Nonpalpable breast lesions at biopsy. A detailed analysis of radiographic features

High-resolution 3D micro-CT imaging of breast microcalcifications: a preliminary analysis

BACKGROUND

Detection of microcalcifications on mammograms indicates the presence of breast lesion, and the shapes of the microcalcifications as seen by conventional mammography correlates with the probability of malignancy. This preliminary study evaluated the 3D shape of breast microcalcifications using micro-computed tomography (micro-CT) and compared the findings with those obtained using anatomopathological analysis.

METHODS

The study analyzed breast biopsy samples from 11 women with findings of suspicious microcalcifications on routine mammograms. The samples were imaged using a micro-CT (SkyScan 1076) at a resolution of 35 μm. Images were reconstructed using filtered back-projection and analyzed in 3D using surface rendering. The samples were subsequently analyzed by the pathology service. Reconstructed 3D images were compared with the corresponding histological slices.

RESULTS

Anatomopathological analysis showed that 5 of 11 patients had ductal breast carcinoma in situ. One patient was diagnosed with invasive ductal carcinoma.Individual object analysis was performed on 597 microcalcifications. Malignant microcalcifications tended to be thinner and to have a smaller volume and surface area, while their surface area-to-volume ratio was greater than that of benign microcalcifications. The structure model index values were the same for malignant and benign microcalcifications.

CONCLUSIONS

This is the first study to use micro-CT for quantitative 3D analysis of microcalcifications. This high-resolution imaging technique will be valuable for gaining a greater understanding of the morphologic characteristics of malignant and benign microcalcifications. The presence of many small microcalcifications can be an indication of malignancy. For the larger microcalcifications, 3D parameters confirmed the more irregular shape of malignant microcalcifications.

Findings of breast sonography in patients with foal asymmetric breast density on mammography

BACKGROUND

The imaging parameters that mandate further diagnostic workup in focal asymmetric breast densities are not clearly defined. To identify indications for further workup in Focal asymmetric breast densities (FABD) by doing ultrasonography.

METHODS

One-hundred women underwent breast ultrasonography after incidental discovery of FABD on mammograms. Mammograms and sonograms were evaluated for lesion location, associated calcifications, architectural distortion and change from previous examination when available.

RESULTS

Twenty three patients had abnormal sonographic findings and the site of sonographic abnormal findings was the same as the site of FABD on mammography. Sonographic findings were 7 focal increases in fibrous tissue, 5 ductal ectasias,4 simple cysts, complex cyst in one, 4 benign solid masses, one malignant solid mass and one with fibrous tissue at the site of pervious breast surgery. There was a significant relation between FABD in upper inner quadrant and normal sonography (p=0.036) and FABD in retroareolar region and ductal ectasia in sonography (p=0.002).

CONCLUSION

FABD usually present a benign etiology and can safely be managed by follow up. Sonography helps the physician do tissue diagnosis by detecting mass with features of possibly malignancy, in the women with negative physical examination.

Stereotactic and sonographic large-core biopsy of nonpalpable breast lesions

RATIONALE AND OBJECTIVES

To determine the diagnostic accuracy of stereotactically and sonographically guided core biopsy (CB) for the diagnosis of nonpalpable breast lesions.

MATERIALS AND METHODS

Twenty-two institutions enrolled 2,403 women who underwent imaging-guided fine needle aspiration followed by imaging-guided large-CB of nonpalpable breast abnormalities. All mammograms were reviewed for study eligibility by one of two breast imaging radiologists. The protocol for image-guided biopsy, using either ultrasound (USCB) or stereotactic (SCB) guidance, was standardized at all institutions and all biopsy specimens were over-read by one of three expert pathologists. Patients with atypical ductal hyperplasia (ADH), atypical lobular hyperplasia, or lobular neoplasia on CB underwent surgical excision. Those with negative CB but suspicious ("discordant") pre-biopsy mammography also underwent surgical excision. Patients having a negative CB that was concordant with the pre-biopsy mammography suspicion were assigned to follow-up mammography at 6, 12, and 24 months following CB.

