Overview of the role of pre-operative breast MRI in the absence of evidence on patient outcomes

The impact of preoperative breast MRI on the therapeutic management of breast cancer patients

BACKGROUND

The role of preoperative breast MRI to evaluate the extent of disease in breast cancer patients is considered controversial. We aimed at assessing the effect of breast MRI on the management of newly diagnosed breast cancer.

MATERIALS

A retrospective review of 202 consecutively seen patients who were newly diagnosed with breast cancer and who underwent preoperative breast MRIs at Assuta Ashdod between June 1, 2017, and June 1, 2020. Data included discovering suspicious lesions by conventional imaging, MRI findings, and surgical pathology results. This was analyzed to determine whether the MRI changed the management and whether it had a justified or unjustified effect on the treatment.

RESULTS

The mean age was 54.51 (standard deviation, 11.34 years). Breast MRI revealed additional findings in 56 % of patients and modified therapeutic management in 32 % of the cases evaluated, having a justified effect in 87.6 %. Patients with changed management had a statistically significantly higher mastectomy rate (36 %) than those who did not (14 %). No statistically significant association was found between independent variables such as breast density, tumor location on the breast, type of tumor, patient's demographic information, etc. And whether MRI findings changed the initial treatment plan.

CONCLUSIONS

MRI played an essential role in the preoperative staging of breast cancer in our study, modifying therapeutic planning in approximately one-third of the cases and having a justified effect on most of them. We, therefore, support preoperative breast MRI in newly diagnosed breast cancer patients.

MRI Features of Synchronous Masses in Known Breast Cancer Patients in Predicting Benign Versus Malignant Lesions: A Case Based Review at Tertiary Care Cancer Hospital

Sara RehmanObjectives  The purpose of this study was to determine the diagnostic accuracy of breast magnetic resonance imaging (MRI) in classifying incidental satellite masses in biopsy-proven breast cancer patients as benign or malignant masses and assessing its impact on surgical management of these patients. We also analyzed the incidence of MRI-detected lesions, which were thereafter assessed with second look ultrasound (US). Materials and Methods  A retrospective study was performed on breast cancer patients presenting from August 01, 2016 to July 31, 2019, with satellite masses seen on base line MRI. Satellite masses were classified as benign and malignant based on MRI features of shape, margin, T2-weighted imaging signals, internal enhancement pattern, enhancement kinetic curves, and diffusion restriction. This was compared with results of histopathological examination. The number of MRI-detected lesions, location of the satellite mass, and type of surgery were also documented. Results  Out of 400 breast cancer patients undergoing MRI breast, 115 patients had multiple masses. Histopathological diagnosis was available for 73 patients; and a total of 93 satellite masses were evaluated. There was evidence of additional masses on second look ultrasound in 21 patients. Of 72 masses classified as malignant on MRI, 58 showed malignant pathological outcome; while out of 21 masses characterized as benign on MRI, 18 turned out to be benign on histopathology. A statistically significant association was found between MRI features and pathological outcome of satellite masses ( p  = 0.001). The sensitivity, specificity, positive and negative predictive values, and accuracy were 95%, 56%, 80.56%, 85.7% and 81.7%, respectively. Based on these findings, modified radical mastectomy (MRM)/mastectomy was done for 42 patients, 5 patients underwent lumpectomy limited to a single tumor, extended resection done for 14 patients, 5 underwent bilateral breast conservation surgery (BCS), BCS for contralateral breast done for 4 patients undergoing ipsilateral MRM/mastectomy, and bilateral MRM/mastectomies were performed for 2 patients. One patient was lost to follow up. Conclusion  Breast MRI is the most sensitive modality for the assessment of breast cancer and plays an essential role in the detection of additional tumor foci. These findings can modify the surgical approach in these patients. However, considering the low specificity, biopsy of satellite masses is imperative to determine the most appropriate surgical plan.

Clinical utility of MRI in the neoadjuvant management of early-stage breast cancer

BACKGROUND

With the increasing use of neoadjuvant treatment (NAT) for patients with early-stage breast cancer (ESBC), adequate clinical staging is essential to inform treatment. While the use of MRI with NAT has been proposed to help with accuracy of pre-treatment clinical staging, its impact in clinical practice remains controversial.

METHODS

A prospective institutional database of patients with ESBC treated with NAT between May 2012 and December 2020 was analyzed in order to compare the management of patients who received an MRI prior to NAT to those who did not. The indications for MRI and correlation of MRI findings to conventional breast imaging were evaluated. The impact of MRI on management was compared between the MRI and non-MRI groups.

RESULTS

A total of 530 patients met inclusion criteria. Of these, 186 (35.1%) had an MRI and 344 (64.9%) did not. The most frequent indication for MRI was the determination of disease extent (54.5%). Patients who had an MRI prior to neoadjuvant treatment were significantly more likely to be younger (47 years versus 57 years; p < 0.001) and have multifocal disease (32.3% versus 22.1%; p < 0.05). When compared to conventional imaging, MRI reported a greater extent of disease in the breast (37.6%), more nodal involvement (18.8%), and multifocal disease (15.1%). Additional diagnostic interventions were advised in 52.2% of patients who underwent MRI. Rates of mastectomies were greater in the MRI group (80.0% versus 58.9%; p < 0.05) in addition to more axillary dissections (28.0% versus 17.4%; p < 0.01). Rates of locoregional recurrences were low in both groups, with similar disease-free survival outcomes at 5 years.

CONCLUSION

MRI identified significantly more disease in contrast to conventional imaging and lead to more aggressive surgical management. Prospective studies evaluating the role of MRI before NAT and its impact on long-term outcomes are needed.

Diagnostic efficacy of contrast-enhanced breast MRI versus X-ray mammography in women with different degrees of breast density

BACKGROUND

Detection of breast cancer in women with high breast densities is a clinical challenge.

