From Acta Radiologica Diagnosis 1983, 24: 385-390.
STEREOTAXIC NEEDLE BIOPSY OF NON-PALPABLE BREAST LESIONS.
A clinical and radiologic follow-up.
G Svane, M.D., Department of Diagnostic Radiology, Karolinska Hospital, Stockholm, Sweden.
Non-palpable breast lesions that are revealed by mammary radiography can be dealt with in various ways (SVANE 1983, SVANE & SILFVERSWÄRD 1983). Needle biopsy cytology can provide guidance in the choice of treatment, and various methods have been evolved for such diagnostic examinations of non palpable lesions (MÜHLOW 1974, BOLMGREN et coll. 1977, NOVAK 1979). The present report deals with non-palpable breast lesions which were examined with a stereotaxic biopsy instrument (NORDENSTRÖM et coll. 1981) and were not excised within three months thereafter, but were followed up clinically and radiographically. The aim of the investigation was to reveal possible ‘false’ negative cytologic results.
Methods
The needle biopsy was in all cases preceded by routinely performed mammary radiography, with the compressed breast examined in cranio-caudal, latero-medial and oblique projections. The aberrant findings were roentgenologically classified as:
(1) Probably benign: a mass with distinct margin with or without calcifications, calcifications only (e.g. punctate, coarse densities) or an area of in creased attenuation without radiating structures.
(2) Probably malignant: an irregular mass, an area of increased attenuation with some radiating structures or a group of irregular microcalcifications.
(3) Malignancy of high probability: an irregular mass with spicules radiating from the periphery with or without calcifications. All lesions classified as malignancy of high probabilty were immediately operated upon. These cases are reported by SVANE & SILFVERSWÄRD.
Screw needle biopsy technique. The lesions were needled with the aid of the previously described stereotaxic screw needle biopsy instrument (NORDENSTRÖM et coIl. 1981). A Rotex Screw Needle Biopsy Instrument ® was used in all cases (NORDENSTRÖM 1980). The cellular material was smeared onto glass slides, which as a rule were air-dried and stained according to the May-Grünwald-Giemsa technique. They were then cytologically evaluated at the Department of Clinical Cytology, Karolinska Hospital.
Material
The stereotaxically examined material comprised a total of 527 consecutively detected nonpalpable lesions from mammary radiographies of 505 women. The age range of the women was 20 to 89 years, with a mean age of 54.2 and the largest age group being between 45 and 65 (Table 1). The original radiographic and stereotaxic examinations were made in the period August 1976 to May 1980.
Of these 527 lesions, 332 were stereotaxically identified and submitted to screw needle biopsy but were not excised, or were excised more than 3 months after the biopsy, and 74 could not be identified for biopsy at the stereotaxic examination. The 406 lesions observed on radiography of the breast comprise the material for the present investigation. At the preceding radiography, 375 of these 406 lesions were roentgenologically regarded as probably benign and 31 as probably malignant. Twenty-nine of the probably malignant lesions were reassessed as probably benign at the stereotaxic examination. The remaining 2 lesions were still regarded as probably malignant but excision was not performed despite recommendation. The remaining 121 lesions (114 patients) were those already mentioned as being excised within 3 months of screw needle biopsy (SVANE & SILFVERSWÄRD). The scheme of management of the patients is surveyed in Fig. 1.
The 317 patients with lesions from which cellular material was obtained by stereotaxic needle biopsy and the 74 patients, who stereoradiographically proved to have no lesions were followed up for periods ranging from 2 to 56 months. The length of follow-up was largely dependent on the clinical course and the degree of malignancy suggested at the original mammary radiography, and also on observations at subsequent radiographies. The purpose of the clinical and radiographic surveillance was to reveal possible “false” negative cytologic results.
Results
The 332 lesions which were identified in the breasts at stereotaxic screw needle biopsy are subgrouped in Fig. 2. Of the 9 patients not being followed up (a), 5 died (of unrelated diseases) during the observation period, 3 left the hospital’s catchment area and one failed to attend for re-examination. Of the 31 lesions in subgroup (b), 18 proved to be cysts, from which fluid was aspirated and which thereafter disappeared or diminished appreciably in firmness and size. Five lesions consisted of normal lymph glands and 8 were cytologically considered to be fibroadenomas. The size of these 31 lesions, the largest radiographic diameter being measured, was 5 mm or less in four cases, while ten were 6-10 mm, eight 11-15 mm, six 16-20 mm and three larger than 20 mm.
