Histologic-radiologic correlation of mammographically detected microcalcification in stereotactic core biopsies

Invasive recurrence after breast conserving treatment of ductal carcinoma in situ of the breast in the Netherlands: time trends and the association with tumour grade

BACKGROUND

The first aim of this study was to examine trends in the risk of ipsilateral invasive breast cancer (iIBC) after breast-conserving surgery (BCS) of ductal carcinoma in situ (DCIS). A second aim was to analyse the association between DCIS grade and the risk of iIBC following BCS.

PATIENTS AND METHODS

In this population-based, retrospective cohort study, the Netherlands Cancer Registry collected information on 25,719 women with DCIS diagnosed in the period 1989-2021 who underwent BCS. Of these 19,034 received adjuvant radiotherapy (RT). Kaplan-Meier analyses and Cox regression models were used.

RESULTS

A total of 1135 patients experienced iIBC. Ten-year cumulative incidence rates of iIBC for patients diagnosed in the periods 1989-1998, 1999-2008 and 2009-2021 undergoing BCS without RT, were 12.6%, 9.0% and 5.0% (P < 0.001), respectively. For those undergoing BCS with RT these figures were 5.7%, 3.7% and 2.2%, respectively (P < 0.001). In the multivariable analyses, DCIS grade was not associated with the risk of iIBC.

CONCLUSION

Since 1989 the risk of iIBC has decreased substantially and has become even lower than the risk of invasive contralateral breast cancer. No significant association of DCIS grade with iIBC was found, stressing the need for more powerful prognostic factors to guide the treatment of DCIS.

Correlative Detection of Isolated Single and Multi-Cellular Calcifications in the Internal Elastic Lamina of Human Coronary Artery Samples

Histopathology protocols often require sectioning and processing of numerous microscopy slides to survey a sample. Trade-offs between workload and sampling density means that small features can be missed. Aiming to reduce the workload of routine histology protocols and the concern over missed pathology in skipped sections, we developed a prototype x-ray tomographic scanner dedicated to rapid scouting and identification of regions of interest in pathology specimens, thereby allowing targeted histopathology analysis to replace blanket searches. In coronary artery samples of a deceased HIV patient, the scanner, called Tomopath, obtained depth-resolved cross-sectional images at 15 µm resolution in a 15-minute scan, which guided the subsequent histological sectioning and microscopy. When compared to a commercial tabletop micro-CT scanner, the prototype provided several-fold contrast-to-noise ratio in 1/11^th the scan time. Correlated tomographic and histological images revealed two types of micro calcifications: scattered loose calcifications typically found in atherosclerotic lesions; isolated focal calcifications in one or several cells in the internal elastic lamina and occasionally in the tunica media, which we speculate were the initiation of medial calcification linked to kidney disease, but rarely detected at this early stage due to their similarity to particle contaminants introduced during histological processing, if not for the evidence from the tomography scan prior to sectioning. Thus, in addition to its utility as a scouting tool, in this study it provided complementary information to histological microscopy. Overall, the prototype scanner represents a step toward a dedicated scouting and complementary imaging tool for routine use in pathology labs.

Microcalcifications of the breast: a mammographic-histologic correlation study using a newly designed Path/Rad Tissue Tray

The introduction of screening mammography has brought about a greater knowledge of early breast cancer characteristics. These improvements have led to a reduction in size of suspicious lesions and a shift from surgical to image-guided core needle biopsies (CNBs). Establishing correlation between histologic and imaging findings is required for accurate diagnosis. Currently, there are no standardized multidisciplinary protocols for evaluating such lesions. We correlated histologic and radiologic findings in mammographically detectable calcified lesions in CNBs using specially designed Path/Rad Tissue Trays (patent pending, University of Kansas). Evidence of calcification was analyzed in 440 with and without the use of tissue trays. After mammographic identification of the lesion, CNBs are harvested, placed in tissue trays, and x-rayed to confirm sampling of the lesion. Images of CNBs with calcifications are marked by the radiologists and sent to the pathologist along with the biopsies. Trays with CNBs are then placed into cassettes and sent to the laboratory where they are embedded without disturbing orientation. Identification and localization of targeted microcalcifications were accomplished by radiologists and pathologists in 68 of 71 cases when using the tissue trays compared with 292 of 369 without tissue trays. Confirmation of microcalcifications was accomplished after deeper sectioning into tissue blocks from discordant cases. In conclusion, a systematic approach is recommended to standardize reporting of calcifications. The use of Path/Rad Tissue Trays has created a level of concordance between pathologists and radiologists that previously did no exist. It improved diagnostic reliability, encouraged communication between pathologists and radiologists, and minimized false diagnoses and/or delays in cancer diagnosis.