PURPOSE

To study the influence of different degrees of breast density on the sensitivity of contrast-enhanced breast magnetic resonance imaging (CE-BMRI) versus X-ray mammography (XRM).

MATERIAL AND METHODS

We performed an additional analysis of two large Phase III clinical trials (G1; G2) which included women with histologically proven breast cancers, called "index cancers." Additional cancers were detected during image reading. We compared the sensitivity of CE-BMRI and XRM in women with different breast densities (ACR A→D; Version 5). For each study, six blinded readers evaluated the images. Results are given as the "Median Reader."

RESULTS

A total of 774 patients were included, 169 had additional cancers. While sensitivity of CE-BMRI for detecting all index cancers was independent of breast density (ACR A→D) (G1: 83%→83%; G2: 91%→91%) the sensitivity of XRM declined (ACR A→D) (G1: 79%→62%; G2: 82%→64%). Thus, the sensitivity difference between both imaging modalities in ACR A breasts of 3% (G1) and 9% (G2) increased to 21% (G1) and 26% (G2) in ACR D breasts. Sensitivity of CE-BMRI for detecting at least one additional cancer increased with increasing breast density (ACR A→D) (G1: 50%→73%, G2: 57%→81%). XRM's sensitivity decreased (G1: 34%→20%) or remained stable (G2: 24%→25%).

CONCLUSION

CE-BMRI showed significantly higher sensitivity compared to XRM.

Diffusion-weighted Imaging Allows for Downgrading MR BI-RADS 4 Lesions in Contrast-enhanced MRI of the Breast to Avoid Unnecessary Biopsy

PURPOSE

Diffusion-weighted imaging with the calculation of an apparent diffusion coefficient (ADC) has been proposed as a quantitative biomarker on contrast-enhanced MRI (CE-MRI) of the breast. There is a need to approve a generalizable ADC cutoff. The purpose of this study was to evaluate whether a predefined ADC cutoff allows downgrading of BI-RADS 4 lesions on CE-MRI, avoiding unnecessary biopsies.

EXPERIMENTAL DESIGN

This was a retrospective, multicentric, cross-sectional study. Data from five centers were pooled on the individual lesion level. Eligible patients had a BI-RADS 4 rating on CE-MRI. For each center, two breast radiologists evaluated the images. Data on lesion morphology (mass, non-mass), size, and ADC were collected. Histology was the standard of reference. A previously suggested ADC cutoff (≥1.5 × 10-3 mm2/second) was applied. A negative likelihood ratio of 0.1 or lower was considered as a rule-out criterion for breast cancer. Diagnostic performance indices were calculated by ROC analysis.

RESULTS

There were 657 female patients (mean age, 42; SD, 14.1) with 696 BI-RADS 4 lesions included. Disease prevalence was 59.5% (414/696). The area under the ROC curve was 0.784. Applying the investigated ADC cutoff, sensitivity was 96.6% (400/414). The potential reduction of unnecessary biopsies was 32.6% (92/282).

CONCLUSIONS

An ADC cutoff of ≥1.5 × 10-3 mm2/second allows downgrading of lesions classified as BI-RADS 4 on breast CE-MRI. One-third of unnecessary biopsies could thus be avoided.

Practical consensus recommendations regarding the management of sentinel lymph node issues in early breast cancer

Axillary lymph node involvement is a very important poor prognostic factor in the clinical staging and management of breast cancer patients. Traditionally, axillary lymph node dissection (ALND) has been used for determining the status of the axillary lymph nodes. More recently the sentinel lymph node biopsy (SLNB) procedure has gained wider acceptance as the standard of care, having the advantage of being less invasivewhile providing good accuracy. This expert group used data from published literature, practical experience and opinion of a large group of academic oncologists to arrive at these practical consensus recommendations in regards with the use of the two different procedures and other issues in patients with early breast cancer for the benefit of community oncologists.

The Value of Patient and Tumor Factors in Predicting Preoperative Breast MRI Outcomes

Purpose

To identify patient and tumor features that predict true-positive, false-positive, and negative breast preoperative MRI outcomes.

Materials and Methods

Using a breast MRI database from a large regional cancer center, the authors retrospectively identified all women with unilateral breast cancer who underwent preoperative MRI from January 2005 to February 2015. A total of 1396 women with complete data were included. Patient features (ie, age, breast density) and index tumor features (ie, type, grade, hormone receptor, human epidermal growth factor receptor type 2/neu, Ki-67) were extracted and compared with preoperative MRI outcomes (ie, true positive, false positive, negative) using univariate (ie, Fisher exact) and multivariate machine learning approaches (ie, least absolute shrinkage and selection operator, AutoPrognosis). Overall prediction performance was summarized using the area under the receiver operating characteristic curve (AUC), calculated using internal validation techniques (bootstrap and cross-validation) to account for model training.

Results

At the examination level, 181 additional cancers were identified among 1396 total preoperative MRI examinations (median patient age, 56 years; range, 25-94 years), resulting in a positive predictive value for biopsy of 43% (181 true-positive findings of 419 core-needle biopsies). In univariate analysis, no patient or tumor feature was associated with a true-positive outcome (P > .05), although greater mammographic density (P = .022) and younger age (< 50 years, P = .025) were associated with false-positive examinations. Machine learning approaches provided weak performance for predicting true-positive, false-positive, and negative examinations (AUC range, 0.50-0.57).

Conclusion

Commonly used patient and tumor factors driving expert opinion for the use of preoperative MRI provide limited predictive value for determining preoperative MRI outcomes in women. Supplemental material is available for this article. © RSNA, 2020See also the commentary by Grimm in this issue.

Associations of preoperative breast magnetic resonance imaging with subsequent mastectomy and breast cancer mortality

PURPOSE

To examine associations between pre-operative magnetic resonance imaging (MRI) use and clinical outcomes among women undergoing breast-conserving surgery (BCS) with or without radiotherapy for early-stage breast cancer.

