INTRAOPERATIVE CYTOLOGY IN BREAST-CANCER DIAGNOSIS - COMPARISON BETWEEN CYTOLOGIC AND FROZEN-SECTION TECHNIQUES

The diagnostic accuracy of frozen section (FS) examination and intraop erative cytology (IOC) has been compared in two different series of br east biopsies in which only one of the two methods has been used. The intraoperative results have been compared with the final histological diagnoses. Five-hundred-ten cases have been investigated by using FS o nly, and 407 by means of IOC The two series were comparable because th ey included the same pathologies, moreover we have subdivided each ser ies into four groups of pathologies to better evaluate the diagnostic accuracy of two methods. The total diagnostic accuracy of FS has been 93.13% vs. 95.33% of IOC. The value of diagnostic accuracy of FS and I OC in the four sub-groups substantially overlapped; there was only a l ittle difference in the group of ''various lesions'' in which the diag nostic accuracy of IOC was higher. No false positive has been observed in IOC. FS have produced one false positive (0.19%), whereas false ne gatives have amounted to 1.77% for IOC and to 1.72% for FS. Deferred d iagnoses have been 2.95% in IOC and 4.90% in FS examination. For both methods according to Galen and Gambino the following values have been calculated: sensitivity, specificity, efficiency, and predictive value . By comparing the data, the value of the cytological examination in t he intraoperative diagnoses results is evident mainly when the latter is coupled with the gross observation. Causes of diagnostic errors cle arly overlap both in IOC and in FS: (1) lesions with a fibroadenomatou s appearance can involve an overdiagnosis or an underdiagnosis; (2) lo w-grade lesions like tubular carcinomas or in situ lobular carcinomas can be interpreted as benign; (3) the differential diagnosis of intrad uctal lesions may be very difficult, and a conservative approach is th e best choice; and (4) infiltrating lobular carcinoma may be neglected both in FS and IOC The few disadvantages of the cytologic method are offset by its low cost, the wider sampling, the possibility of sparing tissue for further investigations (such as steroid receptors, cellula r kinetic, electron microscopy, and other biological studies) proved m ore useful in prognostic evaluation of breast cancer. (C) 1993 Wiley-L iss, Inc.