Magnetic resonance imaging-guided biopsy of mammographically and clinically occult breast lesions

MRI vacuum-assisted breast biopsies

The indications, technique, results and limitations of MRI vacuum-assisted breast biopsies are discussed from a review of the literature. This was initially a home-grown technique and its development was slowed down by several factors. As a result of major technical advances, it has become a reliable and very consistent procedure with a low rate of underestimation. It is now an undisputed technique when suspicious MRI enhancement is seen with no corresponding mammography or ultrasound features.

Impact of clinical and lesion characteristics on the results of MR-guided wire localizations of the breast using an open 1.0-T MRI system

PURPOSE

Preoperative magnetic resonance (MR)-guided wire localizations are warranted in patients with suspicious focal breast lesions on MR mammographic findings without equivalent in x-ray mammography and ultrasonography. The study was performed to assess the impact of clinical parameters, tumor size, and target localization on the procedural characteristics in magnetic resonance imaging (MRI)-guided wire localizations of breast lesions using an open 1.0-T open MR system.

MATERIAL AND METHODS

The clinical, radiological, and histological characteristics of all 347 patients and all 394 interventional procedures performed in a 6-year interval were extracted from the clinical files. Two board-certified senior radiologists evaluated the impact of target localization and the size on the interventional results in the available 302 image data sets. Patient characteristics, lesion characteristics, and interventional results were statistically correlated in subgroup analyses.

RESULTS

A total of 387 of the 394 MR-guided wire localizations (98.2%) were technically successful. In 7 cases (2.3%), the intervention was aborted because the suspicious finding of the diagnostic MR mammography could not be visualized during the intervention. Minor complications occurred in 13 interventions (3.3%). The histological workup of the operative specimen showed benign results in 226 of the 394 interventions (57.4%) and malignant findings in 154 wire localizations (39.1%). The mean (SD) length of the interventional procedure time defined as the time interval between the start of the first and of the last MRI sequence as documented in the electronic MRI data sets was 24.6 (8.4) minutes. Patient age, medical history, and the anticipated risk for developing breast cancer and a simultaneous known carcinoma did not affect the technical success and complication rates and the interventional procedure time. A total of 60 targets (19.5%) were located in the retromamillary zone, 89 targets (28.9%) in the peripheral zone, and 1 target (0.3%) near the chest wall. The maximum diameter was 1 to 5 mm in 64 lesions (21.2%), 6 to 10 mm in 136 lesions (45.0%), 11 to 15 mm in 56 lesions (18.6%), and 16 mm or greater in 46 lesions (15.2%). A total of 23 of the 100 histologically proven invasive carcinomas had a maximum MRI diameter of 1 to 5 mm (23.0%) and 38 (38.0%) of 6 to 10 mm.

CONCLUSIONS

Magnetic resonance-guided wire localizations of suspicious breast lesions using an open high-field MR system are a clinically safe and feasible method even in small target lesions and anatomical regions that are usually considered difficult to access.

Magnetic resonance imaging-radioguided occult lesion localization (ROLL) in breast cancer using Tc-99m macro-aggregated albumin and distilled water control

Background

Magnetic resonance imaging (MRI) guided wire localization presents several challenges apart from the technical difficulties. An alternative to this conventional localization method using a wire is the radio-guided occult lesion localization (ROLL), more related to safe surgical margins and reductions in excision volume. The purpose of this study was to establish a safe and reliable magnetic resonance imaging-radioguided occult lesion localization (MRI-ROLL) technique and to report our initial experience with the localization of nonpalpable breast lesions only observed on MRI.

Methods

Sixteen women (mean age 53.2 years) with 17 occult breast lesions underwent radio-guided localization in a 1.5-T MR system using a grid-localizing system. All patients had a diagnostic MRI performed prior to the procedure. An intralesional injection of Technetium-99m macro-aggregated albumin followed by distilled water was performed. After the procedure, scintigraphy was obtained. Surgical resection was performed with the help of a gamma detector probe. The lesion histopathology and imaging concordance; the procedure’s positive predictive value (PPV), duration time, complications, and accuracy; and the rate of exactly excised lesions evaluated with MRI six months after the surgery were assessed.

Results

One lesion in one patient had to be excluded because the radioactive substance came back after the injection, requiring a wire placement. Of the remaining cases, there were four malignant lesions, nine benign lesions, and three high-risk lesions. Surgical histopathology and imaging findings were considered concordant in all benign and high-risk cases. The PPV of MRI-ROLL was greater if the indication for the initial MR examination was active breast cancer. The median procedure duration time was 26 minutes, and all included procedures were defined as accurate. The exact and complete lesion removal was confirmed in all (100%) patients who underwent six-month postoperative MRI (50%).

Conclusions

MRI-ROLL offers a precise, technically feasible, safe, and rapid means for performing preoperative MRI localizations in the breast.

3.0 Tesla vs 1.5 Tesla breast magnetic resonance imaging in newly diagnosed breast cancer patients

AIM: To compare 3.0 Tesla (T) vs 1.5T magnetic resonance (MR) imaging systems in newly diagnosed breast cancer patients.

METHODS: Upon Institutional Review Board approval, a Health Insurance Portability and Accountability Act-compliant retrospective review of 147 consecutive 3.0T MR examinations and 98 consecutive 1.5T MR examinations in patients with newly diagnosed breast cancer between 7/2009 and 5/2010 was performed. Eleven patients who underwent neoadjuvant chemotherapy in the 3.0T group were excluded. Mammographically occult suspicious lesions (BIRADS Code 4 and 5) additional to the index cancer in the ipsilateral and contralateral breast were identified. Lesion characteristics and pathologic diagnoses were recorded, and results achieved with both systems compared. Statistical significance was analyzed using Fisher’s exact test.