RESULTS

A gold standard diagnosis based on definitive histopathologic diagnosis, mammography follow-up, or an imputed gold standard diagnosis was established for 1,681 patients. Of 310 cases with a gold standard diagnosis of invasive breast carcinoma, 261 (84.2%) were invasive carcinoma, 31 (10%) were ductal carcinoma in situ (DCIS), four (1.3%) were ADH, one (0.3%) was a non-breast cancer, and 13 (4.2%) were benign on CB. For 138 cases with a gold standard diagnosis of DCIS, 113 (81.9%) were DCIS, 20 (14.5%) were ADH, and five (3.6%) were benign on CB. For 57 cases (13 masses, 44 calcifications) with an initial CB diagnosis of ADH, atypical lobular hyperplasia or lobular neoplasia, 20 (35.1%) had a gold standard diagnosis of DCIS (4 masses, 16 calcifications) and four (7.0%) had a gold standard diagnosis of invasive cancer (4 calcifications). Of 144 cases (22 masses, 122 calcifications) with an initial CB diagnosis of DCIS, 31 (21.5%) had a gold standard diagnosis of invasive cancer (10 masses, 21 calcifications). The sensitivity, specificity and accuracy for CB by either imaging guidance method in this trial were .91, 1.00, and .98, respectively. The sensitivity, predictive value negative, and accuracy of CB for diagnosing masses (.96, .99, and .99, respectively) were significantly greater (P < .001) than for calcifications (.84, .94, and .96, respectively). The sensitivity (.89) of SCB for diagnosing all lesions was significantly lower (P = 0.029) than that of USCB (.97) because of the preponderance of calcifications biopsied by SCB versus USCB. There was no difference between USCB and SCB in sensitivity, predictive value negative, or accuracy for the diagnosis of masses (97.3, 98.9, and 99.2, respectively for USCB; 95.6, 98.5, and 98.9 respectively for SCB).

CONCLUSION

Percutaneous, imaged-guided core breast biopsy is an accurate diagnostic alternative to surgical biopsy in women with mammographically detected suspicious breast lesions.

Eliciting a terminology for mammographic calcifications

AIM

Two studies were carried out to establish, validate and assess descriptors for use in the differential diagnosis for mammographic calcifications.

METHODS

In Study 1, eleven radiologists were asked to 'think out loud' as they interpreted 20 sets of calcifications. Participants used 159 terms to describe calcifications. We used this data to design a scheme with 50 descriptors. In Study 2, ten radiologists used the scheme to describe 40 sets of calcifications. We assessed the capacity of the terms to discriminate between benign and malignant calcifications, testing them against radiologists' assessments of malignancy and follow-up data.

RESULTS

All descriptors were used by at least 5 radiologists. Five additional descriptors were required. With some exceptions, properties that discriminated between benign and malignant outcomes were highly correlated with radiologists' assessment of risk. Many descriptors have a fairly low sensitivity but high specificity.

CONCLUSIONS

Our data suggest that radiologists consider a wide range of features than is included in existing reporting schemes. Our scheme allows a richer characterization of calcifications, potentially improving the reporting and understanding of these abnormalities.

Image-guided core-needle breast biopsy is an accurate technique to evaluate patients with nonpalpable imaging abnormalities

OBJECTIVE

The goal was to evaluate one institution's experience with image-guided core-needle breast biopsy (IGCNBB) and compare the pathologic results with wire-localized excisional breast biopsy (WLEBB) for patients with positive cores and the mammographic surveillance results for patients with negative cores.

SUMMARY BACKGROUND DATA

IGCNBB is becoming a popular, minimally invasive alternative to WLEBB in the evaluation of patients with nonpalpable abnormalities.

METHODS

This study includes all patients with nonpalpable breast imaging abnormalities evaluated by IGCNBB from July 1993 to February 1997. Patients with positive cores (atypical hyperplasia, carcinoma in situ, or invasive carcinoma) were evaluated by WLEBB. Patients with negative cores (benign histology) were followed with a standard mammographic protocol. IGCNBB results were compared with WLEBB results to determine the sensitivity and specificity for each IGCNBB pathologic diagnosis.

