The decision about whether to operate on patients with screen-detected mammographic abnormalities involves the correlation of clinical and radiological data and findings from needle aspiration cytology (FNAC) and/or needle core biopsy (NCB). This is best achieved in multidisciplinary meetings where the clinician, radiologist and pathologist (triple assessment) discuss these findings and reach a consensus on the appropriate management of each patient following pre-defined protocols.

Until recently, needle aspiration was the more widely used technique but core biopsy is being used increasingly. There has been much discussion about the relative merits and disadvantages of the two methods.

Core biopsy has several advantages. It is possible to distinguish in situ from invasive carcinomas although, not surprisingly, the technique has greater positive than negative predictive value as the invasive component of a tumor may not always be included in the biopsy. It is easier to diagnose carcinomas with low grade cytological features which are difficult to recognise without architectural interpretation. Specific benign diagnoses can be made and this allows better correlation of clinical, radiological and histological features. Another major advantage is that needle biopsies can be subjected to specimen radiography to ensure that the mammographic abnormality has been sampled. If the relevant calcification is included in the biopsy and is clearly associated with a benign process then an unnecessary operation is avoided.

On the other hand, fine needle aspiration is quicker to perform, does not require local anaesthetic and consequently uses less clinic time. Multiple passes with a needle can increase diagnostic accuracy with both techniques (FNAC and NCB) but is easier to perform with FNAC. Small and impalpable lesions are also generally easier to localise, particularly if imaging is used but localisation of lesions with NCB has improved significantly in recent years. As FNAC is a quicker technique cytopathologists can provide diagnoses in clinics so that triple assessment can be completed in a single visit.

Most pathologists, however, find if easier to interpret NCB and consequently the standards of diagnosis are generally higher except where FNAC is performed in major cytopathology centres.

It is clear that FNAC and NCB are complementary techniques in arriving at a non-operative diagnosis. The efficacy of both methods, however, is heavily dependent on the skill and experience of the operator who is rarely a pathologist, particularly in the case of needle core biopsy.

From "European Guidelines for Quality Assurance in Mammography Screening" 2^nd edition, June 1996. A downloadable file can be found at the site of the European commission (Coming from the main site, first choose 'Cancer' then 'Publications'): http://europa.eu.int/comm/dg05/index_en.asp

The results of FNAC are reported according to five categories:

1. Crush, when too much pressure is used during smearing.
2. Drying, when dry smears are allowed to dry too slowly or when wet-fixed smears have been allowed to dry out before fixation.
3. Tick smears, when an overlay of blood, protein-rich fluid or cells obscurs the picture, making assessment impossible.

1. Nuclear pleomorphism
2. Some loss of cellular cohesion
3. Nuclear and cytoplasmic changes resulting from, for example, hormonal influence or treatment effects.

1. The specimen is scanty, poorly preserved or poorly prepared, but some cells with features of malignancy are present.
2. The sample may show some malignant features without overt malignant cells present. The degree of abnormality should be more severe than in the previous C3 category.
3. The sample has an overall benign pattern but with occasional cells showing distinct malignant features.

For the purposes of data recording and quality assurance in breast screening programmes, it is recommended that needle core biopsies are classified on a 5 point scale in a similar fashion to cytological specimens. Some teams may wish to merge categories B3 and B4 as both indicate the need for further action.

It needs to be emphasised, however, that the categories are not the same as the five cytology categories and have different clinical inferences. It is essential that the histological appearances in NCB are compared with clinical and radiological findings in order to ensure that the biopsy is representative.

            An internal routine audit on the performance of FNAC of breast lesions was initiated in the department of Pathology of the University Hospital Tivoli from October 1995.
The results of 556 FNAC were reported according to the original classification of Wells et al. (1) and recently published in the European Guidelines for Quality Assurance in Mammography Screening (2). The aspirates are performed by two experienced gynaecologists ("senologists") and three radiologists specially trained for breast pathology. The FNAC are received alcohol-fixed and stained with Papanicolaou. All FNAC are examined by both a cytopathologist and a pathologist, a third reading is systematically done by the pathologist who is in charge of the weekly clinical meeting. During this meeting, the clinical and cyto-histological characteristics of the individual cases as well as the results of breast imaging are discussed by a multidisciplinary team to define a comprehensive management strategy of the patient. In Table I, the performances of the CHU Tivoli are compared to the FNAC standards suggested by EC guidelines (2).

In general, the results appear reasonably good but the sensitivity was too low (46% versus >60%) and the rate of inadequate FNAC in case of cancer higher than the EC standards (19% versus <10%). The performances slowly improved with time, if the three years periods are separately considered (Table II: absolute sensitivity from 43% to 57% respectively for the first and third periods). Nevertheless, the rate of inadequate FNAC in cancer cases remains high (17% for the third period).

The analysis of the results of FNAC in cancer cases is easier if absolute numbers are considered (Table III).

The unsatisfactory performances are caused by many of FNAC classified as suspicious for malignancy (C4: 39 cases) in case of cancer. We reviewed 36 out of the 39 cases considered as C4. Twenty-one samples are scanty, poorly preserved or hemorragic but some cells with features of malignancy were present. In 6 cases, the FNAC showed some malignant features without overt malignant cells. The 9 remaining samples were reclassified C5 after revision. This review shows that, in our experience, the factor "aspirator" is more determinant on the quality of FNAC than the factor "reader".

In conclusion, this study demonstrates the interest of an internal audit in the evaluation of the performance of FNAC in routine practice. The audit is successful in identifying the weak points of the technique that would have otherwise been obscured by the overall performance of the multidisciplinary team.

            Only 98 NBC were performed during the three-year period; the majority in 1998. A large proportion of the targeted lesions were smaller than 1.5 cm. Sonography and palpation, when the abnormality could be palpated, guided the NCB sampling for many patients. Two or three cores per case were obtained from 18 or 14 gauge needle and high-speed biopsy gun Bip â . NCB histologic findings were classified according to ECWGBSP guidelines and compared to FNAC performance for the same period.

The performance of NCB in terms of absolute sensitivity (the number of carcinomas in category B5 expressed as a percentage of the total number of carcinomas sampled) appears better than the results obtained with FNAC. This can be explained by the low rate of cases (1%) found in B4 category (suspicious for malignancy). In our experience, the samples obtained from NCB are of better quality than those of the aspirates and allows a more accurate diagnosis. In this preliminary study, the rate of inadequate NCB remains high, comparable to FNAC. A gain in experience of the samplers should improve the performance and diagnostic accuracy of NCB. Technical equipment also have a definitive and important impact on the overall results in using NCB for diagnostic purpose (3).

1) Wells C, Ellis I, Zakhour H, Wilson A. Guidelines for cytology procedures and reporting on fine needle aspirates of the breast. Cytopathology 1994; 5:316-334.

2) EC Working Group on Breast Screening Pathology. Cytopathology Guidelines in European Guidelines for Quality Assurance in Mammography Screening. 2nd edition Europe against Cancer; 1996.

3) Rosen PP. Role of cytology and needle biopsy in the diagnosis of breast cancer. In Rosen's Breast Pathology, chapt 48, Lippincott-Raven, 1996.