RESULTS: In the 3.0T group, 206 suspicious lesions were identified in 55% (75/136) of patients and 96% (198/206) of these lesions were biopsied. In the 1.5T group, 98 suspicious lesions were identified in 53% (52/98) of patients and 90% (88/98) of these lesions were biopsied. Biopsy results yielded additional malignancies in 24% of patients in the 3.0T group vs 14% of patients in the 1.5T group (33/136 vs 14/98, P = 0.07). Average size and histology of the additional cancers was comparable. Of patients who had a suspicious MR imaging study, additional cancers were found in 44% of patients in the 3.0T group vs 27% in the 1.5T group (33/75 vs 14/52, P = 0.06), yielding a higher positive predictive value (PPV) for biopsies performed with the 3.0T system.

CONCLUSION: 3.0T MR imaging detected more additional malignancies in patients with newly diagnosed breast cancer and yielded a higher PPV for biopsies performed with the 3.0T system.

Preliminary Results: Double Lumpectomies for Multicentric Breast Carcinoma

The standard operation for patients with multicentric breast cancer is total mastectomy. The safety of breast-conserving surgery (BCS) for these patients is unknown but interest in BCS has recently resurfaced as a result of the detection of occult second malignancies by breast magnetic resonance imaging (MRI). We report a small number of patients who chose to undergo “double lumpectomies,” defined as two separate segmental mastectomies for primary cancers in different quadrants of the same breast. Patients with multicentric breast cancer surgically managed with double lumpectomies at our institute were identified retrospectively. Clinicopathologic features are described and outcomes reported. Seven patients underwent double lumpectomies for multicentric carcinoma. Median age was 69 years (range, 61 to 80 years). In five patients, MRI identified ipsilateral second malignancies. All patients had two foci of invasive carcinoma, all tumors expressed estrogen receptor, and none showed HER-2 overexpression. Tumor sizes ranged from 0.7 to 2.9 cm. Six patients had histologically distinct tumors in the same breast: five had one invasive lobular carcinoma (ILC) and one invasive ductal carcinoma (IDC), and one had classic ILC in one quadrant and pleomorphic ILC in another. One patient had two foci of IDC in separate quadrants. All patients had sentinel lymph node biopsies and none had nodal metastasis. Median follow-up was 26 months (range, 18 to 85 months). No patient developed locoregional recurrence. This small series suggests that “double lumpectomy” may be considered for multicentric invasive breast carcinoma in carefully selected patients with favorable tumors who desire breast conservation.

Comparison of outcomes of breast conserving therapy in multifocal and unifocal invasive breast cancer

BACKGROUND

There is controversy about whether breast conserving therapy (BCT) should be contraindicated in multifocal (MF) breast cancer. Few studies have reported on the oncologic safety of BCT in MF breast cancer.

STUDY DESIGN

We reviewed a prospective database of 1,169 women with invasive breast cancer who were treated with segmentectomy and whole breast irradiation from 1991 through 2009 and followed at our institution. Multifocal breast cancer was defined as 2 or more distinct tumors excised with a single incision or segmentectomy. We compared 2 groups, MF and unifocal breast cancer patients, with respect to demographics, tumor characteristics, adjuvant systemic therapy, local recurrence (LR), disease-free survival (DFS), and overall survival (OS).

RESULTS

One hundred sixty-four patients with MF and 999 with unifocal invasive breast cancer were treated with BCT. Median follow-up was 112 months. Compared with the unifocal group, patients in the MF group had higher 10-year LR (0.6% vs 6.1%, p < 0.001) and lower 10-year DFS (97.7% vs 89.3%, p < 0.001) and OS (98.4% vs 85.8%, p < 0.001). On multivariable analysis, multifocality was independently significantly associated with local recurrence-free survival (LRFS), DFS, and OS.

CONCLUSIONS

Our data suggest that BCT in MF breast cancer is oncologically safe but may result in a slightly inferior outcome compared with BCT in unifocal breast cancer.

Real-time virtual sonography, a coordinated sonography and MRI system that uses magnetic navigation, improves the sonographic identification of enhancing lesions on breast MRI

This study verified that recently developed real-time virtual sonography (RVS) to coordinate a sonography image and the magnetic resonance imaging (MRI) multiplanar reconstruction (MPR) with magnetic navigation was useful. The purpose of this study was to evaluate the accuracy of RVS to sonographically identify enhancing lesions by breast MRI. Between December 2008 and May 2009, RVS was performed in 51 consecutive patients with 63 enhancing lesions. MRI was performed with the patients in the supine position using a 1.5-T imager with a body surface coil to achieve the same position as with sonography. To assess the accuracy of the RVS, the following three issues were analyzed: (i) The sonographic detection rate of enhancing lesions, (ii) the comparison of the tumor size measured by sonography and the MRI-MPR and (iii) the positioning errors as the distance from the actual sonographic position to the expected MRI position in 3-D. Among the 63 enhancing lesions, 42 (67%) lesions were identified by conventional B-mode, whereas the remaining 21 (33%) initial conventional B-mode occult lesions were identified by RVS alone. The sonographic size of the lesions detected by RVS alone was significantly smaller than that of lesions detected by conventional B-mode (p < 0.001). The mean tumor size provided by RVS was 12.3 mm for real-time sonography and 14.1 mm for MRI-MPR (r = 0.848, p < 0.001). The mean positioning errors for the transverse and sagittal planes and the depth from the skin were 7.7, 6.9 and 2.8 mm, respectively. The overall mean 3D positioning error was 12.0 mm. Our results suggest that RVS has good targeting accuracy to directly compare a sonographic image with MRI results without operator dependence.