RESULTS

Of 1440 IGCNBBs performed during the study period, 1106 were classified as benign, and during surveillance follow-up only a single patient was demonstrated to have a carcinoma in the index part of the breast evaluated by IGCNBB (97.3% sensitivity, 99.7% specificity). IGCNBB demonstrated atypical hyperplasia in 72 patients, 5 of whom refused WLEBB. The remaining 67 patients were evaluated by WLEBB: nonmalignant findings were found in 31, carcinoma in situ was found in 25, and invasive carcinoma was found in 11 (100% sensitivity, 88.8% specificity). IGCNBB demonstrated carcinoma in situ in 84 patients; WLEBB confirmed carcinoma in situ in 54 and invasive carcinoma in 30 (65.4% sensitivity, 97.7% specificity). IGCNBB demonstrated invasive carcinoma in 178 patients. Three were lost to follow-up. On WLEBB, 173 of the remaining 175 had invasive carcinoma; the other 2 patients had carcinoma in situ (80.8% sensitivity, 99.8% specificity).

CONCLUSIONS

An IGCNBB that demonstrates atypical hyperplasia or carcinoma in situ requires WLEBB to define the extent of breast pathology. Mammographic surveillance for a patient with a benign IGCNBB is supported by nearly 100% specificity. An IGCNBB diagnosis of invasive carcinoma is also associated with nearly 100% specificity; therefore, these patients can have definitive surgical therapy, including axillary dissection or mastectomy, without waiting for the pathologic results of a WLEBB. Based on the authors' findings, IGCNBB can safely replace WLEBB in evaluating patients with nonpalpable breast abnormalities.

Rate of insufficient samples for fine-needle aspiration for nonpalpable breast lesions in a multicenter clinical trial: The Radiologic Diagnostic Oncology Group 5 Study. The RDOG5 investigators

BACKGROUND

Radiologic Diagnostic Oncology Group 5 is a multicenter clinical trial designed to evaluate fine-needle aspiration (FNA) of nonpalpable breast lesions performed by multiple operators using the same protocol.

METHODS

Four hundred and nineteen women with mammographically detected nonpalpable breast lesions were enrolled on the trial at 18 institutions. Group A institutions randomized women to stereotactically guided FNA (SFNA) followed by stereotactically guided core needle biopsy (SCNB), or SCNB only. Group B institutions randomized women to SFNA and SCNB, SCNB, or ultrasonographically guided FNA followed by ultrasonographically guided core needle biopsy (USCNB), or USCNB only. A total of 377 women were eligible for analysis.

RESULTS

FNA yielded 128 insufficient samples for the 377 patients (33.95%; 95% confidence interval, 29.2-38.7%). The rate of insufficient samples varied by type of lesion with calcified lesions associated with a significantly higher rate of insufficient sampling than masses (P < 0.001). The radiologist's level of suspicion of the lesion was not a statistically significant predictor of insufficient samples for mass lesions, but was a predictor for calcified lesions. For the 336 lesions for which histologic information was available, insufficient samples occurred in significantly more benign than malignant lesions.

CONCLUSIONS

The high rate of insufficient samples for FNA of nonpalpable breast lesions in this multicenter trial makes its use impractical in this setting. Because of this factor, the study was terminated early.

