Percutaneous ultrasound- guided automated core biopsy is an alternative to surgical biopsy for the histological assessment of breast lesions [13
]. Frozen section examination of breast core biopsy specimens is an acceptable technique in the initial evaluation of suspect breast lesions [10
In our present analysis of 109 women, we performed 120 CNB. Out of the cases we obtained 59 frozen section analysis and found 2 false negative results yielding an underdiagnosis and overdiagnosing in 3.5% and 0%, respectively. Our reported data are in accordance with previous reports [10
]. In the early 1980s Gonzales et al [10
] compared the results on frozen sections of Tru-cut®
needle biopsies in 162 cases in a six year period. There were 20/103 (19.4%) false negative cases of carcinomas in frozen section analysis, one biopsy was considered positive in frozen section but permanent preparations revealed a very atypical intraductal papilloma, yielding a sensitivity and specificity of 77% and 86%, respectively. To our knowledge since then only one paper was published on the accuracy of frozen section analysis in needle biopsies of breast lesions: Mueller- Holzner et al. [11
] analysed in a retrospective study the results on frozen section analysis in 2619 cases over a 10 year period. Using a comparable procedure with an automated biopsy gun, they found 1276 malignant lesions. There were 7/1276 (0.5%) false negative cases in frozen section and 5/1276 (0.4%) false negative cases in paraffin section analysis of the CNB. Of note, they also found one false positive case in frozen sections and one in paraffin sections, yielding an overall sensitivity and specificity in frozen section analysis of 99.5% and 85.9%, respectively.
We aimed to find out some risk factors for the cases of false negative results, but we could not demonstrate any clinical or pathologic criteria, which were significantly related. Of note, the limitation of our study is beside the retrospective design, the relatively small cohort of patients for statistical analysis. But on the other hand we could not establish an independent predictor (e.g. tumor histology, tumor grade, tumor size, estrogen receptor content, progesterone receptor content, Her-2 over expression, age of the patients, bilateral disease or the lymph node status) for women with suspect breast lesions for whom the method of CNB and frozen section analysis could not be recommended. The reason for rereading the two false negative cases in frozen section analysis of the CNB was one mucinous carcinoma, which was found later in deeper paraffin section slides and a wrong orientation with folding the core biopsy specimens, respectively.
Based on data showing no sufficient relation between the number of cores and diagnostic accuracy we did not analyse the amount of tissue obtained by CNB in our database [15
Our study also has strengths, namely the CNB needle procedure was performed exclusively by three persons who had undergone dedicated training in CNB techniques and all frozen sections specimens were analysed by only two board-certified pathologists, specialized in gynaecologic pathology.
From the clinical point of view there is an interesting aspect in cases of malignancy. There is no significant difference according to the time interval between diagnosis by CNB and definitive treatment whether CNB was analysed by frozen section (13.1 days) or solely paraffin section (11.8 days). Taking this into account one can assume that it is possible to reduce the time interval for further one or two days. In this time interval our patients were staged according to a modified staging system for breast cancer including abdominal- and thorax computed tomography, radio nuclide bone scan, gynecologic examination and gynaecologic examination and assessment of serum tumor markers. Thereafter all women were scheduled for surgical therapy or neoadjuvant treatment.
From the critical point of view our procedure did not lead to faster definitive surgical care. With the knowledge of our data, we currently try to improve the procedure in our institution. Now most of the diagnostic metastatic tests are done after the surgery and we consequently aim to shorten the delay to definitive treatment.
In order to avoid false diagnostic cautions, upfront selection of the specimens is needed to identify those that are appropriate for frozen section examination. For example papillary lesions are better classified after multiple paraffin sections are carefully studied [16
]. Furthermore, limitations in calcified lesions are recognized due to geometry and histological heterogeneity. For microcalcifications this technique is not feasible and stereotactically- guided CNB is usually preferred since these lesions cannot usually be visualized by ultrasound [17