Magnetic resonance imaging of the breast for cancer diagnosis and staging

Gadolinium-enhanced breast magnetic resonance imaging (MRI) is optimally suited for the diagnosis and assessment of breast cancer. The complete breast MRI examination, which includes select nonenhanced sequences, yields abundant information about the nature and stage of disease. In this article, we will explore cancer diagnosis by examining the main imaging features of breast malignancy as well as the assessment of surrounding structures. We will then discuss current ideas in the use of breast MRI in breast cancer, including high-risk screening, evaluation of extent of disease, role in surgical planning, and the use of MRI in the patient receiving neoadjuvant chemotherapy. Breast MRI plays an important role in the assessment of patients with breast malignancy-a role that is yet to be fully defined and used. By understanding the strengths and weakness of this imaging method in cancer evaluation, we hope to highlight the appropriate uses of the technique.

Role of magnetic resonance imaging in evaluating the extent of disease

Preoperative breast imaging evaluation can contribute useful clinical information to the management of the patient with known breast cancer. Breast magnetic resonance imaging (MRI) has been used as part of this imaging evaluation, and the ability of breast MRI to detect otherwise occult multifocal and multicentric disease has been demonstrated in multiple studies. The use of MRI for breast cancer staging remains under debate, however. This article reviews some of the current discussion regarding the use of breast MRI in this patient population. It is important to note that this discussion occurs in an evolving context of surgical and breast conservation therapies.

Magnetic resonance imaging--guided breast interventions

The use of breast magnetic resonance imaging (MRI) for screening, diagnosis, staging, and management of breast cancer is rapidly increasing. MRI is highly sensitive for the detection of benign and malignant abnormalities that are occult to physical examination, ultrasound, and mammography. However, the specificity of MRI is moderate. These attributes necessitate methods for MR-guided tissue sampling to determine the histology of MRI detected lesions. This article will review appropriate peer-reviewed data and currently accepted methods for MR-guided tissue sampling. A detailed step-by-step technique for vacuum-assisted MR-guided breast biopsy is included. We also review emerging data for percutaneous and transcutaneous MR-guided breast interventions such as tissue ablation for benign and malignant disease.

MRI-directed, wire-localized breast excisions: incidence of malignancy and recommendations for pathologic evaluation

Magnetic resonance imaging (MRI) has an evolving role in the evaluation of breast lesions and is currently being used for the screening of high-risk patients (eg, women with a personal or family history of breast cancer), for the evaluation of extent of disease in patients with a current diagnosis of cancer, and for patients with suspicious, but indeterminate, findings by other imaging modalities. If a suspicious lesion detected by MRI is not well visualized by another method, an MRI-directed core biopsy or breast excision may be performed. MRI cannot be used to verify the lesion in the specimen because MRI lesion detection is dependent on uptake of gadolinium after intravenous injection. Accordingly, these breast excisions present unique challenges to pathologists. The purpose of this report is to define the surgical pathology issues involved in processing MRI-localized excisions. Retrospective review of 85 consecutive MRI-directed breast excisions from 77 patients was performed. Malignant lesions were present in 20 (24%) of 85 excisions, including 10 cases of invasive carcinoma (median size, 0.4 cm), 9 cases of ductal carcinoma in situ, and 1 case of lymphoma. Most of the malignancies (85% or 17/20) had no associated gross finding and only 5 (25%) of 20 of these malignancies were associated with a definite finding on the specimen radiograph. This study demonstrates that gross examination and specimen radiography do not identify most of the malignancies in MRI-localized biopsies and, therefore, optimal processing requires complete microscopic examination of these specimens.

A multidisciplinary approach to the management of breast cancer, part 1: prevention and diagnosis

Breast cancer is the most common cancer among women in the United States, with an estimated 200,000 new cases diagnosed annually. A multidisciplinary focus that entails prevention, diagnosis, and treatment has led to significant strides in the reduction of breast cancer incidence and mortality. Additionally, breast cancer management has become increasingly complex, requiring comprehensive assessment and review of multiple issues that include the role of genetic testing, imaging and breast magnetic resonance imaging, surgical and reconstructive options, and a variety of new adjuvant therapies. It has become more evident that a multidisciplinary team approach that involves a spectrum of breast experts is necessary to provide optimal care to patients. This team includes medical oncologists, breast radiologists, breast pathologists, surgical breast specialists, radiation oncologists, geneticists, and primary care physicians. Furthermore, patient knowledge has increased use of the Internet, and more patients are seeking a multidisciplinary approach to treatment. This review considers information for health care professionals who will facilitate optimal patient care for women at increased risk for or presenting with a new diagnosis of breast cancer. The multidisciplinary team of authors, representing the different disciplines, has selected important state-of-the-art issues that arise in their daily practices for consideration, rather than summarizing what is already available in textbooks.

