Background: Fine needle aspiration biopsy (FNAB) is widely used in the diagnosis of breast cancer. It is unknown whether, for palpable cancers, ultrasound-guided FNAB is more accurate than freehand FNAB, and practice varies between physicians, services and countries.
Methods: From consecutive women attending a major cancer centre in Florence, we prospectively recruited subjects who had a definitely palpable lump which was solid on ultrasound and suspicious of malignancy (n = 102). All subjects were investigated using both ultrasound-guided and freehand FNAB (one aspirate with each method). Radiologists skilled in both sampling techniques performed all clinical examinations and aspirations, and for each subject the same radiologist obtained both FNAB samples. Sequence of aspiration method was randomised. Cytological interpretation was blinded to method of sampling. Comparative sensitivity (and insufficiency) for FNAB using the two methods was calculated in all cancers (n = 97).
Results: Ultrasound-guided FNAB resulted in 13.6% (5-22%) less insufficient aspirates than freehand FNAB (chi2 = 7.58; p = 0.006). When insufficient aspirates are included and considered as negative, ultrasound-guided FNAB has a 14.6% (5.8-23%) or a 16.5% (7.6-25.4%) significantly better sensitivity than freehand FNAB (for cytology 3-5 positive or cytology 4-5 positive respectively). When insufficient aspirates are excluded from the analysis, ultrasound-guided FNAB has a 1.4% (-1.2 to 3.9%) or a 2.6% (-2.5 to 7.8%) higher sensitivity than freehand FNAB (for cytology 3-5 positive or cytology 4-5 positive respectively) but this difference in the sensitivity of the two methods is not statistically significant.
Conclusion: Our data suggest that ultrasound-guided FNAB has better sensitivity than freehand FNAB in palpable breast cancer, which is predominantly an effect of a significant reduction in insufficient aspirates, but in part an effect of 'upgrading' cytological classification of cancers.