METHODS

We identified women from the Surveillance, Epidemiology, and End Results-Medicare dataset aged 67-94 diagnosed during 2004-2010 with stage I/II breast cancer who received BCS. We compared subsequent mastectomy and breast cancer mortality with versus without pre-operative MRI, using Cox regression and competing risks models. We further stratified by receipt of radiotherapy for subgroup analyses.

RESULTS

Our sample consisted of 24,379 beneficiaries, 4691 (19.2%) of whom received pre-operative MRI. Adjusted rates of subsequent mastectomy and breast cancer mortality were not significantly different with and without MRI: 3.2 versus 4.1 per 1000 person-years [adjusted hazard ratio (AHR) 0.92; 95% confidence interval (CI) 0.70-1.19] and 5.3 versus 8.7 per 1000 person-years (AHR 0.89; 95% CI 0.73-1.08), respectively. In subgroup analyses, women receiving BCS plus radiotherapy had similar rates of subsequent mastectomy (AHR 1.17; 95% CI 0.84-1.61) and breast cancer mortality (AHR 1.00; 95% CI 0.80-1.24) with versus without MRI. However, among women receiving BCS alone, MRI use was associated with lower risks of subsequent mastectomy (AHR 0.60; 95% CI 0.37-0.98) and breast cancer mortality (AHR 0.57; 95% CI 0.36-0.92).

CONCLUSIONS

Pre-operative MRI was associated with improved outcomes among older women with breast cancer receiving BCS alone, but not among those receiving BCS plus radiotherapy. Further research is needed to identify appropriate settings for which MRI may be helpful.

Accuracy of Ultrasound for Preoperative Assessment of Tumor Size in Patients With Newly Diagnosed Breast Cancer: Is It Affected by the Background Parenchymal Echotexture?

OBJECTIVES

To assess the impact of the background parenchymal echotexture on the accuracy of tumor size estimation using breast ultrasound (US).

METHODS

A total of 140 women with newly diagnosed invasive breast cancer from January 2014 to December 2015 were enrolled in this study. Two radiologists retrospectively reviewed US images in consensus for background parenchymal echotexture interpretation. The maximum tumor diameter from static images was recorded. Tumor size measurements were considered as having agreement with histologic results if they were within ±5 mm compared to the pathologic size. The relationship between the accuracy of tumor size measurement by the background parenchymal echotexture and clinicopathologic characteristics was evaluated.

RESULTS

Of these 140 patients, 77 (55.0%) showed a homogeneous background parenchymal echotexture, whereas 63 (45.0%) showed a heterogeneous echotexture. The mean tumor size was 1.9 cm (range, 0.5-4.9 cm). The overall accuracy of tumor size measurement was 76.4% (104 of 140). Tumors of women with a homogeneous background parenchymal echotexture were more accurately measured than those of women with a heterogeneous echotexture (87.0% versus 63.5%; P = .001). Tumors with a small size (<2 cm; P = .018) and ductal carcinoma in situ-negative (P = .031), human epidermal growth factor receptor 2 (HER2)-negative (P = .053), and triple-negative (P = .016) types were also more accurately measured. The independent factors associated with inaccurate tumor size measurement were a heterogeneous background parenchymal echotexture, a large tumor size, and the HER2-enriched type (P < .05).

CONCLUSIONS

The background parenchymal echotexture affected the accuracy of tumor size estimation using breast US. Invasive breast cancers with large (≥2 cm) tumors and the HER2-enriched type showed significantly lower breast US accuracy compared to others.

Understanding indications and defining guidelines for breast magnetic resonance imaging

Magnetic resonance imaging (MRI) of the breast is the most sensitive imaging modality for detecting cancer. With improved scan resolution and correctly applied clinical indications, the specificity of breast MRI has markedly improved in recent years. Current literature indicates an overall sensitivity for breast MRI of 98% - 100% and specificity of 88%. By comparison, the sensitivity and specificity for mammography is in the region of 71% and 98%, respectively. In particular, the very high negative predictive value (NPV) of breast MRI, which approaches 100%, is hugely useful in establishing absence of disease. Furthermore, the ability to accurately delineate viable cancer by way of combining both morphological and functional (contrast enhancement) capabilities means that MRI is the best tool we have in terms of local cancer staging and identifying residual or recurrent disease. The high NPV also means that breast MRI is uniquely capable of ruling out cancer or high-grade ductal carcinoma in situ in appropriate circumstances. I hope that the following guidelines that are based on those of the American College of Radiology and the European Society of Breast Imaging in addition to multiple review articles will provide some assistance to radiologists in terms of the correct indications for breast MRI. There are few formal guidelines in South Africa for the usage of breast MRI. In fact, there is a general paucity of guidelines in the international radiology world. The role of breast MRI in high-risk screening and identification of the primary in occult breast cancer is universally accepted. Thereafter, there is little consensus. By using some general guidelines, and bringing MRI into the discussion of multidisciplinary breast cancer management, good clinical practice and consistent decision-making can be established.

Frequency and characteristics of additionally detected ipsilateral breast lesions following recall at screening mammography

PURPOSE

To determine the frequency and outcome of additionally detected ipsilateral breast abnormalities following recall at screening mammography.

METHODS AND MATERIALS

We included a consecutive series of 130,338 screening mammograms obtained between January 1, 2014 and January 1, 2016. During 2-year follow-up, clinical data were collected of all recalls. Women with a bilateral recall (115) and women recalled for multiple lesions in one breast (165) were excluded from the analyses. Screening outcome parameters were determined for recalled women with or without evaluation of additional ipsilateral breast abnormalities following recall.