Detecting Occult Malignancy in Prophylactic Mastectomy: Preoperative MRI Versus Sentinel Lymph Node Biopsy

BACKGROUND

High-risk patients undergoing prophylactic mastectomy (PM) may have unsuspected cancers identified on pathology. The optimum way to identify and manage them is controversial. Magnetic resonance imaging (MRI) may identify occult cancer preoperatively. Sentinel lymph node biopsy (SLNB) allows intraoperative staging and axillary dissection during the same operation. We determined the efficacy and cost of MRI and/or SLNB in managing high-risk PM patients.

METHODS

We reviewed 192 PMs in 173 patients from 1999 to 2005. Costs were estimated for MRI and SLNB during PM by the 2005 Medicare Resource-Based Relative Value Scale. We also estimated costs and procedures for the four strategies in a larger hypothetical cohort.

RESULTS

A total of 19 (10%) of 192 PMs contained occult cancers, 14 ductal carcinoma-in-situ (DCIS) and 5 invasive ductal carcinoma (IDC). In 59 patients, MRI detected an IDC but missed two DCIS and an IDC. Positive MRIs generated an additional average cost of $1,207 per patient. In 56 PMs with SLNB, 6 occult cancers were found, 5 DCIS and 1 IDC, all with negative SLNBs. Adding a SLNB costs an additional average of $644. A theoretical analysis demonstrated that PM alone costs $808 per patient, PM with SLNB costs $1,420, PM with MRI and selective SLNB costs $1,774, and PM with routine MRI and SLNB costs $2,379.

CONCLUSIONS

MRI adds great cost and misses most occult cancers in PMs. SLNB allows the rare patient with occult IDC to avoid axillary dissection but adds cost. Given the low rate of unsuspected invasive cancers and the costs of MRI and SLNB, neither is recommended as standard practice for PM patients.

Breast MR imaging in assessing extent of disease

Breast MR imaging is valuable in assessment of extent of disease in the ipsilateral and contralateral breast in women who have breast cancer. In the ipsilateral breast, MR imaging depicts otherwise unsuspected sites of cancer in 16% (range, 6%-34%). In the contralateral breast, MR imaging depicts otherwise unsuspected sites of cancer in 6% (range, 3%-24%). MR imaging is most likely to depict additional sites of cancer in women with invasive lobular cancer and a family history of breast cancer. MR imaging can also assist in evaluating involvement of skin, pectoral muscle, and chest wall. Disadvantages of breast MR imaging include cost and additional procedures (follow-up and biopsy); furthermore, no data as yet show that breast MR imaging in the extend of disease evaluation improves disease-free or overall survival. If breast MR imaging is used in evaluating extent of disease, it is necessary to have the capability to perform biopsy of lesions detected by MR imaging only.

MRI-Guided Breast Interventions

The use of breast magnetic resonance imaging (MRI) in the diagnosis, staging, and management of breast cancer is rapidly increasing. MRI has the ability to detect malignancy that is occult to physical exam, ultrasound, and mammography. These qualities necessitate methods for MRI-guided tissue sampling. This article reviews all previously published and currently accepted methods for MRI-guided tissue sampling. The data to support these techniques are provided where appropriate. A detailed technique for vacuum-assisted breast biopsy is included. We will also review the data on other MRI-guided breast interventions such as transcutaneous tissue ablation.

MRI-guided preoperative wire localization of nonpalpable breast lesions

With the increasing use of magnetic resonance imaging (MRI), the physician is more frequently confronted with nonpalpable breast lesions that are only visible on MRI. In these cases, it is often difficult to obtain adequate material for pathological examination. One of the methods that may be performed is excisional biopsy after MRI-guided wire localization. This study intends to examine the feasibility and added benefit of this method. It appears to be a reliable and useful tool that is, therefore, of additional benefit to surgical practice.

MRI-guided needle localization of suspicious breast lesions: results of a freehand technique

Magnetic resonance imaging (MRI) can detect clinically and mammographically occult breast lesions. In this study we report the results of MRI-guided needle localization of suspicious breast lesions by using a freehand technique. Preoperative MRI-guided single-needle localization was performed in 220 patients with 304 MRI-only breast lesions at our hospital between January 1997 and July 2004. Procedures were performed in an open 0.5-T Signa-SP imager allowing real-time monitoring, with patient in prone position, by using a dedicated breast coil. MRI-compatible hookwires were placed in a noncompressed breast by using a freehand technique. MRI findings were correlated with pathology and follow-up. MRI-guided needle localization was performed for a single lesion in 150 patients, for two lesions in 56 patients, and for three lesions in 14 patients. Histopathologic analysis of these 304 lesions showed 104 (34%) malignant lesions, 51 (17%) high-risk lesions, and 149 (49%) benign lesions. The overall lesion size ranged from 2.0-65.0 mm (mean 11.2 mm). No direct complications occurred. Follow-up MRI in 54 patients showed that two (3.7%) lesions were missed by surgical biopsy. MRI-guided freehand needle localization is accurate and allows localization of lesions anterior in the breast, the axillary region, and near the chest wall.

A case of occult contralateral breast cancer incidentally detected by contrast-enhanced MRI; report of a case with review of literature

We encountered a case of occult contralateral breast cancer, previously undetected by conventional imaging such as mammography (MMG) and ultrasonography (US), but incidentally detected by contrast-enhanced magnetic resonance imaging (CE-MRI). We present it here with a review of the literature. A 67-year-old Japanese woman was referred to our hospital in October 2000 because of a 1.5 cm right breast lump detected in a medical checkup. MMG, US and fine needle aspiration cytology revealed a cancerous lesion during the right breast. No mass lesion was palpable nor was any detected by MMG or US in the left breast. Bilateral breast CE-MRI was performed for more detailed evaluation. Consequently, an occult contralateral breast cancerous lesion was detected incidentally by CE-MRI, with the images showing rapid initial enhancement of time to signal intensity curves. Before surgery, bilateral breast lesions were diagnosed as invasive ductal carcinoma by open biopsy. She underwent bilateral breast conserving surgery with bilateral axillary lymph node dissection. The postoperative course was uneventful and no recurrence has been noted as of January 18th, 2004. CE-MRI of the contralateral breast should be of value as a routine screen in those patients with a known or suspected malignancy in one breast considering the limits of breast cancer detection by such conventional modalities as MMG and US.