Raman spectroscopy: a real-time tool for identifying microcalcifications during stereotactic breast core needle biopsies

Microcalcifications are an early mammographic sign of breast cancer and a target for stereotactic breast needle biopsy. We present here a Raman spectroscopic tool for detecting microcalcifications in breast tissue based on their chemical composition. We collected ex vivo Raman spectra from 159 tissue sites in fresh stereotactic breast needle biopsies from 33 patients, including 54 normal sites, 75 lesions with microcalcifications and 30 lesions without microcalcifications. Application of our Raman technique resulted in a positive predictive value of 97% for detecting microcalcifications. This study shows that Raman spectroscopy has the potential to detect microcalcifications during stereotactic breast core biopsies and provide real-time feedback to radiologists, thus reducing non-diagnostic and false negative biopsies.

Update on percutaneous needle biopsy of nonmalignant breast lesions

Certain nonmalignant lesions encountered on percutaneous breast biopsies pose dilemmas with regard to the most appropriate clinical management subsequent to needle biopsy (ie, surgical excision vs. follow-up). These lesions include columnar cell lesions, atypical ductal hyperplasia, lobular neoplasia, papillary lesions, radial scars, fibroepithelial lesions, and mucocele-like lesions. As minimally invasive diagnostic procedures are now standard it is more important than ever to be aware of the limitations of percutaneous biopsy, particularly with regard to apparently benign lesions because of the risk that the radiologically detected lesion may harbor malignant disease not represented in the biopsy specimen. This underscores the importance of radiologic-pathologic correlation. Increasingly, radiologists are adopting vacuum-assisted devices using larger gauge needles. The changing practices among radiologists are reflected in recent studies which have enriched the literature. In addition, magnetic resonance imaging is being used more frequently in breast imaging, resulting in pathologists more often encountering benign biopsies with uncertain imaging correlation. These changes prompted evaluation of the recent literature and its possible effect on management concerns. This review focuses on management issues following the diagnosis of nonmalignant lesions diagnosed on percutaneous breast biopsy and highlights imaging terms commonly used in breast radiology reports to facilitate accurate radiologic-pathologic correlation.

Segregation of radiographic calcifications in stereotactic core biopsies of breast: is it necessary?

Stereotactic-needle core biopsy (SNCB) is increasingly being used for the evaluation of mammographic calcifications. Radiography of SNCB specimens is essential to confirm the presence of calcifications within the biopsy material. To aid and direct the pathologist, it has been recommended that SNCBs be separated into those with and without radiographic calcifications and separately embedded. However, the utility of this separation to the pathologist has not been established. We reviewed 80 consecutive 11 gauge vacuum-assisted SNCB procedures performed for mammographic calcifications. The core biopsies were separated by the radiologist into those with and without radiographic calcifications ("calcs" and "no calcs"). Twenty-nine of 80 (36%) of the "calcs" cores were atypical or malignant, while 23 of 80 (29%) of the "no calcs" cores were atypical or malignant (chi(2) = 0.63, p = NS). The same diagnosis was rendered in the "calcs" and "no calcs" specimens in 61/80 cases (76%). Two cases of ductal carcinoma in situ, four cases of atypical ductal hyperplasia and 13 cases of fibroadenoma were diagnosed in the "calcs" cores only. However, in all cases where the pathologic lesion was seen in the "calcs" core only, the pathologic lesion was present on initial H&E levels and would have been diagnosed even in the absence of core segregation. Deeper sections were deemed necessary in seven of the 80 cases. No change in diagnosis was made on the basis of these deeper sections, even in the cases where histologic calcifications appeared on deeper sections. Separate embedding of SNCBs into those with and without radiographic calcifications does not appear to be of great utility to the pathologist. Equal attention should be given to all cores in the setting of SNCBs for mammographic calcifications.