Measures of acutance and shape for classification of breast tumors

Most benign breast tumors possess well-defined, sharp boundaries that delineate them from surrounding tissues, as opposed to malignant tumors. Computer techniques proposed to date for tumor analysis have concentrated on shape factors of tumor regions and texture measures. While shape measures based on contours of tumor regions can indicate differences in shape complexities between circumscribed and spiculated tumors, they are not designed to characterize the density variations across the boundary of a tumor. In this paper we propose a region-based measure of image edge profile acutance which characterizes the transition in density of a region of interest (ROI) along normals to the ROI at every boundary pixel. We investigate the potential of acutance in quantifying the sharpness of the boundaries of tumors, and propose its application to discriminate between benign and malignant mammographic tumors. In addition, we study the complementary use of various shape factors based upon the shape of the ROI, such as compactness, Fourier descriptors, moments, and chord-length statistics to distinguish between circumscribed and spiculated tumors. Thirty-nine images from the Mammographic Image Analysis Society (MIAS) database and an additional set of 15 local cases were selected for this study. The cases included 16 circumscribed benign, seven circumscribed malignant, 12 spiculated benign, and 19 spiculated malignant lesions. All diagnoses were proven by pathologic examinations of resected tissue. The contours of the lesions were first marked by an expert radiologist using X-Paint and X-Windows on a SUN-SPARCstation 2 Workstation. For computation of acutance, the ROI boundaries were iteratively approximated using a split/merge and end-point adjustment technique to obtain the best-fitting polygonal approximation. The jackknife method using the Mahalanobis distance measure in the BMDP (Biomedical Programs) package was used for classification of the lesions using acutance and the shape factors as features in various combinations. Acutance alone resulted in a benign/malignant classification accuracy of 95% the MIAS cases. Compactness alone gave a circumscribed/spiculated classification rate of 92.3% with the MIAS cases. Acutance in combination with a moment-based shape measure and a Fourier descriptor-based measure gave four-group classification rate of 95% with the MIAS cases. The results indicate the importance of including lesion edge definition with shape information for classification of tumors, and that the proposed measure of acutance fills this need.

A new human breast cancer cell line, KPL-3C, secretes parathyroid hormone-related protein and produces tumours associated with microcalcifications in nude mice

Parathyroid hormone-related protein (PTHrP) is the main cause of humoral hypercalcaemia of malignancy (HHM). We recently established a new human breast cancer cell line, designated KPL-3C, from the malignant effusion of a breast cancer patient with HHM. Morphological, cytogenetic and immunohistochemical analyses indicated that the cell line is derived from human breast cancer. The KPL-3C cells stably secrete immunoreactive PTHrP measured by a two-site immunoradiometric assay, possess both oestrogen and progesterone receptors and are tumorigenic in female nude mice. The addition of phorbol-12-myristate-13-acetate to the medium significantly increased PTHrP secretion from the cells. In contrast, hydrocortisone, medroxyprogesterone acetate and 22-oxacalcitriol decreased PTHrP secretion in a dose-dependent manner. Unexpectedly, a number of microcalcifications were observed in the transplanted tumours. Radiographical examination indicated that the microcalcifications in the tumours are very similar to those commonly observed in human breast cancer. These findings suggest that this KPL-3C cell line may be useful for studying the regulatory mechanisms of PTHrP secretion and the mechanisms that lead to the deposition of microcalcifications in breast cancer.

Microcalcification clustering parameters in breast disease: a morphometric analysis of radiographs of excision specimens

X-ray microradiography of surgically excised breast specimens offers the possibility of morphological characterization of calcifications. When combined with digital imaging techniques there exists added potential for obtaining valuable basic quantitative morphometric information regarding differences between microcalcifications in tissues exhibiting evidence of fibrocystic change, benign and malignant tumours. A total of 157 excised breast specimens from 84 patients were microradiographed using a Softex Super Soft X-ray unit and Kodak AA high resolution industrial film. A Quantimet 570C image analysis system was used to digitize and analyse the microradiographs. Of the 157 microradiographs, 51 (from 30 patients) revealed microcalcification clusters. The existence of significant differences between the three identified categories of tissue were indicated by clustering parameters. These included the number of particles per cluster, area of clusters, maximum distance to nearest neighbour, and geometric mean distance to nearest neighbour. The distribution pattern index (DPI), another of the clustering parameters used in this study, has been observed to be a particularly powerful discriminator. The value for fibrocystic change was found to be significantly smaller (0.514) than that for benign tumour (0.796) whilst that for benign tumour was observed to be significantly larger than that for malignant tumour (0.604) at a p-value of less than 0.05 (Kruskal-Wallis one-way analysis of variance).