RESULTS

A total of 3995 women were recalled (recall rate, 3.1%). In 258 (6.4%) of these women, another lesion was detected in the ipsilateral breast than the one for which she had been recalled. Biopsy was more frequently performed of additionally detected ipsilateral lesions than of recalled lesions (55.8% (144/258)) versus 39.7% (1375/3457), (p < 0.001)). The proportion of malignancy in recalled lesions and additionally detected lesions was comparable (21.5% (743/3457) versus 19.0% (49/258), p = 0.34). Of all 144 biopsies of additionally detected ipsilateral lesions, 9 revealed a synchronous tumour in addition to a malignant recalled lesion, and 33 biopsies revealed multicentric or multifocal tumours. In 5 women, the recalled lesion turned out to be benign, whereas the additional lesion in a different quadrant was malignant at biopsy. A total of 97 biopsies showed benign findings.

CONCLUSION

A substantial proportion of women are analyzed for additional ipsilateral breast lesions following recall. These lesions are more frequently biopsied than recalled lesions, but have a comparable probability of being malignant. The majority of additionally detected cancerous lesions are part of multifocal or multicentric malignancies.

Preoperative Breast Magnetic Resonance Imaging Use by Breast Density and Family History of Breast Cancer

BACKGROUND

Use of preoperative breast magnetic resonance imaging (MRI) among women with a new breast cancer has increased over the past decade. MRI use is more frequent in younger women and those with lobular carcinoma, but associations with breast density and family history of breast cancer are unknown.

MATERIALS AND METHODS

Data for 3075 women ages >65 years with stage 0-III breast cancer who underwent breast conserving surgery or mastectomy from 2005 to 2010 in the Breast Cancer Surveillance Consortium were linked to administrative claims data to assess associations of preoperative MRI use with mammographic breast density and first-degree family history of breast cancer. Multivariable logistic regression estimated adjusted odds ratios (OR) and 95% confidence intervals (95% CI) for the association of MRI use with breast density and family history, adjusting for woman and tumor characteristics.

RESULTS

Overall, preoperative MRI use was 16.4%. The proportion of women receiving breast MRI was similar by breast density (17.6% dense, 16.9% nondense) and family history (17.1% with family history, 16.5% without family history). After adjusting for potential confounders, we found no difference in preoperative MRI use by breast density (OR = 0.95 for dense vs. nondense, 95% CI: 0.73-1.22) or family history (OR = 0.99 for family history vs. none, 95% CI: 0.73-1.32).

CONCLUSIONS

Among women aged >65 years with breast cancer, having dense breasts or a first-degree relative with breast cancer was not associated with greater preoperative MRI use. This utilization is in keeping with lack of evidence that MRI has higher yield of malignancy in these subgroups.

A survey by the European Society of Breast Imaging on the utilisation of breast MRI in clinical practice

OBJECTIVES

While magnetic resonance imaging (MRI) is considered a helpful diagnostic tool in breast imaging, discussions are ongoing about appropriate protocols and indications. The European Society of Breast Imaging (EUSOBI) launched a survey to evaluate the utilisation of breast MRI in clinical practice.

METHODS

An online survey reviewed by the EUSOBI board and committees was distributed amongst members. The questions encompassed: training and experience; annual breast MRI and MRI-guided-intervention workload; examination protocols; indications; reporting habits and preferences. Data were summarised and subgroups compared using χ² test.

RESULTS

Of 647 EUSOBI members, 177 (27.4%) answered the survey. The majority were radiologists (90.5%), half of them based in academic centres (51.9%). Common indications for MRI included cancer staging, treatment monitoring, high-risk screening and problem-solving, and differed significantly between countries (p≤0.03). Structured reporting and BI-RADS were mostly used. Breast radiologists with ≤10 years of experience preferred inclusion of additional techniques, such as T2/STIR (p=0.03) and DWI (p=0.08) in the scan protocol. MRI-guided interventions were performed by a minority of participants (35.4%).

CONCLUSIONS

The utilisation of breast MRI in clinical practice is generally in line with international recommendations. There are substantial differences between countries. MRI-guided interventions and functional MRI parameters are not widely available.

KEY POINTS

• MRI is commonly used for the detection and characterisation of breast lesions. • Clinical practice standards are generally in line with current recommendations. • Standardised criteria and diagnostic categories (mainly BI-RADS) are widely adopted. • Younger radiologists value additional techniques, such as T2/STIR and DWI. • MRI-guided breast biopsy is not widely available.

Assessing the Effect of Lifetime Contralateral Breast Cancer Risk on the Selection of Contralateral Prophylactic Mastectomy for Unilateral Breast Cancer

INTRODUCTION

Contralateral prophylactic mastectomy (CPM) rates are rising, with fear implicated as a contributing factor. This study used a contralateral breast cancer (CBC) risk stratification tool to assess whether the selection of CPM is reflective of future CBC risk.

PATIENTS AND METHODS

This retrospective study evaluated 404 women with unilateral breast cancer treated with breast conservation, unilateral mastectomy, or bilateral mastectomy within a single multidisciplinary clinic. Women were evaluated by the Manchester risk tool to calculate lifetime CBC risk. Logistic regression analysis was used to evaluate whether CBC risk was associated with CPM, and the clinical rationale for prophylactic mastectomy justification was recorded.

RESULTS

Sixty-two percent underwent breast conservation, 18% unilateral mastectomy, and 20% bilateral mastectomy. In the CPM cohort, 36% had > 20% calculated lifetime CBC risk. In the invasive cohort, younger age (odds ratio 2.65, P < .0001) and genetic mutation positivity (odds ratio 35.39, P = .019) independently predicted CPM. Other contributing factors included benign contralateral breast findings (29%) and recommendations against breast conservation due to disease burden (28%). Six percent selected CPM as a result of an unsubstantiated fear regarding breast cancer.

CONCLUSION

The majority of women (63%) who selected CPM had < 20% CBC risk. In these lower-risk women selecting CPM, factors increasing reasonable fear dominated surgical choice (81% of this subset).

Breast MR imaging for the assessment of residual disease following initial surgery for breast cancer with positive margins

OBJECTIVES

To determine the accuracy of post-operative MR in predicting residual disease in women with positive margins, emphasizing the size thresholds at which residual disease can be confidently identified.