Intermediate to highly suspicious calcification in breast lesions: a radio-pathologic correlation

Breast calcification is an important feature in the radiological assessment of breast lesions. There are well established diagnostic criteria basing on the morphology and distribution of the calcifications radiologically with recommendation protocols. Pathologically, calcifications in breast lesions are of dystrophic type, and may occur in either the secretory materials or necrotic debris, with inflammation and osteopontin being plausible mediators. Detection of calcium phosphate (hydroyapaptite) is considerably easier than calcium oxalate. Radiologically amorphous calcification represents a borderline type of calcification, and occurs in both benign and malignant (low grade) lesions, and warrants careful follow up and investigation. Clustering of calcification alone may not be an accurate predictor for malignancy, but when there are associated features like pleomorphism, branching, architectural distortion, and associated mass or density, the predictive value for malignant increases. Adequate sampling of calcification in the biopsy is crucial in the management of patients; in general, needle core biopsy or mammotome biopsy achieve satisfactory calcification retrieval. In a benign biopsy that fails to identify the calcifications visible in the mammography, further evaluation or cutting of the histologic block is recommended to minimize the potential of a false negative investigation.

The significance of mammotome core biopsy specimens without radiographically identifiable microcalcification and their influence on surgical management—A retrospective review with histological correlation

The aim of this study is to assess core specimens which do not contain radiographically visible calcification at stereotactic vacuum assisted core biopsy (SVACB) of indeterminate microcalcification, to determine what influence they may have on the surgical management of patients with breast disease. Review was made of the core biopsy and surgical histology results of 104 SVACB biopsies of indeterminate microcalcification over a 26 month period. Cores were placed in separate pots; POT A for cores containing microcalcification and POT B for cores without radiographically visible microcalcification before being sent to histology. Of 104 biopsies, 25% contained B3-B5 pathology in POT B and at surgery this correlated with a higher grade of ductal carcinoma in situ (DCIS) and an increased likelihood of invasive disease. The presence of B3-B5 pathology in POT B itself however did not act as a strong indicator of radiological-histological size discrepancy in this study.

Breast Microcalcifications: Retrieval Failure at Prone Stereotactic Core and Vacuum Breast Biopsy—Frequency, Causes, and Outcome

PURPOSE

To retrospectively determine the frequency and causes of failure to retrieve microcalcifications in nonpalpable lesions, as judged on a radiograph of the specimen, and to determine outcome in patients with those lesions.

MATERIALS AND METHODS

Informed consent was obtained from each patient prior to biopsy. The institutional review board approved this HIPAA-compliant study and granted a waiver of informed consent. Retrospective review was performed of 1701 consecutive nonpalpable microcalcification lesions in 1511 women aged 29-92 years (median age, 54 years) who underwent percutaneous stereotactic biopsy on a prone biopsy table. Biopsy was successively performed with 14-gauge core, 14-gauge vacuum, and 11-gauge vacuum devices, with mild selection bias, and for each lesion, biopsy was performed with one device. Radiographs of the specimen were obtained to see whether microcalcifications were retrieved. Patient, mammographic, and biopsy variables were correlated with negative radiographs of the specimen. At repeat biopsy or mammographic follow-up, outcome was evaluated in patients with benign histologic results and negative radiographs of the specimen by using Fisher exact test P values.

RESULTS

Radiographs of the specimen were negative in 16% (30 of 182) of lesions at 14-gauge core biopsy, in 4% (four of 96) of lesions at 14-gauge vacuum biopsy, and in 1% (19 of 1423) of lesions at 11-gauge vacuum biopsy (P < .001). Substantial bleeding was a significant factor (P < .001) in failure to retrieve microcalcifications at only 11-gauge vacuum biopsy. Histologic results in 53 lesions with negative radiographs of the specimen were malignant (n = 6), indicated atypical hyperplasia (n = 6), or were benign (n = 41). Follow-up in patients with 40 benign lesions was performed with repeat biopsy (n = 17, with malignancy in three lesions) or mammography (n = 23) for 15-128 months (median, 70 months); one patient with one lesion was lost to follow-up.