Nine lesions (subgroup c) were excised more than 3 months after screw needle biopsy. The reasons for excision were enlargement at subsequent mammary radiographies (4 lesions) or that excision, for other reasons, was considered to be more appropriate than continued clinical follow-up. The cytologic and histopathologic findings in these 9 lesions are presented in Table 2, which also demonstrates the maximum roentgenographic diameter of the malignant lesions.
The radiographic report from 2 of the histopathologically malignant lesions stated probable malignancy, while 2 were regarded as probably benign. One of the first two lesions was excised after slightly more than 3 months, without further radiography, and the other after 7 months, because of enlargement at a radiographic follow-up. One of the two probably benign lesions was excised after 15 months, also because of enlargement at a follow-up radiography. The remaining histopathologically malignant lesion was smaller on films taken 6 months after the stereotaxic biopsy. After one and a half year, however, radiography showed within the same quadrant of the breast a lesion of malignancy of high probability and there was palpable thickening of tissue in this area. Conventional aspiration biopsy now yielded malignant cells. It was not possible to decide if the malignant tumor had arisen after the stereotaxic biopsy, or if the same lesion had been needled on both occasions. The stereotaxic investigation could thus have given a “false” negative cytologic diagnosis. All 5 of the histopathologically benign tumors (Table 2) had been classified at mammary radiography as probably benign and the stereotaxic screw needle biopsy had yielded benign cellular material.
At subsequent radiographies 120 lesions (subgroup d, Fig. 2) had diminished in size (56) or disappeared (64). The radiographic and cytologic diagnoses of these 120 lesions are shown in Table 3 together with the follow-up period and the diameter of the lesions. The 2 lesions which originally were considered to demonstrate atypical epithelium could no longer be found at subsequent radiographies.
In 146 lesions there were no changes in size or appearance during the follow-up period (subgroup e, Fig. 2). Data concerning these lesions are presented in Table 4. All 3 lesions with an atypical cytologic appearance were observed for 25 months after the initial mammary radiography.
Three patients failed to co-operate in the biopsy procedure, which therefore was incorrectly performed (subgroup f, Fig. 2).
The initial biopsy yielded insufficient material for diagnosis of 10 of the lesions (subgroup g, Fig. 2). Subsequent biopsy in 3 of them demonstrated benign epithelium. All of these patients were radiographically followed up until the observed area was considered not to differ from normal breast tissue or to contain a benign lesion. The observation periods were as follows: 12 months 2 lesions, 13-18 months 2 lesions, 19-24 months 3 lesions, 25-36 months 2 lesions, and more than 3 years in the remaining case. The radiographic assessment of all 10 lesions was probably benign. Three of them were less than 5 mm at their largest diameter, while four were 6-10 mm, two 11-15 mm and one 16-20 mm.
In screw needle biopsy of 4 well defined lesions the needle displaced the target tissue and the yield was non-representative (subgroup h, Fig. 2). All 4 biopsies were done at the beginning of the examination period and the lesions presented firm resistance to the needle. The largest roentgenographic diameters were 3, 8, 15 and 20 mm, respectively. They were radiographically followed up for 7, 9, 21 and 25 months without discernible changes in the lesions. With increasing experience of the biopsy technique, needling of such lesions ceased to be a problem. It is possible to advance the screw needle carefully into the lesion while constantly rotating the needle in both directions. In this way the target does not deviate, even if it offers firm resistance. The 74 lesions in which stereotaxic examination could not confirm the radiographic observations are presented in Fig. 3. In addition to the 2 lesions that proved to be abnormalities in the skin, there were 2 that could not be reached by the stereotaxic biopsy procedure. One of these latter cases consisted of calcifications located peripherally in the breast, and the other one was a possible recurrence in a small residue of breast tissue after radical mastectomy. Of the other 70 lesions not confirmed at stereotaxic examination, 68 were radiographically followed up and these examinations revealed a lesion in only 7 cases. In 4 of them the lesions were too diffuse to enable a representative puncture to be chosen. The other 3 were calcifications, in one case intravascular. The calcified lesions were not excised, but were observed for 24 to 27 months without any evidence of change in appearance.
