The role of pre‐operative diagnosis in breast cancer

In the last 20 years, the use of frozen-section under general anaesthesia has largely been replaced in the UK by other techniques for obtaining an accurate diagnosis prior to surgery. The benefits of pre-operative diagnosis in breast disease are well recognized and enable both clinician and patient to decide on a course of definitive treatment for malignant lesions, allowing one step surgery if appropriate. The reliance on frozen-section diagnosis for breast lesions, with its associated psychological trauma for the patient and inefficient planning of operating time and bed occupancy, has thus been rendered increasingly obsolete by the use of both needle biopsy and fine needle aspiration cytology (FNAC). The relative popularity of these two techniques has changed with time and geography. In the 1970s many groups in the UK favoured trucut biopsy as the technique of choice for pre-operative diagnosis, although elsewhere in Europe FNAC was widely utilized. However, by the mid to late 1980s, the ability of experienced operators to obtain samples from breast lesions using fine needles, through freehand or image guided aspirations, led to the acceptance of FNAC as the preferred diagnostic method in the UK when combined with clinical examination and mammography in a triple assessment. More recently, in the mid 1990s, the development of improved equipment for corecut biopsy has led those involved in screening programmes to reevaluate its role in the pre-operative diagnosis of impalpable lesions. Thus, at the present time, the debate has re-commenced about the optimum method for obtaining pre-operative diagnosis in breast lesions and whether needle core, FNAC or both should be used. Dahlstrom et al. have reported on a series of stereotactic core biopsies of mammographically suspicious lesions from 200 patients and comment on the diagnostic accuracy of this technique. In addition, these authors have assessed the precision with which stereotactic core biopsy can be used to make specific diagnoses, including histological grade and type of breast carcinoma. Fine needle aspiration cytology of breast lesions has become widely used with the advent of the National Health Service Breast Screening Programme (NHSBSP) and is simple, cheap and little equipment is required. However, the efficacy of FNAC relies heavily on the experience of both aspirator and pathologist and regular audit shows that the most experienced aspirators have the highest success rate and the lowest number of technically poor specimens; the inadequate rate can range from 9.8% to 45.9% from single experienced aspirators to inexperienced groups of clinicians. Other factors which influence the success rate of FNAC diagnosis include the size and cellularity of the lesion, but by adopting the triple approach to diagnosis, with independent FNAC, clinical and radiological evaluation, the sensitivity and specificity of FNAC can be extremely high. The sensitivity ranges from at least 75% to 96%, the specificity approaches 100% in most series and false-positive results are extremely rare. Thus, in the vast majority of published series, FNAC meets the minimum requirements suggested by the Cytology SubGroup of the National Co-ordinating Committee for Breast Screening Pathology. However, in some centres FNAC is still regarded with caution, for example in a large series of 7495 FNAC specimens with a sensitivity and specificity of 83.9% and 99.5%, respectively, Fessia et al. nevertheless surprisingly concluded that ‘frozensection diagnosis could be bypassed only in selected cases’. Other authors similarly maintain that FNAC assessment is insufficiently robust to allow definitive diagnosis of benign lesions due to an unacceptable high false negative rate, and feel that palpable lesions reported as benign cytologically should be excised, even with the use of the triple approach. However, some groups, ourselves included, are satisfied that lesions may be left ‘in situ’ if all specialities concur with a benign assessment. Core biopsy does however have the advantage of allowing definitive diagnosis of specific benign lesions, rather than the ‘benign’ (C2) diagnosis which FNAC assessment can provide, adding increased confidence in the decision not to excise these abnormalities. Whilst, as Dahlstrom et al. note, FNAC requires experience both in clinical and laboratory performance, core biopsy can be carried out and evaluated easily by histopathologists to whom haematoxylin and eosin Histopathology 1996, 28, 563–566