CONCLUSION

Failure to retrieve microcalcifications was least common with 11-gauge directional vacuum-assisted biopsy and occurred in 1% (19 of 1423) of lesions. Cancer was missed in 8% (three of 40) of benign lesions in patients who were followed up.

Add-on Device for Stereotactic Core-Needle Breast Biopsy: How Many Biopsy Specimens Are Needed for a Reliable Diagnosis?

PURPOSE

To prospectively determine whether there is a minimum number of cores required for histopathologic diagnosis of mammographically detected nonpalpable breast lesions with an add-on 14-gauge stereotactic core-needle biopsy device.

MATERIALS AND METHODS

The study was approved by the ethics committee of the hospital; informed consent was obtained. Biopsy was performed in 197 patients with 205 lesions (97 masses, 108 microcalcifications). The first sample (from the center) was collected in container A; second and third samples (2 mm from center), in container B; and additional samples, in container C. Malignancies, atypical ductal hyperplasia (ADH), and radial scars were excised. Benign lesions were followed up mammographically (mean, 24 months). Strict sensitivity and working sensitivity were calculated separately. Stereotactic biopsy with diagnosis of a nonmalignant lesion that, after surgery, proved to be malignant was considered false-negative when strict sensitivity was calculated. Stereotactic biopsy with diagnosis of ADH or radial scar was considered true-positive if the findings at surgery corresponded to the results at biopsy or indicated malignancy and was considered false-positive if the findings at surgery were benign when working sensitivity was calculated. Sensitivity, specificity, and overall accuracy of stereotactic biopsy were determined for masses and microcalcifications in all three containers by using surgical samples and findings at mammographic follow-up as reference. At chi2 analysis, P < .05 was considered to indicate significant difference.

RESULTS

Strict sensitivity of the first sample was 77% (66 of 86) (90% [35 of 39] for masses, 66% [31 of 47] for microcalcifications). Results of the first sample were false-negative significantly more often in microcalcifications (n = 16) than in masses (n = 4) (P = .010). Combined results of containers A and B (ie, three samples) yielded higher strict sensitivity than those with first sample alone (95% [37 of 39] for masses [P = .196], 91% [43 of 47] for microcalcifications [P < .001]). With multiple samples, strict and working sensitivity were both 100% (39 of 39) for masses and 91% (43 of 47) and 98% (46 of 47), respectively, for microcalcifications. Four false-negative diagnoses (ADH, three cases; lesion with discordant mammographic and stereotactic biopsy findings, one case) were microcalcifications.

CONCLUSION

More than three samples are needed (a minimum number was not determined) for a histologic diagnosis of a mass lesion by using an add-on stereotactic biopsy device.

Best Practice No 179. Guidelines for breast needle core biopsy handling and reporting in breast screening assessment

Non-operative diagnosis has become the norm in breast disease assessment and, until relatively recently, fine needle aspiration cytology has been the sampling method of choice. The introduction of automated core biopsy guns in the mid 1990s led to the additional introduction of core biopsy in assessment units. This paper presents a summary of the guidance on handling and routine reporting of breast needle core biopsy specimens in the context of breast disease multidisciplinary assessment. This guidance has been produced by the UK National Coordinating Committee for Breast Screening Pathology and is endorsed by the European Commission working group on breast screening pathology.

Stereotactic core-needle biopsy of non-mass calcifications: outcome and accuracy at long-term follow-up

Objective

To determine, by means of long-term follow-up evaluation, the outcome and accuracy of stereotactic core-needle biopsy (SCNB) of non-mass calcifications observed at mammography, and to analyze the factors contributing to false-negative findings.

Materials and Methods

Using a 14-gauge needle, SCNB was performed in cases involving 271 non-mass calcified lesions observed at mammography in 267 patients aged 23-72 (mean, 47) years. We compared the SCNB results with those of long-term follow-up which included surgery, mammography performed for at least six months, and reference to Korean Cancer Registry listings. We investigated the retrieval rate for calcifications observed at specimen mammography and histologic evaluation, and determined the incidence rate of cancer, sensitivity, and the underestimation rate for SCNB. False-negative cases were evaluated in terms of their mammographic findings, the effect of the operators' experience, and the retrieval rate for calcifications.