MRI in the detection and management of breast cancer

Breast magnetic resonance imaging (MRI) is now at a stage where the evidence is suggesting widespread potential in the management of patients with known or suspected breast cancers. MRI is used as a supplementary tool to complement conventional methods of breast evaluation because it has excellent problem-solving capabilities. Many indications for clinical breast MRI are recognized, including resolving findings on mammography, staging of breast cancer when multiple or bilateral disease is suspected, and detecting the occult primary breast cancer presenting with malignant axillary lymphadenopathy but no detectable lesion on conventional breast examination. There is also encouraging ongoing research evaluating its role for the assessment of patients at high risk of breast cancer, for primary staging of cancers in radiographically dense breasts and for the assessment of response to chemotherapy. This article will review both the technical aspects of performing and interpreting breast MRI, as well as the current and possible future roles of breast MRI, comparing its strengths and weaknesses with conventional imaging.

An MRI/US/x-ray compatible breast localization marker: in vivo evaluation

RATIONALE AND OBJECTIVES

An in vivo evaluation of a new trimodality breast localization marker was performed with magnetic resonance imaging (MRI), ultrasound (US), x-ray, and histopathology. The evaluation of the marker in animal tests should help define its utility for surgical biopsy localization in humans.

MATERIALS AND METHODS

Five rabbits were used and sacrificed at 2 days, 1 week, 2 weeks, 4 weeks, and 7 weeks after marker implantation. The marker placement and tissue biopsies were performed under US guidance. MRI, US, and x-ray imaging were performed to monitor the contrast of the marker, track marker migration. The biologic compatibility of the marker was demonstrated by histopathologic analysis.

RESULTS

The contrast of the marker was clear and stable on each imaging modality over the 7-week study period. Acute inflammation was visible by 2 days after marker injection, with evidence of granulation tissue and angiogenesis at 2 weeks after implantation. A modest degree of chronic inflammation and angiogenesis remained evident at 4 weeks after procedure, and fibrosis persisted 7 weeks after procedure with no further tissue changes. These results suggest that the new marker is biocompatible and can remain interstitial for up to 7 weeks. Furthermore, very little marker migration was observed. On removal, the marker was found to be mechanically stable.

CONCLUSION

This in vivo animal study demonstrates that the new marker may be appropriate for in vivo human testing and as an alternative to traditional wire localization currently used for breast surgery.

Screening women at increased risk with MRI

Breast cancer is the most common cancer affecting women. In the screening of women for breast cancer, mammography is the most used imaging modality. Women with an increased risk for getting breast cancer can develop a malignancy at a relatively young age compared to other women. The increased risk for developing breast cancer can usually be found in a positive familial history. This positive familial history is based on a gene mutation in 5-10% of cases. The most common gene mutations are BRCA1 and BRCA2. This risk makes it necessary to start screening these women at a young age. Mammography, however, has proven to be less reliable in younger women because its sensitivity is lowered due to the dense breast tissue often present in this group. MRI has a higher sensitivity for detecting breast cancer compared to mammography. MRI is not influenced by the density of the breast tissue. This makes breast MRI the best modality available for the screening of women with an increased risk for developing breast cancer.

Contrast-enhanced MRI in breast cancer patients eligible for breast-conserving therapy: complementary value for subgroups of patients

The aim of this study was to identify patients prior to breast-conserving therapy (BCT) who have complementary value of contrast-enhanced magnetic resonance imaging (MRI) over conventional imaging in the assessment of tumor extent. All patients were eligible for BCT according to conventional imaging, and underwent preoperative MRI as part of this study. One hundred and sixty-five patients (166 tumors) were included. MRI was defined to have complementary value if conventional imaging underestimated or overestimated tumor extent (by more than 10 mm compared to histology) and MRI assessed the extent accurately. Logistic regression was employed to identify characteristics that are predictive of the complementary value of preoperative MRI. MRI had complementary value in 39 cases (23%). Patients <58 years old with irregular lesion margins at mammography and discrepancy in tumor extent by more than 10 mm between mammography and ultrasonography had a 3.2x higher chance of accurate assessment at MRI (positive predictive value 50%, negative predictive value 84%, p=0.0002). Preoperative MRI in patients eligible for BCT is more accurate than conventional imaging in the assessment of tumor extent in approximately one out of four patients. Subgroups of patients in whom MRI has complementary value may be defined by the differences in clinical and imaging features.

[Breast MRI in invasive lobular carcinoma: diagnosis and staging]

PURPOSE

To assess the use of breast MRI for the diagnosis and staging of invasive lobular carcinoma and its impact on surgical management.

MATERIALS AND METHODS

Retrospective study of 35 invasive lobular carcinoma, histologically diagnosed in 34 patients who underwent clinical exam, mammography, ultrasonography and magnetic resonance imaging.

