Accuracy of preoperative 11G vacuum-assisted core needle biopsy in determining histological type and molecular subtype in breast cancer

Abstract

Objective To assess the accuracy of histological type and molecular subtype observed in preoperative 11-gauge vacuum-assisted core needle biopsy(VACNB) specimens in breast cancer. Methods Patients diagnosed by preoperative 11-gauge VACNB and received subsequent open excisional biopsy (OEB) from Mar 1st 2014 to Mar 31st 2015 were included. Kappa testing was used to test the concordance rate of histological type, estrogen receptor(ER), progesterone receptor(PR), human epidermal growth factor 2(Her-2), Ki-67 and molecular subgroups between VACNB and paired OEB specimens. ER, PgR, Her-2, and Ki-67 were determined by immunohistochemistry (IHC). Patients with Her-2 IHC (+ + ) were further examined by FISH. Molecular subtypes were classified as follows: LuminalA, LuminalB, Triple Negative, and Her-2 positive. Results There were 36 patients analyzed(32 of them had invasive breast cancer). Between VACNB and paired OEB specimens, concordance rate of histological type, ER, PR, Her-2, Ki-67 and molecular group were 94.4%(κ=0.934), 96.9%(κ=0.904), 87.5%(κ=0.710), 100%(κ=1.000), 84.4%(κ=0.570), 78.1%(κ=0.621). No significant difference was detected in the expression of ER, PR and Ki-67 between VACNB and OEB specimens according to paired t-test results. Concordance rate of each molecular subtype between VACNB and OEB specimens were 100% for Her-2 positive subtype, 94.1% for LuminalB subtype, 50% for LuminalA, and 33.3% for TNBC. When the threshold for ER/PR positivity was upgraded from ≥1% to ≥10% and Ki-67 cutoff value to≥20%, the concordance rate for ER, PR, Ki-67 and molecular subtype reached to 100%, 93.8%, 87.5%, 81.3%. Conclusions 11 G vacuum-assisted core needle biopsy was accurate in determining histological type and molecular subtype in breast cancer. Key words: Breast neoplasm; Vacuum-assisted biopsy; Core needle biopsy; Breast subtypes; Concordance rate