Results

For specimen mammography and histologic evaluation of SCNB, the retrieval rate for calcifications was, respectively, 84% and 77%. At SCNB, 54 of 271 lesions (19.9%) were malignant [carcinoma in situ, 45/54 (83%)], 16 were borderline, and 201 were benign. SCNB showed that the incidence of cancer was 5.0% (6/120) in the benign mammographic category and 31.8% (48/151) in the malignant category. The findings revealed by immediate surgery and by long-term follow-up showed, respectively, that the sensitivity of SCNB was 90% and 82%. For borderline lesions, the underestimation rate was 10%. For false-negative cases, which were more frequent among the first ten cases we studied (p = 0.01), the most frequent mammographic finding was clustered amorphous calcifications. For true-negative and false-negative cases, the retrieval rate for calcifications was similar at specimen mammography (83% and 67%, respectively; p = 0.14) and histologic evaluation (79% and 75%, respectively; p = 0.47).

Conclusion

In this study group, most diagnosed cancers were in-situ lesions, and long-term follow-up showed that the sensitivity of SCNB was 82%. False-negative findings were frequent during the operators' learning period.

Expert opinion: Reporting needle core biopsies of breast carcinomas

Many breast carcinomas are now diagnosed in needle core biopsies, after either mammographic detection or symptomatic presentation. There is dispute, however, about the range of information that should be included in the diagnostic report of these small and possibly unrepresentative samples. Is it sufficient to simply report the presence of carcinoma, in situ or invasive? Or should the histopathologist give a more detailed report including features of prognostic and predictive significance? If so, what is the evidence that the further information is, first, of clinical benefit and, second, not unreliable because of sampling variability? To address the question "What should be included in reports of needle core biopsies of breast carcinomas?" contributions were invited from authors in the USA and the UK.

Issues in the interpretation of breast core biopsies

Core biopsies are now widely used for the nonoperative diagnosis of breast masses and microcalcifications and have replaced fine-needle aspiration (FNA) cytology for most lesions in many centers. In the United Kingdom, a scoring system of 5 reporting categories, B1-B5, has been adopted, which is to some extent similar to that used in the interpretation of breast FNA. This article is based on the practice at Charing Cross Hospital, London, which is a major regional breast screening and treatment center covering the West of London area; as well as on a thorough review of the contemporary literature. It begins by discussing issues related to the adoption of the technique and to handling core biopsies, followed by a brief presentation of the reporting categories. The article then deals with some commonly encountered diagnostic problems.

Stereotactic 11-gauge vacuum-assisted breast biopsy: a validation study

OBJECTIVE

The aim of our study was to determine the false-negative rate of stereotactic 11-gauge vacuum-assisted biopsy in a validation study of lesions that had subsequent surgical excision.

MATERIALS AND METHODS

Retrospective review was performed of 318 lesions that underwent stereotactic 11-gauge vacuum-assisted biopsy and subsequent surgical excision. A false-negative case was defined as a pathologically proven cancer in which stereotactic biopsy yielded benign results without atypia. Medical records, imaging studies, and histologic findings were reviewed.

RESULTS

False-negative findings were encountered at stereotactic 11-gauge vacuum-assisted biopsy in 3.3% (7/214) of pathologically proven cancers. False-negative findings occurred in 3.5% (4/115) of malignant calcification lesions versus 3.0% (3/99) of malignant masses (p = 1.0). The seven false-negative findings included five Breast Imaging Reporting and Data System (BI-RADS) category 5 lesions that yielded benign results at biopsy, one BI-RADS category 4 mass that benign breast tissue, and one BI-RADS category 4 cluster of calcifications in which no calcifications were retrieved. The false-negative rate was 10.0% (6/60) for radiologists who performed 15 or fewer previous stereotactic vacuum-assisted biopsy procedures versus 0.6% (1/154) for radiologists who performed more than 15 previous stereotactic vacuum-assisted biopsy procedures (p = 0.002).

CONCLUSION

Stereotactic 11-gauge vacuum-assisted biopsy had a false-negative rate of 3.3% that diminished to 0.6% with experience. All false-negative findings could be prospectively identified because of failure to sample calcifications or imaging-histologic discordance.