RESULTS

Enhancement at MRI was seen for all 35 cancers. It was focal for 24 patients, regional for 10 and diffuse for 1. The kinetic of the enhancement was characteristic of malignancy for 33 patients. For 11 patients the MRI staging was positive, finding 8 news cancers. For 3 patients MRI lead to biopsy of benign lesions but improved the surgical management in the 8 cases of new cancers: wider excision for 3 cases, planned breast conservation converted to mastectomy in 3 cases and excision of contralateral lesion in 2 cases.

CONCLUSION

Breast MRI is useful in diagnosis, staging and surgical management of invasive lobular breast carcinoma.

MR-Guided Interventions of the Breast

Techniques and instrumentation are now widely available that enable interventional MR-guided preoperative needle localization and lesion marking. Minimally invasive MR-guided core biopsy techniques have been demonstrated but remain limited for small lesions and will be facilitated by the development of biopsy instruments that can be directly visualized using MR imaging. MR-guided tumor ablation is beginning to be evaluated in a few centers. It holds promise as new treatment modality in the continuing trend toward greater breast conservation in the local therapy of breast cancer. Further studies are needed to document the ability of MR-guided ablation to control the margins of a tumor as effectively as surgery. Patients with an extensive in situ intra-ductal component may pose a significant hurdle because the extent of ductal carcinoma in situ maybe underestimated on breast MR images. Ultimately, the success of MR-guided thermal ablation depends on the ability of MR imaging to map the extent of heating during the procedure so that the procedure can be performed to achieve complete control of the tumor margins. It is unfortunate that the conventional method for MR thermometry--the proton resonance frequency shift method--does not work in fat or in voxels with a mix of fat and glandular tissue and, hence, has limited applicability in the breast. Other methods, including measurement of T1 and T2, are being investigated as alternatives.

Additional breast lesions in patients eligible for breast-conserving therapy by MRI: Impact on preoperative management and potential benefit of computerised analysis

This study was conducted to assess the incidence and impact of additional findings from magnetic resonance imaging (MRI) on the workup of patients eligible for breast-conserving therapy (BCT) and to optimise the specificity of further workup by combining radiological reading with computerised analysis. One hundred and sixteen patients eligible for BCT underwent preoperative MRI where the gold standard was histology or follow-up (median 35 months, range 23-48). The incidence of additional findings and impact on treatment (wider excision/conversion to mastectomy) were assessed. The specificity of referral to further workup was also assessed without and with computerised analysis. Additional findings from MRI occurred in 41% of patients, requiring workup in 78%. In 22% the findings were malignant, causing change in treatment. Specificity was 33% (10/30) for radiological reading alone, and 97% (29/30) combined with computer analysis. Our findings show that additional findings preoperative MRI required workup in approximately one-third of patients and we suggest that combining radiological reading with computer analysis has the potential to accurately exclude benign lesions from further workup.

Clinical Experience with MRI-Guided Vacuum-Assisted Breast Biopsy

OBJECTIVE

The objective of our study was to evaluate a new commercially available method of MRI-guided vacuum-assisted breast biopsy using an open coil and a closed 1.5-T scanner.

MATERIALS AND METHODS

Consecutive MRI-guided vacuum-assisted breast biopsies of 38 lesions in 28 women performed between May and September 2003 at two practice sites in the United States were retrospectively reviewed. Lesion characteristics including size, morphology, and enhancement were recorded. Times to perform each procedure, defined as the time from the start of the first localizing scan to the final scan after biopsy, were recorded. Histologic results for all lesions were obtained, and surgical, imaging, or clinical follow-up was performed.

RESULTS

Enhancing masses and foci ranged from 2.5 to 19 mm. Nonmasslike enhancements ranged from 6 to 70 mm. All 38 biopsies (100%) were technically successful, and no complications were associated with any of the biopsy procedures. The average time to perform the 19 single-site MRI-guided procedures was 38 min (range, 23-57 min). The 11 multiple-site biopsies performed in a single breast averaged 59 min (range, 51-68 min), and eight bilateral biopsies averaged 64 min (range, 46-80 min). Histologic results from vacuum-assisted breast biopsy revealed malignancy in 14 lesions (37%), atypical ductal hyperplasia in two lesions (5%), and benign findings in 22 lesions (58%). One of two lesions with atypical ductal hyperplasia was upgraded to ductal carcinoma in situ after surgery, for an overall cancer yield of 40% (15/38).

CONCLUSION

This new method of MRI-guided vacuum-assisted breast biopsy is a safe, effective, and time-efficient means of MRI-guided tissue sampling.

Rates of reexcision for breast cancer after magnetic resonance imaging-guided bracket wire localization

BACKGROUND

We performed this study to determine rates of close or transected cancer margins after magnetic resonance imaging-guided bracket wire localization for nonpalpable breast lesions.

STUDY DESIGN

Of 243 women undergoing MRI-guided wire localizations, 26 had MRI bracket wire localization to excise either a known cancer (n = 19) or a suspicious MRI-detected lesion (n = 7). We reviewed patient age, preoperative diagnosis, operative intent, mammographic breast density, MRI lesion size, MRI enhancement curve and morphology, MRI Breast Imaging Reporting and Data System (BI-RADS) assessment code, number of bracket wires, and pathology size. We analyzed these findings for their relationship to obtaining clear margins at first operative excision.