Results of needle localized breast biopsy in women under age 50

BACKGROUND

The use of screening mammography in women aged 40 to 50 years is controversial because of a relative lack of data demonstrating survival benefit for this segment of the population.

PATIENTS AND METHODS

The charts of 809 consecutive women who underwent needle localized breast biopsy over a 6 1/2-year period were reviewed to determine the effect of age on the biopsy results. Patient ages ranged from 27 to 91 years (mean 56).

RESULTS

Two hundred nineteen (27%) of the 809 needle localized breast biopsies were malignant, with a mean tumor diameter of 1.46 cm. This procedure identified malignancy in 3 (5%) of 60 patients age 40, and in 32 (15%) of 207 patients aged 40 to 49 years. Malignancy was significantly more likely in patients 50 years of age or older and was found in 184 (34%) of the 542 (P<0.001). Overall, 33% of all patients undergoing the procedure were under age 50.

CONCLUSIONS

Without screening mammography, the diagnosis of breast cancer would have been delayed in 32 women aged 40 to 50, 15% of the total diagnosed with nonpalpable breast cancer in this study. We recommend the use of screening mammography in this age group.

Breast disease

Breast diseases are a common aspect of primary care practice. Common benign and malignant breast diseases are reviewed. The evaluation of common breast problems is presented and current recommendations for diagnostic and screening mammography are discussed.

Management of ductal carcinoma in situ

Ductal carcinoma in situ (DCIS) is an early, localized stage of breast carcinoma that has an excellent prognosis when it is properly treated. The significant increase in the frequency of diagnosis of DCIS in recent years is the result of both better recognition of DCIS among pathologists and widespread use of screening mammography. Multicentricity, bilaterality and histologic subtype are important considerations in the management of this disease. The clinical presentation of DCIS is the presence of either a palpable mass or a mammographic abnormality, most frequently in the form of an area of microcalcifications. For several decades, total mastectomy was considered the appropriate treatment for DCIS, and it should still be considered the standard to which more conservative forms of treatment must be compared. Breast conservation surgery has been used with increasing frequency in the treatment of DCIS but the adequacy of this approach remains subject to controversy. Segmental mastectomy alone may be applied with caution in carefully selected patients, while the rest of the patients undergoing breast conservation surgery should be treated with breast irradiation. Axillary node dissection is generally considered unnecessary in the treatment of DCIS. There is no role for adjuvant chemotherapy in the management of this disease. The role of tamoxifen in the treatment of DCIS is not clearly defined and it should be given only to patients enrolled in clinical trials. Ongoing research should clarify the controversies surrounding DCIS and enable us to define the optimal management for this disease.

Breast biopsy rate and positivity in Rhode Island

Breast biopsy is a common procedure for which few age-specific, population-based data are available. We identified all women who underwent breast biopsy in Rhode Island in 1989 by reviewing the specimen logs at each of 13 pathology laboratories. Among 425,000 women aged 15-97 years, 2685 underwent breast biopsy, for an overall rate of 6/1000. The rate increased with age, peaking among 45- to 54-year-olds and then declining in women over 75. Among those biopsied, 726 were diagnosed with breast cancer, for an overall biopsy positivity of 27%. In contrast to rate, positivity increased steadily with age. These results are within the range of estimates produced by smaller group studies.

Management of in situ and minimally invasive breast carcinoma

In situ breast carcinoma represents an early localized stage in the transition to invasive breast carcinoma and has an especially favorable prognosis with appropriate management. The widespread use of mammography has contributed to its increased rate of diagnosis. The two histologic forms of this entity have distinct pathologic and biologic characteristics, with different therapeutic implications. Lobular carcinoma in situ is considered a marker of increased risk for subsequent invasive carcinoma and is most commonly managed by nonoperative surveillance. Ductal carcinoma in situ behaves more as a true anatomic precursor of invasive disease and has the same therapeutic options as invasive breast carcinoma. Minimally invasive breast carcinoma should be considered a fundamentally different entity, primarily because of its potential for systemic metastasis that in situ lesions do not theoretically have. There are still many outstanding issues and dilemmas to be resolved by scientific investigation before the intriguing potential of these early forms of breast malignancy are fully understood.