Histologic and radiographic analysis of ductal carcinoma in situ diagnosed using stereotactic incisional core breast biopsy

BACKGROUND

Stereotactic incisional core breast biopsy (SCBB) is a highly specific technique for diagnosing ductal carcinoma in situ (DCIS) in patients with suspicious mammographic microcalcifications. However, its sensitivity for excluding the presence of coexisting occult invasive disease in this setting is not fully established.

DESIGN

We correlated SCBB findings to subsequent lumpectomy/mastectomy (lx/mx) results in 122 cases of DCIS. In 29 of these cases, the SCBB showed microscopic invasion (n = 15) or foci that were suspicious for invasion (n = 14). Likelihood for invasive disease in subsequent lx/mx samples from each case then was compared with various parameters, including DCIS grade, extent and mammographic findings.

RESULTS

Overall, 13% of cases in which the SCBB showed DCIS only (i.e., without any evidence of invasion), had invasive disease in the subsequent excision. This finding was significantly correlated with DCIS grade (low: 0/26 [0%], intermediate: 2/31 [6%], high: 10/36 [28%], P <.001). Invasive lesions were usually small (nine T1a, one T1b, and two T1c) and typically present within more extensive fields of DCIS (no invasion: 1.5 cm DCIS size; invasion: 2.8 cm mean DCIS size, P =.01). This was reflected by greater extent of involvement in the SCBB (5/8 cases with invasion had >15 ducts involved, versus 4/23 with <15 ducts involved, P =.03). SCBB that were suspicious or positive for microinvasion demonstrated invasion in most subsequent excision (susp: 7/14 [50%], microinv: 11/15 [73%]), generally of significant extent (11/18 T(1b-c)).

CONCLUSIONS

1. Patients with SCBB showing high grade DCIS and DCIS suspicious or positive for microinvasion have a significant and high likelihood, respectively, of harboring occult invasive neoplasm. They should accordingly be carefully evaluated radiographically, and possibly with sentinel node biopsy to facilitate axillary staging. 2. Likelihood of occult invasion is correlated with overall DCIS size/extent.

Histological correlation of mammographically detected microcalcifications in stereotactic core biopsies

The aims of this study were to assess the value of specimen radiographs of stereotactic core biopsy, the usefulness of measuring size of calcifications on tissue sections, whether demonstration of calcifications in tissue sections alters the pathological diagnosis when specimen radiograph demonstrates calcifications, and to correlate these assessments with diagnostic outcome. A total of 301 core biopsies from 266 women with 274 mammographically suspicious areas of calcifications were examined. Core biopsies (five cores per procedure) were obtained stereotactically using a 14-gauge needle in an automated Biopty gun. Prior to processing of the tissue, 214 core biopsy specimens from 193 women with 197 lesions were radiographed. Of the 301 core biopsies, 56 (19%) were diagnosed as malignant, 15 (5%) were diagnosed as atypical ductal hyperplasia and 230 (76%) contained benign breast tissue. Of the core biopsies diagnosed as benign, 160 (70%) had specimen radiography prior to processing. Of these, 109 (69%) core biopsies showed calcifications on specimen radiographs. In 96 (88%) of these core biopsies, calcifications measuring > 100 microm were found on the initial tissue sections. In 11 (10%) further deeper sections were required to detect calcifications > 100 microm; however, this did not result in a change of the pathological diagnosis. Two of the 109 (1.8%) "benign" core biopsies, which contained tissue calcifications > 100 microm and at that time were considered representative of the mammographic lesion, have had a malignant outcome on clinical and mammographic follow-up ranging from 2.4 to 7.5 years. Of the 51 (31%) core biopsies where calcifications were not seen on specimen radiographs, histological calcifications were not found in 34 (67%) core biopsies, whereas in 17 (33%) core biopsies, calcifications measuring < 100 microm were found. All of these core biopsies were considered non-diagnostic and therefore not representative of the lesion targeted. Five (9.8%) of these cases had a malignant outcome with either immediate rebiopsy or excision. Accurate diagnosis of all mammographic lesions requires radiological-pathological correlation. This study shows that the presence of calcifications on the specimen radiograph and the demonstration of tissue calcifications > 100 microm are an essential and highly reliable part of core biopsy assessment for mammographically "suspicious" calcifications. Nevertheless, lesions with "highly suspicious" calcifications on mammography should be considered for excision even if the core biopsy diagnosis is benign and calcifications > 100 microm are present.

