METHODS
We identified 165 consecutive cases of multifocal invasive breast cancer over a 10-year period (2005-2014). Clinicopathologic features and treatment recommendation were assessed by slide and chart review.


RESULTS
Seventy (42.4%) of 165 patients had two or more foci tested. In the first 6 years (2005-2010), frequency of testing two or more foci was 31.6% and increased to 70.6% in 2014. Seven (10%) of 70 had a clinically significant difference in ER/PR and/or HER2 status, five (7.1%) with a difference in HER2, one (1.4%) in ER/PR, and one (1.4%) in both ER/PR and HER2. All cases with difference in status had different histology and/or the largest focus was the most positive one.


CONCLUSIONS
Our findings support current recommendations to evaluate additional smaller tumor foci in multifocal invasive breast cancer if the focus is of different grade or histology. Additional features, including specific histology, grade, and ER, PR, and HER2 status of the largest focus, should also be considered when selecting cases for which testing of additional foci may be of benefit.
['East|Ellen G|EG|', 'Pang|Judy C|JC|', 'Kidwell|Kelley M|KM|', 'Jorns|Julie M|JM|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D014408:Biomarkers, Tumor D001943:Breast Neoplasms D005260:Female D006801:Humans D007150:Immunohistochemistry D008875:Middle Aged D009378:Neoplasms, Multiple Primary D018719:Receptor, ErbB-2 D011960:Receptors, Estrogen D011980:Receptors, Progesterone
Estrogen receptor Progesterone receptor HER-2/neu Multifocal Breast Carcinoma ER PR Cancer