RESULTS

Twenty-one of 26 (81%) patients had cancer. Of 21 patients with cancer, 12 (57%) had negative margins at first excision and 9 (43%) had close/transected margins. MRI size > or = 4 cm was associated with a higher reexcision rate (7 of 9, 78%) than those < 4 cm (2 of 12, 17%) (p = 0.009). MRI BI-RADS score, enhancement curve, morphology, and preoperative core biopsy demonstrating ductal carcinoma in situ (DCIS) were not predictive of reexcision. The average number of wires used for bracketing increased with lesion size, but was not associated with improved outcomes. On pathology, cancer size was smaller in patients with negative margins (12 patients, 1.2 cm) than in those with close/transected margins (9 patients, 4.6 cm) (p < 0.001). Reexcision was based on close/transected margins involving DCIS alone (6, 67%), infiltrating ductal carcinoma and DCIS (2, 22%), or infiltrating ductal carcinoma alone (1, 11%). Reexcision pathology demonstrated DCIS (3, 33%), no residual cancer (5, 55%), and 1 patient was lost to followup (1, 11%). Interestingly, cancer patients who required reexcision were younger (p = 0.022), but breast density was not associated with reexcision.

CONCLUSIONS

To our knowledge, this is the first report of MRI-guided bracket wire localization. Patients with MRI-detected lesions less than 4 cm had clear margins at first excision; larger MRI-detected lesions were more likely to have close/transected margins. Reexcision was often because of DCIS and was the only pathology found at reexcision, perhaps because MRI is more sensitive for detecting invasive carcinoma than DCIS.

Clinically and mammographically occult breast lesions on MR images: potential effect of computerized assessment on clinical reading

PURPOSE

To investigate if and how computerized analysis complements characterization of breast lesions with clinical reading at magnetic resonance imaging.

MATERIALS AND METHODS

The institutional review board approved the use of data obtained prospectively and analyzed either prospectively with informed patient consent or retrospectively with waiver of consent. An existing computerized analysis system was retrained with 100 breast lesions (in 78 patients with mean age of 46.5 years) and tested with 136 other lesions (in 113 patients with mean age of 48.9 years; P=.15 for age difference between groups). Seventy-five lesions in the training set were previously rated by one of three radiologists in daily clinical practice. Lesion rating (as benign, probably benign, indeterminate, suspicious, or highly suggestive of malignancy) and probability of malignancy calculated with computerized analysis were included as covariates in logistic regression analysis to obtain a combined model. The performance of the model was compared with that of clinical reading alone in a set of 72 clinically and mammographically occult lesions not used to train the computerized analysis system (in 60 patients with mean age of 43.5 years; P=.09 for age difference between training and testing groups). Receiver operating characteristic (ROC) curves were plotted, and areas under the ROC curves were calculated and compared.

RESULTS

Performance of reading in the clinical setting, as indicated by area under the ROC curve (Az=0.86), was similar to that of computerized analysis (Az=0.85; P=.99). Significant overall improvement in performance was obtained with the combined model (Az=0.91; P=.03). Improvement was accomplished mostly in characterization of lesions rated indeterminate or suspicious by radiologists.

CONCLUSION

Computerized analysis complements clinical reading and makes computer-aided diagnosis feasible. The complementary information has the potential to increase overall performance for clinically and mammographically occult lesions.

An overview of the status of imaging screening technology for breast cancer

With breast cancer incidence rates showing no signs of abating, advances in risk stratification and increasing awareness of cancer control, there is interest in expanding the breast imaging arsenal. Mammography is still the standard of care, and a recent meta-analysis of seven large studies supports its value as a screening tool. There is, however, clear need for improved sensitivity and specificity. Imaging of function, metabolism and molecular activity in breast tissue is of potential benefit in addressing these issues. In this article we provide an overview of the current methods of imaging in breast cancer, including mammography, ultrasound, digital mammography, magnetic resonance, positron emission tomography and magnetic resonance spectroscopy. Screening and surveillance should, ideally, be tailored to an individual's cancer risk and breast tissue. Current evidence questions the recent move toward magnetic resonance imaging as a single or multimodality strategy for breast cancer screening. In a high-risk group, the cost effectiveness of technical innovations may be justified.

Optimal management of ductal carcinoma in situ of the breast

Ductal carcinoma in situ (DCIS) represents a breast lesion that is diagnosed with increasing frequency, mainly due to the wide use of screening mammography. Today, DCIS comprises 15-25% of all breast cancers detected at population screening programs. Consequently, the concepts of properly managing such patients assume a greater importance in everyday practice. Mammographically detected microcalcifications are the most common presentation of DCIS. Despite recent technological advances (including Stereotactic-guided directional vacuum-assisted biopsy), mammographically guided wire biopsy remains the "gold-standard" for obtaining a histological diagnosis in patients with non-palpable, mammographically detected DCIS. Management options include mastectomy, local excision combined with radiation therapy, and local excision alone. Given that DCIS is a heterogeneous group of lesions rather than a single entity, and because patients have a wide variety of personal needs that must be addressed during treatment selection, it is obvious that no single approach will be appropriate for all forms of DCIS or for all patients. Careful patient selection is of key importance in order to achieve the best results in the management of the individual patient with DCIS. Axillary lymph node dissection is unnecessary in the treatment of pure DCIS, but it is indicated when microinvasion is present. In these cases, sentinel lymph node biopsy may be an excellent alternative. In the NSABP B-24 trial, tamoxifen reduced both the invasive and non-invasive breast cancer events in either breast by 37%. Nearly all patients who develop a non-invasive recurrence following breast-sparing surgery are cured with mastectomy, and approximately 75% of those with an invasive recurrence are salvaged. Selected patients initially treated by lumpectomy alone may also undergo breast-conservation therapy at the time of relapse according to the same strict guidelines of tumor margin clearance required for the primary lesion; radiation therapy should be given following local excision. The use of systemic therapy in patients with invasive recurrence should be based on standard criteria for invasive breast cancer.

