Our data show that axillary FNAC has moderate sensitivity (which varies according to selection criteria for the test) and consistently high specificity, is associated with low inadequacy and very few false positives. We estimate that its use would have improved triage to initial nodal procedure in about one quarter of our cases. If one accepts the premise that initial surgical staging of the axilla should be based on all information available through pre-operative diagnosis, then axillary FNAC should be adopted routinely into clinical practice.

FNAC and CNB were generally performed in different patients, thus our study reported indirect comparisons of these tests. Although FNAC performed well (except for relatively high inadequacy), CNB had significantly better performance based on measures of sensitivity, but this was associated with lower specificity for CNB relative to FNAC. Overall, CNB is the more reliable biopsy method for sonographically-visible lesions; where FNAC is used as the first-line test, inadequate or inconclusive FNAC can be largely resolved by using repeat sampling with CNB.

We calculate the positive predictive value (PPV) of abnormal (C3-5) FNAC, alone and in combination with clinical and imaging findings, based on a consecutive series of 2,334 subjects. The PPV of a C3, C4 or C5 report is 55.0%, 95.9% and 99.4%, respectively. C5 Cytology is highly predictive of malignancy (PPV=99.4-99.7%) except where imaging is negative or benign. When C4 cytology is associated with suspicious findings on imaging and/or palpation, its PPV increases to 98.5-98.7%. C3 is the least predictive of malignancy and even when associated with suspicious findings on imaging and/or palpation its PPV is 83.3% - C3 FNAC should therefore prompt pre-operative core biopsy. These data indicate that FNAB is still a useful test in breast diagnosis, and it may assist clinical decision-making as far as whether patients should progress to surgical management or should have further core biopsy before planning surgery.

In summary, peer review represents an important internal quality control in the evaluation and improvement of inter-observer agreement and of the functioning of the laboratory as a whole. Multi-head microscope sessions may improve particularly the reproducibility of borderline diagnoses and, above all, can be an important training contribution for cytologists.

The authors evaluate 213 consecutive breast cancer cases with positive fine-needle aspiration cytology. Cytologic smears were reviewed and classified according to a grading system. A correlation between cytologic grading and pathological stage (T and N category) was observed. Univariate analysis of 5-yr overall survival rate showed a significant negative association with prognosis only for G3 (90%) compared to G1 (72%) cases. Such prognostic correlation was no longer significant at multivariate (Cox) analysis adjusting for potential confounders such as T or N categories. The prognostic value of cytologic grading is limited and dependent on other classic prognostic indicators that are currently determined in breast cancer patients. Its practical value is negligible, as it does not improve the prognostic judgment.