METHODS

This IRB-approved HIPAA-compliant retrospective study included 175 patients with MR after positive margins following initial surgery for breast cancer. Two expert readers independently re-evaluated MR images for evidence of residual disease at the surgical cavity and multifocal/multicentric disease. All patients underwent definitive surgery and MR findings were correlated to histopathology.

RESULTS

139/175 (79.4%) patients had residual disease at surgery. Average overall sensitivity, specificity, PPV and NPV for residual disease at the surgical cavity were 73%, 72%, 91% and 45%, respectively. The readers identified 42/45 (93%, reader 1) and 43/45 (95%, reader 2) patients with residual invasive disease at the cavity of ≥5 mm and 22/22 (100%, both readers) patients with disease ≥10 mm. Average sensitivity, specificity, PPV and NPV for unknown multifocal/multicentric disease were 90%, 96%, 93% and 86%, respectively.

CONCLUSIONS

Post-operative breast MR can accurately depict ≥5-mm residual disease at the surgical cavity and unsuspected multifocal/multicentric disease. These findings have the potential to lead to more appropriate selection of second surgical procedures in women with positive margins.

KEY POINTS

• Post-operative breast MRI accurately defines residual disease of ≥5 mm. • Surgical cavity sensitivities were high for both invasive carcinoma and DCIS. • Post-surgical changes and very small residual disease (<5 mm) may overlap. • Post-operative breast MRI may help planning an accurate re-resection.

Role of magnetic resonance imaging in the planning of breast cancer treatment strategies: comparison with conventional imaging techniques

OBJECTIVE

To assess the role of magnetic resonance imaging (MRI) in the planning of breast cancer treatment strategies.

MATERIALS AND METHODS

The study included 160 women diagnosed with breast cancer, who underwent breast MRI for preoperative staging. Using Pearson's correlation coefficient (r), we compared the size of the primary tumor, as determined by MRI, by conventional imaging (mammography and ultrasound), and in the pathological examination (gold standard). The identification of lesions not identified in previous examinations was also evaluated, as was its influence on treatment planning.

RESULTS

The mean age of the patients was 52.2 years (range, 30-81 years), and the most common histological type was invasive ductal carcinoma (in 60.6% of the patients). In terms of the tumor size determined, MRI correlated better with the pathological examination than did mammography (r = 0.872 vs. 0.710) or ultrasound (r = 0.836 vs. 0.704). MRI identified additional lesions in 53 patients (33.1%), including malignant lesions in 20 (12.5%), which led to change in the therapeutic planning in 23 patients (14.4%).

CONCLUSION

Breast MRI proved to be more accurate than conventional imaging in determining the dimensions of the main tumor and was able to identify lesions not identified by other methods evaluated, which altered the therapeutic planning in a significant proportion of cases.

Impact of value based breast cancer care pathway implementation on pre-operative breast magnetic resonance imaging utilization

BACKGROUND

Bilateral breast magnetic resonance imaging (MRI) is commonly used in the diagnostic workup of breast cancer (BC) to assess extent of disease and identify occult foci of disease. However, evidence for routine use of pre-operative MRI is lacking. Breast MRI is costly and can lead to unnecessary tests and treatment delays. Clinical care pathways (care paths) are value-based guidelines, which define management recommendations derived by expert consensus and available evidence based data. At Cleveland Clinic, care paths created for newly diagnosed BC patients recommend selective use of pre-operative MRI. We evaluated the number of pre-operative MRIs ordered before and after implementing an institution wide BC care paths in April 2014.

METHODS

A retrospective review was conducted of BC cases during the years 2012, 2014, and part of 2015. Patient, tumor and treatment characteristics were collected. Pre-operative MRI utilization was compared before and after care path implementation.

RESULTS

We identified 1,515 BC patients during the study period. Patients were more likely to undergo pre-operative MRI in 2012 than 2014 (OR: 2.77; P<0.001; 95% CI: 1.94-3.94) or 2015 (OR: 4.14; P<0.001; 95% CI: 2.51-6.83). There was a significant decrease in pre-operative MRI utilization between 2012 and 2014 (P<0.001) after adjustment for pre-operative MRIs ordered for care path indications.

CONCLUSIONS

Implementation of online BC care paths at our institution was associated with a decreased use of pre-operative MRI overall and in patients without a BC care path indication, driving value based care through the reduction of pre-operative breast MRIs.

Locoregional treatment of breast cancer in women with and without preoperative magnetic resonance imaging

BACKGROUND

Preoperative magnetic resonance imaging (MRI) use has increased among older women diagnosed with breast cancer. MRI detects additional malignancy, but its impact on locoregional surgery and radiation treatment remains unclear.

METHODS

We examined the associations of preoperative MRI with initial locoregional treatment type (mastectomy, breast conserving surgery [BCS] with radiation therapy [RT], and BCS without RT) and BCS reoperation rates for Surveillance, Epidemiology, and End Results Medicare women diagnosed with stages 0 to III breast cancer from 2005 to 2009 (n = 55,997).

RESULTS

We found no association of initial locoregional treatment of mastectomy (odds ratios [OR], 1.04; 95% confidence intervals, .98 to 1.11) or reoperation after initial BCS (OR, .96; 95% confidence intervals, .89 to 1.03) between women with preoperative MRI (16.2%) compared to women without MRI. However, women with MRI who had initial BCS were more likely to undergo RT (OR, 1.09 [1.02 to 1.16]).

CONCLUSIONS

Preoperative breast MRI in Medicare-enrolled women with stages 0 to III breast cancer was not associated with increased mastectomy. However, in older women with MRI undergoing BCS, there was a greater use of RT.

Routine use of preoperative breast MRI for patients considered for intraoperative radiotherapy

This editorial comments on the study by Tallet et al. which reported on the incidence of ipsilateral second breast cancers (BC) detected by preoperative magnetic resonance imaging (MRI) in patients being considered for intraoperative radiotherapy (IORT). Any second BC was detected in 7% of patients; an ipsilateral BC was detected in 4% of patients, precluding them from IORT. The authors comment that in view of detection of a substantial rate of ipsilateral BCs by preoperative MRI, this exam should be used routinely for staging patients being considered for IORT.