Changes in the surgical management of patients with breast carcinoma based on preoperative magnetic resonance imaging

BACKGROUND

Breast magnetic resonance imaging (MRI) is a developing technique for the evaluation of patients with primary breast carcinoma. The authors assessed the impact of preoperative breast MRI on surgical management.

METHODS

The current study was a retrospective review of 267 patients with primary breast tumors who had MRI studies prior to undergoing definitive surgery.

RESULTS

Two hundred sixty-seven patients with invasive breast carcinoma who had preoperative breast MRI studies and had complete clinical, radiologic, and pathologic data available were identified and formed the basis of this analysis. The overall sensitivity of MRI for detecting primary, intact breast tumors was 95%. Planned surgical management was altered in 69 of 267 patients (26%); and, in 49 of those patients (71%), there was pathologic verification of malignancy in the surgical specimen that confirmed the need for wider or separate excision or mastectomy. Forty-four of 267 patients (16.5%) had conversion of planned breast conservation to mastectomy. In a univariate analysis, change in management was associated significantly with histology; management was altered in 11 of 24 lobular tumors (46%) compared with 58 of 243 ductal tumors (24%; P = 0.02).

CONCLUSIONS

Breast MRI was very sensitive for the detection of primary, intact, invasive breast carcinoma and improved local staging in almost 20% of patients. Preoperative breast MRI studies may be particularly useful in surgical planning for and management of patients with lobular carcinoma.

Treatment of invasive breast carcinoma with ultrasound-guided radiofrequency ablation

BACKGROUND

Radiofrequency ablation (RFA) is a minimally invasive thermal ablation technique. This study reports the safety and efficacy of RFA as a minimally invasive strategy for breast cancers <3 cm diameter in postmenopausal women.

METHODS

Twenty-two postmenopausal women (aged 60 years or older) with clinical T-1N0 core biopsy proven breast cancers were studied. Thermocoagulation was undertaken using a sonographically guided RF probe under local anesthesia and sedation. The ablated tumor was resected between 1 and 2 weeks later. Endpoints were technical success, completeness of tumor kill, marginal clearance, skin damage, and patient reports of pain and procedural acceptability.

RESULTS

The procedure was well tolerated and cosmesis was excellent. Pathology revealed a central ablation zone surrounded by hyperemia. Coagulative necrosis was complete in 19 of 22 patients. Disease at the ablation zone margin was found in 3 patients and 5 patients had disease distant to the ablation zone consisting of multifocal tumors (2), in-transit metastasis (1), and extensive ductal carcinoma in situ with microinvasive carcinoma (2). Ninety-five percent of patients would be willing to have RFA again.

CONCLUSIONS

Radiofrequency ablation can be safely applied in an outpatient setting with acceptable patient tolerance. By itself, RFA cannot be considered effective local therapy. Trials to evaluate RFA complemented with breast irradiation are justified.

A manipulator system for 14-gauge large core breast biopsies inside a high-field whole-body MR scanner

PURPOSE

To investigate a robotic manipulator system for MR-guided breast biopsies inside a 1.5 T whole-body magnet.

MATERIALS AND METHODS

Fourteen patients with suspicious breast lesions (diameter 18.6 +/- 12 mm) underwent biopsy. Patients with malignant findings underwent surgery afterwards and the histologic findings between biopsy and surgery were correlated.

RESULTS

In five patients biopsy findings were histopathologically confirmed following open surgery. One tubular carcinoma was missed; one invasive cancer was underestimated. Seven patients with benign findings are still in the follow-up period.

CONCLUSION

The study demonstrates the feasibility to perform breast biopsies inside the magnet of a whole-body MR scanner by using a manipulator system.

MR imaging of the ipsilateral breast in women with percutaneously proven breast cancer

OBJECTIVE

The purpose of this study was to review MR imaging findings in the ipsilateral breast in women with percutaneously proven breast cancer.

MATERIALS AND METHODS

Retrospective review was performed of records of 70 consecutive women with percutaneously proven unilateral breast cancer who were considered candidates for breast conservation surgery and who had preoperative MR imaging of the ipsilateral breast. MR images and medical records were reviewed.

RESULTS

MR imaging identified mammographically and clinically occult cancer other than the index lesion in the ipsilateral breast in 19 women (27%), including infiltrating cancer in 11 women (16%) and ductal carcinoma in situ in eight women (11%). These additional sites of cancer were in the same quadrant as the index cancer in 14 women (20%), in a different quadrant in three women (4%), and in both the same and different quadrants in two women (3%). Additional sites of cancer were more likely in women with, rather than in those without, a family history of breast cancer (42% vs 14%, p < 0.02) and in women whose index cancer was infiltrating lobular rather than other histologies (55% vs 22%, p < 0.06). In 17 women (24%), MR imaging detected ipsilateral lesions that were benign. Changes due to prior percutaneous biopsy were infrequently observed on MR images and included a clip in 12 women (17%) and a small hematoma in two women (3%).

CONCLUSION

MR imaging identified additional sites of ipsilateral cancer in 27% of women with percutaneously proven breast cancer. The yield was highest in women with a family history of breast cancer or infiltrating lobular histology in the index cancer. Change after biopsy was infrequent and did not interfere with the MR imaging interpretation.