Accuracy of frozen section diagnoses of breast lesions after introduction of a national programme in mammographic screening

Aims: By introducing mammography screening programmes, the size of the dete cted breast lesions became smaller and the histopathological interpretation problems greater, The study's aim was to analyse the risks and possible li mitations of the frozen section method. Methods and results: Frozen section consultations of breast lesions (n = 55 9) 2 years before and 6 years after launching a national mammographic scree ning programme in 1992 were evaluated in regard of the benign/malignant rat io, tumour size, preoperative frozen section results and final permanent se ction diagnoses, The breast frozen section examinations of 1990 compared wi th those from 1998 declined from 70.7% (299/423) to 62.2% (260/418) (P < 0. 01), the benign/malignant ratio from 1.09 to 0.54 (P < 0.0001), the rate of the conclusive, correct frozen section diagnoses from 96.3'%, to 91.9% (P < 0.03). The sensitivity dropped from 92.3% to 87.6%, the negative predicti ve value from 95.7% to 88.3%, whereas the negative likelihood ratio rose fr om 0.08 to 0.12, The 'smail' (<less than or equal to> 10 mm) invasive breas t carcinomas increased from 14.2% to 22.3% (P < 0.01) and the 'in situ' car cinomas from 2.1% to 6.6% (P < 0.05). Conclusions: The declining sizes of breast tumours (less than or equal to 1 0 mm), especially from radiologically detected lesions and sometimes withou t a macroscopic correlate, create new limitations and changing indications in the histopathological interpretation. Considering the performance of new diagnostic methods (i.e. large core needle biopsies), frozen sections of s urgical specimens should not be the primary diagnostic procedure for breast lesions and should be performed only after other preoperative methods have failed.