Discussion
A cytologic diagnosis of a non-palpable breast lesion should be as significant as that of a palpable lesion and provide guidance for the treatment of a radiographically detected aberration. If malignant cells are present in cellular material, surgery can be planned as a curative measure, and not only as a diagnostic biopsy. Benign appearance of cellular material may also be helpful and sometimes an operation can be avoided if the radiographic report of the same lesion is “probably benign”. On the other hand, a misleading negative report from a cytologic examination of a malignant lesion can delay appropriate treatment. Although the risk of a ‘false’ negative cytologic diagnosis cannot be wholly eliminated, even with sensitive technique, such a diagnosis has been found in only 4 of the 323 lesions in the present series which were needled but not immediately excised. For 2 of these 4 lesions the cytologic report stated benign epithelium and for the other 2 atypical epithelium. Two of the 4 lesions were considered to be probably malignant at radiography and excision was suggested even if the cytologic examination of screw needle cellular material would demonstrate only benign epithelium. This recommendation was not followed. None of the other non-excised lesions enlarged during the observation period and 120 lesions either diminished appreciably or disappeared. if these tumors had been malignant, the length of follow-up period would have sufficed in many cases to demonstrate this by roentgenographic expansion. Only 16.1 per cent of these lesions were observed for a year or less. The volume doubling time of malignant tumors has been reported as ranging from 42 days to 406 days (LUNDGREN 1977). In the absence of enlargement, the benign cellular material was presumably representative of the majority of the lesions.
Among the 74 radiographically demonstrated lesions which were not identified at the immediate stereotaxic examination, only 2 were found at a subsequent radiography to be of a type suitable for screw needle biopsy. These 2 calcified lesions were not confirmed at the stereotaxic examination, because a new film-screen system was used in the preceding mammary radiography, thus giving a higher film quality than in the stereotaxic examination, in which the new system could not be concomitantly introduced.
As with palpable breast lesions, however, the results from all diagnostic procedures must be collectively considered, i.e. radiographically as well as cytologically. The cellular yield must also be quantitatively adequate for cytologic assessment. In this material the stereotaxic screw needle biopsy technique has been used to support the roentgenologic assessment of the lesions regarded as ‘probably benign’. These lesions have according to previous routines been followed up by subsequent mammary radiographies every 3 to 6 months, instead of excision. Two of these lesions have during the follow-up period proven to be malignant, that is 0.6 per cent. Two additional histopathologically malignant tumors were excised during the follow-up period but these were roentgenologically regarded as probably malignant.
Combined consideration of the mammary radiographic and cytologic reports from the lesions regarded as benign, demonstrated an accuracy sufficient to permit reduction of the number of subsequent radiographies.
SUMMARY
A stereotaxic instrument has been evolved and is now routinely used for screw needle biopsy of non-palpable lesions of the breast detected at mammary radiography. A follow-up is presented of 323 such lesions which were not excised within 3 months of the initial radiography and biopsy. With a combination of results from radiographic and cytologic examinations of cellular material from stereotaxic biopsy, the incidence of “false” negative results was less than one per cent. The biopsy method can therefore be recommended for the investigation of non-palpable lesions of the breast revealed at mammary radiography.
REFERENCES
BOLMGREN J., JACOBSON B. and NORDENSTRÖM B.: Stereotaxic instrument for needle biopsy of the mamma. Amer J. Roentgenol. 129 (1977), 121.
LUNDGREN B.: Observations on growth rate of breast carcinomas and its possible implications for lead time. Cancer 40 (1977), 1722.
MÜHLOW A.: A device for precision needle biopsy of the breast at mammography. Amer. J.Roentgenol. 121 (1974), 843.
NORDENSTRÖM B.: Transthoracic needle biopsy. In: Percutaneous biopsy and therapeutic vascular conclusions, p.11. International Symposium, Munchen 1979.
Edited by H. Anacker, U. Gullotta and N. Rupp. Georg Thieme Verlag, Stuttgart, New York 1980.
RYDEN H. and SVANE G.: Breast. In: Percutaneous needle biopsy. Chapter 5, p.43. Edited by J. Zornoza. Williams & Wilkins, Baltimore, London 1981.
NOVAK R.: Position-controlled needle aspiration biopsy at mammography. Fortschr. Röntgenstr. 131(1979), 659
SVANE G.: A stereotaxic technique for preoperative marking of non-palpable breast lesions. Acta radiol. Diagnosis 24 (1983), 145.
SILFVERSWÄRD C.: Stereotaxic needle biopsy of non-palpable breast lesions. Cytologic and histopathologic findings. Acta radiol. Diagnosis 24 (1983), 283.
NB! Figures and tables are not shown here. This is a reference to Acta Radiologica Diagnosis 1983, 24:385-390.