Preoperative Breast Magnetic Resonance Imaging and Contralateral Breast Cancer Occurrence Among Older Women With Breast Cancer

PURPOSE

Preoperative magnetic resonance imaging (MRI) detects occult contralateral breast cancers (CBCs) in women with breast cancer, but the impact of detection on long-term CBC events is unclear. We examined whether MRI use decreases the occurrence of CBCs and the detection of stages II to IV disease among women who develop a CBC.

PATIENTS AND METHODS

Analyzing the SEER-Medicare database, we assessed overall, synchronous (< 6 months after primary cancer diagnosis), and subsequent (ie, metachronous) stage-specific CBC occurrences in women who were diagnosed with stages I and II breast cancer during 2004-2009 and who were observed through 2011.

RESULTS

Among 38,971 women with breast cancer, 6,377 (16.4%) received preoperative MRI. After propensity score matching, and compared with women who did not undergo MRI, preoperative MRI use was significantly associated with a higher synchronous CBC detection rate (126.4 v 42.9 per 1,000 person-years, respectively; hazard ratio, 2.85; P < .001) but a lower subsequent CBC detection rate (3.3 v 4.5 per 1,000 person-years, respectively; hazard ratio, 0.68; P = .002). However, the 5-year cumulative incidence of CBC remained significantly higher among women undergoing MRI compared with those not undergoing MRI (7.2% v 4.0%, respectively; P < .001). The analyses of projected CBC events for 10,000 patients who receive MRI indicated that, after a 5-year follow-up, MRI use would detect an additional 192 in situ CBCs (95% CI, 125 to 279) and 120 stage I CBCs (95% CI, 62 to 193) but would not have a significant impact on stages II to IV CBC occurrences (∼ 6; 95% CI, -21 to 47).

CONCLUSION

An increased synchronous CBC detection rate, attributable to MRI, was not offset by a decrease of subsequent CBC occurrence among older women with early-stage breast cancer, suggesting that preoperative MRI in women with breast cancer may lead to overdiagnosis.

Breast Cancer in the Elderly: Is MRI Helpful?

Appropriate use of magnetic resonance imaging (MRI) in elderly breast cancer (BC) patients remains unclear; we sought to identify the indications and implications of MRI use in our elderly BC population. Women 70 years of age or older at first BC diagnosis with an MRI performed at our institution either perioperatively or in follow-up were included from a prospectively maintained database from 2000 to 2010. Univariate logistic regression was used to test associations with disease identified by MRI only (additional ipsilateral, contralateral, or new cancer) following perioperative MRI. 305 BCs were imaged in 286 patients. 133 were imaged with MRI in the perioperative setting alone, 88 had only follow-up MRIs after BC treatment, and 65 had both. Indications for perioperative MRI include: extent of disease evaluation (181; 91%); occult primary (10; 5%); high-risk screening (5; 3%); and abnormal physical exam with negative conventional imaging (2; 1%). Disease identified by MRI only for occult primary cases was 4/10 (40%; 95% confidence interval: 12.2-73.8%) and 14/181 (7.7%; 95% confidence interval: 4.3-12.6%) for perioperative MRIs performed for extent of disease evaluation. Analysis of imaging and tumor characteristics failed to find significant predictors of disease identified by MRI only. A total of 369 post-treatment follow-up MRIs were performed in 148 patients with a median of 2 MRIs per patient (range 1-8), with seven cases of disease identified by MRI only (1.9%; 95% confidence interval: 0.8-3.9%). MRI had the greatest benefit in women presenting with an occult primary cancer and minimal additional benefit in elderly patients with BC undergoing MRI imaging for extent of disease evaluation or in post-treatment surveillance.

Flexible, 31-Channel breast coil for enhanced parallel imaging performance at 3T

PURPOSE

To design, build, and characterize the performance of a novel 3T, 31-channel breast coil.

METHODS

A flexible breast coil, accommodating all breast sizes while preserving close to unity filling factors in all configurations, was designed and built. Its performance was compared to the performance of the current state-of-the-art, 16 channel breast coil (Sentinelle coil, Hologic, Bedford, MA, USA), in phantoms and in vivo.

RESULTS

Better axilla coverage and lower inter-coil coupling (12% versus 26%, as characterized by the average off-diagonal elements of the noise correlation matrix) was exhibited by our 31-channel coil compared with the 16-channel coil. Breast area signal-to-noise ratio increases of 68% (phantom) and 28% ± 31% (in vivo) were observed when the 31-channel coil was used. For the 31-channel/16-channel arrays, respectively, two-dimensional acceleration factors of left/right × superior/inferior = 4.3 × 2.4 resulted in average g-factors of 1.10/1.68 (in vitro) and 1.28/2.75 (in vivo); acceleration factors of left/right × anterior/posterior = 3.0 × 2.8 resulted in average g-factors of 1.06/1.54 (in vitro) and 1.05/1.12 (in vivo).

CONCLUSION

A high performance breast coil was built; its capabilities were demonstrated in phantom and normal volunteer imaging experiments.

Magnetic resonance imaging in patients with newly diagnosed breast cancer: a review of the literature

The use of magnetic resonance imaging (MRI) in patients with newly diagnosed breast cancer remains controversial. Here we review the current use of breast MRI and the impact of MRI on short-term surgical outcomes and rates of local recurrence. In addition, we address the use of MRI in specific patient populations, such as those with ductal carcinoma in situ, invasive lobular carcinoma, and occult primary breast cancer, and discuss the potential role of MRI for assessing response to neoadjuvant chemotherapy. Although MRI has improved sensitivity compared with conventional imaging, this has not translated into improved short-term surgical outcomes or long-term patient benefit, such as improved local control or survival, in any patient population. MRI is an important diagnostic test in the evaluation of patients presenting with occult primary breast cancer and has shown promise in monitoring response to neoadjuvant chemotherapy; however, the data do not support the routine use of perioperative MRI in patients with newly diagnosed breast cancer. Cancer 2014;120:120:2080-2089. © 2014 American Cancer Society.

