Relationship between implementation of the American Society of Clinical Oncology/College of American Pathologists guideline recommendations for breast core-needle biopsies and delay in therapy for patients with breast cancer.

Abstract

26 Background: Recently the ASCO/CAP suggested new guideline recommendations for immunohistochemical (IHC) testing of biomarkers in breast cancer. An algorithm that relies on accurate, reproducible assay performance was proposed and preanalytical, analytical and postanalytical standards suggested. One such recommendation is to have appropriate internal controls when assessing hormone expression. In this retrospective study we evaluated 242 breast core biopsy specimens to assess the impact of the recently proposed ASCO/CAP guideline recommendations and its possible impact on routine daily practice. In addition, we explore the impact of blindly selecting a random core for potential future studies. Methods: A total 988 cores from 242 specimens corresponding to 224 patients diagnosed between 2008 and 2009 were examined. Each core was examined for the presence of normal glands, percentage of tumor involvement, biomarker status, and diagnostic adequacy. Results: Absence of normal glands was found on 61/242 specimens (25%). Of these, expression of ER, PR and HER2 was seen in 44 (72%), 28 (46%), and 21 specimens (35%) respectively. Negative staining for ER, PR and HER2 was observed in 7 specimens (12%). A total of 148 cores (15%) showed absence of tumor and 275 cores (28%) had <25% of tumor in them. 18 cores (2%) were insufficient for diagnosis due to either scant tumor present or crush artifact present. Conclusions: Although the presence of internal control glands is optimal, its presence may be unnecessary if proper IHC batch run controls are utilized and histologic/IHC concordance is performed. Tumor histology and IHC profile concordance is imperative specially in triple negative cases. The impact on patient health care of an “receptor uninterpretable” biopsy is yet to be determined, but likely would include assessment of the delay in care due to a repeat biopsy with procurement of additional tissue, additional heath care costs, and anxiety to the patient. Adequacy check using frozen section could be done to assess for the presence of tumor during the procedure.