Selective digital enhancement of conventional film mammography

Screening mammography continues to play a key role in the early diagnosis of non-palpable breast cancer. Approximately 5% of patients will have lesions on their mammograms that appear neither clearly benign nor malignant. The proper management of these patients is not well defined. In this study, the mammograms of 64 women who underwent breast biopsy were reviewed. After the initial review, the mammograms were reevaluated using a personal computer driven digital conversion and enhancement system. The majority of indeterminate lesions were assigned a determinate diagnosis by enhancing the areas of abnormality through enlargement, contrast adjustment, and brightness adjustment. The radiologists were able to maintain baseline sensitivity and specificity throughout this process. In contrast, enhancement of lesions initially assigned a diagnosis of characteristically benign or malignant demonstrated no advantage over plain film mammography. These findings suggest a role for the selective use of digital mammography and enhancement techniques.

Breast disease: the radiologist's expanding role

The role of the diagnostic radiologist in breast cancer has expanded during the eight-decade history of breast imaging. The radiologist's role now encompasses both breast cancer diagnosis and treatment. This article traces the expansion of the radiologist's role through the history of mammography. The current roles of the radiologist in breast cancer diagnosis are discussed, including screening mammography in the asymptomatic patient, problem-solving breast imaging, breast ultrasound, and galactography. The radiologist's roles in breast cancer treatment that are discussed include preoperative needle localization, percutaneous breast biopsy, and evaluation of the postoperative breast.

Pathology and treatment of impalpable breast lesions

With the increasing use of mammography, more needle-localized breast biopsies (NLBB) are being done. The purpose of this study was to analyze the pathology of impalpable breast lesions and the impact of NLBB on treatment strategies. From 1985 to 1990, 1,605 NLBB were performed, of which 321 (20%) were malignant. Twenty-five percent of malignant biopsies demonstrated in situ disease only. The average size of all lesions detected was 16 mm, and, for invasive cancer, 12 mm. Eighteen percent of invasive cancers had metastasized to the axillary lymph nodes. Surgical management consisted of mastectomy in 74% of patients and breast conservation treatment (BCT) in 26%. No significant difference in surgical management for women 50 years of age or younger compared with those older than 50 years of age was noted. Although the use of BCT for eligible women is recommended by the National Institutes of Health, it is not widely practiced, possibly reflecting less physician acceptance of BCT. These observations suggest that the detection of smaller, impalpable breast cancers has had no impact on treatment strategies.

Mammogram-directed fine-needle aspiration of nonpalpable breast lesions

A prospective study was undertaken to evaluate the effectiveness of mammogram directed fine-needle aspiration cytology in women with nonpalpable abnormalities detected on mammogram. Seventy patients were entered into the research protocol, with 61 patients undergoing mammogram directed fine-needle aspiration. Forty-three of the aspirates were adequate for diagnosis. Fine-needle aspiration yielded an accurate diagnosis in 12 of the 14 carcinomas in which the sample was considered adequate, for a sensitivity of 87%. No patients were falsely diagnosed with malignant disease, a specificity of 100%. The predictive value of a positive test was 100%, and that of a negative test was 93%. We conclude that fine-needle aspiration cytology can aid in making a diagnosis when nonpalpable breast abnormalities are detected on mammogram.

Surgical considerations in needle localization procedures

There is an increasing need for needle localization biopsies. Cancers so detected are usually at an earlier stage and should result in an increased cure rate. The surgeon involved in these procedures should, of necessity, be proficient in evaluating mammographic abnormalities, since there is considerable variation in the way they are reported by various radiologists. Localization can be accomplished with various hooked wires or dye, but accuracy of placement is more important than the method used and this point is well understood by cooperative radiologists. Since 70-80% of these lesions will be benign, cosmesis should be kept in mind. Incisions should be placed centrally, if possible, and the volume excised should be minimal and not lead to deformity. When poorly localized, excision of these lesions can be a trying experience for the experienced surgeon.