Controversies in breast MRI

When used for appropriate indications, breast magnetic resonance imaging (MRI) is a powerful diagnostic tool. However, breast MRI has its share of controversies. These controversies can be a source of confusion for the radiologist or referring physician. This paper addresses 4 breast MRI controversies that we frequently encounter at our university hospital practice: (1) what are the appropriate indications for screening breast MRI? (2) what are the appropriate indications for the use of breast MRI as a problems-solving modality? (3) how does one interpret MRI imaging features that have substantial overlap between benign and malignant conditions? and (4) what are the appropriate indications for preoperative breast MRI? Illustrative case examples are provided.

Evaluation of expert criteria for preoperative magnetic resonance imaging of newly diagnosed breast cancer

Despite 2 randomized trials reporting no reduction in operations or local recurrence at 1 year, preoperative magnetic resonance imaging (MRI) is increasingly used in diagnostic workup of breast cancer. We evaluated 5 utilization criteria recently proposed by experts. Of women (n = 340) newly diagnosed with unilateral breast cancer who underwent bilateral MRI, most (69.4%) met at least 1 criterion before MRI: mammographic density (44.4%), under consideration for partial breast irradiation (PBI) (19.7%), genetic-familial risk (12.9%), invasive lobular carcinoma (11.8%), and multifocal/multicentric disease (10.6%). MRI detected occult malignant lesion or extension of index lesion in 21.2% of index, 3.3% of contralateral, breasts. No expert criterion was associated with MRI-detected malignant lesion, which associated instead with pre-MRI plan of lumpectomy without PBI (48.2% of subjects): Odds Ratio 3.05, 95% CI 1.57-5.91 (p adjusted for multiple hypothesis testing = 0.007, adjusted for index-vs-contralateral breast and covariates). The expert guidelines were not confirmed by clinical evidence.

Preoperative breast MRI and surgical outcomes in elderly women with invasive ductal and lobular carcinoma: a population-based study

Existing evidence suggests that preoperative breast magnetic resonance imaging (MRI) might not improve surgical outcomes in the general breast cancer population. To determine if patients differentially benefit from breast MRI, we examined surgical outcomes-initial mastectomy, reoperation, and final mastectomy rates-among patients grouped by histologic type. We identified women diagnosed with early-stage breast cancer from 2004 to 2007 in the SEER-Medicare dataset. We classified patients as having invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC), mixed ductal/lobular carcinoma (IDLC) or other histologic type. Medicare claims were used to identify breast MRI and definitive surgeries during the initial surgical treatment episode. We used propensity score methods to account for the differential likelihood of exposure to MRI. Of the 20,332 patients who met our inclusion criteria for this study, 12.2 % had a preoperative breast MRI. Patients with ILC as compared to other histologic groups were most likely to receive MRI [OR 2.32; 95 % CI (2.02-2.67)]. In the propensity score-adjusted analyses, breast MRI was associated with an increased likelihood of an initial mastectomy for all patients and among all histologic subgroups. Among patients with ILC, having a breast MRI was associated with lower odds of a reoperation [OR 0.59; 95 % CI (0.40-0.86)], and an equal likelihood of a final mastectomy compared to similar patients without a breast MRI. Overall and among patients with IDC and IDLC, breast MRI was not significantly associated with a likelihood of a reoperation but was associated with greater odds of a final mastectomy. Our study provides evidence in support of the targeted use of preoperative breast MRI among patients with ILC to improve surgical planning; it does not provide evidence for the routine use of breast MRI among all newly diagnosed breast cancer patients or among patients with IDC.

Variability of preoperative breast MRI utilization among older women with newly diagnosed early-stage breast cancer

While magnetic resonance imaging (MRI) is frequently used following breast cancer diagnosis, routine use of breast MRI for preoperative evaluation remains contentious. We identified factors associated with preoperative breast MRI utilization and investigated the variation among physicians. We used the surveillance, epidemiology, and end Results (SEER)-Medicare linked database to analyze the preoperative breast MRI utilization among patients with stage 0, I, or II breast cancer diagnosed between 2002 and 2007. Multilevel logistic regression models were used to identify patient- and physician-level predictors of preoperative MRI utilization. Of 56,743 women with early-stage breast cancer who were treated with surgery and evaluated by a preoperative mammogram and/or ultrasound during the study period, 8.7% (n = 4,913) received preoperative breast MRI. While patient and tumor characteristics did predict preoperative breast MRI utilization, they explained only 15.4% of the variation in utilization rates. Differences in preoperative breast MRI utilization across physicians were large, after controlling patient-level factors and physicians' volumes. Accounting for clustering of patients within individual physicians (n = 3,144), the multilevel logistic regression models explained 36.4% of variation. The median odds ratio of 3.2, corresponding with the median value of the relative odds of receiving preoperative breast MRI between two randomly chosen physicians, indicated a large individual physician effect. Our study found that preoperative breast MRI has been adopted rapidly and variably. Although patient characteristics were associated with preoperative breast MRI utilization, physician practice was a major determinant of whether women received preoperative breast MRI. Future studies should evaluate whether routine use of preoperative breast MRI in newly diagnosed early-stage breast cancer improves clinical outcomes.

