Image guided breast biopsy--technical advances.

Abstract

where appropriate, needle biopsy. Management examination is critical for some types of lesion. There decisions for non-palpable lesions are made on the remain, however, some types of mammographic basis of the imaging work-up and the results of abnormality, such as low or intermediate suspicion imaging guided needle biopsy. This non-operative microcalcifications and localized areas of architecapproach for confirming the diagnosis is of benefit tural distortion, where imaging guided CB may not both to patients and to the Health Service because give a definitive diagnosis or may demonstrate areas it reduces the number of diagnostic surgical excision of atypical ductal hyperplasia. In a proportion of biopsies for benign conditions and enables a definisuch cases, full histological examination of surgically tive diagnosis of malignancy to be made for patients excised tissue shows either non-invasive or invasive with breast cancer. Patients with breast cancer can carcinoma. One of the major advantages of CB over thus be offered effective pre-operative counselling FNAC is that unequivocal histological evidence of and definitive surgery can be planned, often avoiding invasive tumour may be demonstrated. In a prothe need for multiple operations. Quality targets for portion of cases, however, particularly where the sole both benign surgical biopsy rates and pre-operative mammographic abnormality is microcalcification, diagnosis rates for lesions detected in the National CB may fail to detect the presence of invasive tumour Health Service Breast Screening Programme within an area of ductal carcinoma in situ. This is (NHSBSP) are set in the published surgery and significant in clinical practice because treatment for radiology quality assurance guidelines. Although invasive cancer in most centres will involve axillary high benign surgical biopsy rates are not a feature surgery. Recent technical developments have made it of the NHSBSP, few programmes have been able to possible to carry out imaging guided diagnostic permeet the target standard of 70% for a positive precutaneous excision of larger tissue specimens for operative diagnosis of screening detected cancers. histological examination from non-palpable lesions. Image guided breast biopsy is currently based The Mammotome vacuum biopsy system conon the use of fine needle aspiration cytology sists of a disposable biopsy probe and a re-usable (FNAC) or core biopsy (CB). Both techniques can drive unit [4]. The Mammotome can be used with be used with either ultrasound or stereotactic either dedicated prone stereotactic equipment or guidance. Stereotaxis is generally used for microultrasound but cannot at present be used with calcifications and very small soft tissue masses or conventional upright add-on stereotactic units. The areas of architectural distortion which are invisible biopsy probe is available in either 14 G or 11 G or difficult to see on ultrasound. Although good sizes, but the best results have been obtained with FNAC results have been achieved by some centres, 11 G size. Within the biopsy probe is a vacuum particularly where there is a specialist breast cytochannel and a rotating cutting cylinder. The biopsy pathologist available, ‘‘equivocal’’ or ‘‘suspicious’’ probe is first advanced so that the tip of the probe results in 20–30% of cases, false negative rates of is just distal to the lesion. Just proximal to the up to 10% and inadequate sample rates of up to piercing tip of the probe is an aperture through 20% have led many centres in the UK to use CB which tissue is drawn by the vacuum. When the instead of or as well as FNAC [1, 2]. A further tissue has been drawn into the sample chamber,