Reliability of prognostic factors in breast carcinoma determined by core needle biopsy

OBJECTIVE: The aim of this study was to evaluate the reliability of information obtained by core needle biopsy (CNB). METHODS: We studied 111 women (112 lesions) with breast cancer who underwent CNB and subsequent surgical excision. Six factors (histological type, nuclear grade, histological grade, estrogen receptor (ER) status, progesterone receptor (PR) status, and human epidermal growth factor receptor-2 (HER2) status) were evaluated in a blinded fashion at CNB and at surgical excision. RESULTS: The histological type at CNB correlated exactly with that of the excisional specimen in 83% (87/105) of the cases. Of the 45 in situ lesions at CNB, 16 (36%) were found to have invasive carcinoma at surgical excision. The difference between the specimens from CNB and those from surgery in terms of the absolute concordance rate and kappa statistic value were 61% with a fair kappa value (0.26) in the nuclear grade, 75% with a moderate kappa value (0.55) in the histological grade, 95% with an almost perfect kappa value (0.84) in ER, 88% with a substantial kappa value (0.70) in PR and 88% with a substantial kappa value (0.65) in HER2. Regarding the evaluation of nuclear and histological grades, a trend toward greater accuracy was observed when thicker specimens were used. CONCLUSIONS: CNB provided reliable information on the histological type of invasive carcinoma. It also evaluated ER, PR and HER2 (only in cases where the score was 3+) accurately in spite of the limited quantity of the specimen obtained with the thin (16-gauge) needle.