Does exhaustive search for microcalcifications improve diagnostic yield in stereotactic core needle breast biopsies?

Stereotactic core needle biopsy (SCNB) of the breast is a cost-effective alternative to needle localization biopsy for the diagnosis of mammographic calcifications. We questioned whether an exhaustive search for calcium in the small samples obtained in SCNB yields more diagnostic information than that obtained with examination of a standard number of sections. We retrospectively reviewed 168 specimens from 123 patients with mammographic calcifications, including cases in which radiographic suspicion ranged from low to high. Microcalcifications were identified on three initial levels in 112 specimens. Additional sections were examined in 50 specimens. The final diagnosis differed from the diagnosis based on three levels in 11/50 cases (22%). In 6/50 (12%), complete sectioning yielded a specific diagnosis. The increase in technical cost associated with the additional levels was 414% per case. We conclude that exhaustive searching for microcalcifications in SCNB yields a small increase in specific diagnostic information and a high technical cost. In individual cases, the additional information may be critical for appropriate patient management.

Improving the sensitivity of stereotactic core biopsy to diagnose ductal carcinoma in situ of the breast: a mathematical model

Stereotactic core biopsy (SCB) is performed on mammographically suspicious, non-palpable lesions of the breast. Reported sensitivities of SCB for the detection of ductal carcinoma in situ (DCIS) vary from 41% to 93%. We have developed a simple mathematical model to predict the probability of retrieving at least one diagnostic core from a focus of DCIS. We make recommendations of the number of samples needed for different sized areas of microcalcification. The sensitivity of SCB is affected by needle placement accuracy, diameter of the area of microcalcification (d), histological density of DCIS (x) (calculated as 7.5% by previous studies) and number of core samples (n) removed. The probability of achieving at least one representative core sufficient for diagnosis (P(core)) is defined as: P(core) = 1-(1 + p ([1- (x/100)]d - 1 ))n, where rho is the probability of a SCB accurately targeting the area of microcalcification. At least seven core samples should be removed in small foci (<5 mm) of DCIS to achieve a 0.75 probability of an accurate diagnosis. The probability of a diagnostic biopsy of larger areas of DCIS (>10 mm) is 0.95 when five cores are removed. This formula serves as an explanation to patients why SCB may fail to diagnose DCIS, and justifies the retrieval of more core samples to increase the probability of an accurate diagnosis and to reduce the chance of a non-representative core. In the absence of sufficient samples, a wire-guided open biopsy is necessary to exclude DCIS.

When have mammographic calcifications been adequately sampled at needle core biopsy?

AIMS

To determine if the number of flecks of calcification retrieved at stereotaxic core needle biopsy or the number of core samples obtained containing calcification are related to biopsy sensitivity, and to determine how many calcifications or cores containing calcification the radiologist should aim to retrieve when sampling mammographic microcalcification.

MATERIALS AND METHODS

A retrospective review was performed of core specimen radiographs from 57 consecutive patients who had stereotaxic core needle biopsies of impalpable malignant microcalcifications without an associated mammographic mass. The total number of calcifications retrieved and the numbers of cores containing calcification were correlated with findings at core and surgical histology.

RESULTS

Increasing retrieval of calcification elements visible on specimen radiography was associated with increasing sensitivity of the biopsy. Five or more flecks of calcium gave an absolute sensitivity of 100%. Increasing numbers of core samples obtained containing radiographically demonstrable calcification was also associated with increasing sensitivity. Three or more cores containing calcium resulted in a 100% absolute sensitivity for malignancy.

CONCLUSION

To ensure adequate sampling of calcification at core biopsy, an optimum of either three or more cores containing calcium or five or more flecks of calcium in total is required. Achieving this target ensures a high pre-operative diagnosis rate for malignant microcalcifications.Bagnall, M. J. C. (2000). Clinical Radiology 55, 548-553.