The case against routine preoperative breast MRI

In patients with primary breast cancer, preoperative MRI identifies additional foci of tumor in the ipsilateral or contralateral breast that are not evident with standard imaging. Breast cancer patients who are otherwise deemed suitable candidates for breast-conserving surgery might, therefore, be urged to undergo mastectomy or even bilateral mastectomy following staging with preoperative breast MRI. The effect of preoperative breast MRI on clinical end points (rates of ipsilateral breast tumor recurrence) and surgical end points (rates of reoperation) have been assessed in several large studies. These studies indicate that the routine use of preoperative breast MRI is not beneficial. The additional occult foci of tumor detected with preoperative breast MRI seem to either have no clinical significance, or can be adequately treated with radiotherapy and/or systemic therapy. This article reviews these studies and highlights the potential harms associated with the routine use of preoperative MRI in patients with primary breast cancer.

Accuracy of tumour size assessment in the preoperative staging of breast cancer: comparison of digital mammography, tomosynthesis, ultrasound and MRI

PURPOSE

Accurate measurement of breast tumour size is fundamental for treatment planning. We compared the accuracy of digital mammography (DM), digital breast tomosynthesis (DBT), ultrasound (US) and magnetic resonance imaging (MRI) for the preoperative evaluation of breast cancer size.

MATERIALS AND METHODS

We retrospectively reviewed 149 breast cancers in 110 patients who underwent DM, DBT, US and MRI between January 2010 and December 2011, before definitive surgery. The lesions were measured by two radiologists, without knowledge of the final histological examination, considered the gold standard. For each imaging modality, the maximum tumour size was measured to the nearest millimetre; the measurements were considered concordant if they were within ± 5 mm. Pearson's correlation coefficient was calculated for each imaging modality.

RESULTS

The median pathological tumour size was 22.3 mm. MRI and DBT had a level of concordance with pathology of 70% and 66%, respectively, which was higher than that of DM (54%). DBT and MRI measurements had a better correlation with pathological tumour size (R:0.89 and R:0.92, respectively) compared to DM (R:0.83) and US (R:0.77).

CONCLUSIONS

DBT and MRI are superior to DM and US in the preoperative assessment of breast tumour size. DBT seems to improve the accuracy of DM, although MRI remains the most accurate imaging modality for breast cancer extension.

Breast cancer size estimation with MRI in BRCA mutation carriers and other high risk patients

OBJECTIVE

To assess the value of breast MRI in size assessment of breast cancers in high risk patients, including those with a BRCA 1 or 2 mutation. Guidelines recommend invariably breast MRI screening for these patients and therapy is thus based on these findings. However, the accuracy of breast MRI for staging purposes is only tested in sporadic cancers.

METHODS

We assessed concordance of radiologic staging using MRI with histopathology in 49 tumors in 46 high risk patients (23 BRCA1, 12 BRCA2 and 11 Non-BRCA patients). The size of the total tumor area (TTA) was compared to pathology. In invasive carcinomas (n=45) the size of the largest focus (LF) was also addressed.

RESULTS

Correlation of MRI measurements with pathology was 0.862 for TTA and 0.793 for LF. TTA was underestimated in 8(16%), overestimated in 5(10%), and correctly measured in 36(73%) cases. LF was underestimated in 4(9%), overestimated in 5(11%), and correctly measured in 36(80%) cases. Impact of BRCA 1 or 2 mutations on the quality of size estimation was not observed.

CONCLUSIONS

Tumor size estimation using breast MRI in high risk patients is comparable to its performance in sporadic cancers. Therefore, breast MRI can safely be used for treatment planning.

The role of magnetic resonance imaging in early breast cancer

Despite recent evidence that fails to detect a benefit in surgical and local recurrence outcomes in those who receive optimal surgery and adjuvant systemic and radiotherapy, magnetic resonance imaging (MRI) is still being employed. We review the recent literature to clarify the role in the use of MRI in early breast cancer. A literature search using the Medline and Ovid databases was conducted between 2004 and 2011 using the terms "magnetic resonance imaging' and 'early breast cancer'. Only articles with clinical trials published in English in adult humans with available abstracts were included. Articles on high-risk women, response to neoadjuvant therapy, advanced breast cancer, the occult primary, the contralateral breast and technical articles were excluded. Articles examining the role of MRI in the staging of early breast cancer were retained. Over 260 articles regarding breast MRI have been published in the last 5 years. Additional foci may be found in 16% of patients but the impact on the extent of surgery and local recurrence rate is yet to be defined. Certain sub-groups who may benefit include those with invasive lobular carcinoma and mammographically dense breasts and those for consideration of partial breast irradiation. With standard adjuvant radiotherapy, there is no benefit in routine MRI with respect surgical extent and local recurrence. Should MRI be used, pre-operative biopsy to confirm additional disease must be undertaken prior to a change in surgical extent of resection. However, MRI may be useful in the evaluation of those who can be considered for partial breast irradiation. Centres undertaking breast MRI must have MRI-biopsy capabilities and constantly audit the reporting of MRI with correlation to the final pathology.

Preoperative breast magnetic resonance imaging: applications in clinical practice

Results of large randomized trials have shown that survival rates after breast conserving surgery are equivalent to those obtained by radical mastectomy. Breast conserving surgery with wide local excision in women with early stage breast cancer who are thought to have a single and resectable tumour as determined by clinical examination and conventional imaging followed by postoperative irradiation is the standard of care in early breast cancer. Mapping of local disease is the key element to guide optimal surgery to obtain tumour-free margins, thereby decreasing risk of local recurrence. The usual preoperative workup of breast malignancy consists of clinical breast examination and mammography with or without ultrasound. However, mammography and ultrasound fail to accurately assess tumour extent in as many as a third of patients eligible for breast conserving therapy. It is well established that magnetic resonance imaging is far superior to mammography (with and without ultrasound) for mapping the local extent of breast cancer. Experts advocate its use despite its high costs, high number of false positive findings, and lack of evidence from randomized prospective trials and, notably, fear of "overtreatment." This article discusses the current role of breast magnetic resonance imaging with its clinical advantages and applications.

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 science in the treatment of breast cancer when tumor multicentricity is present

During the past 100 years, there have been two major controversies with regard to the treatment of primary breast cancer. The first controversy, which occurred approximately 35 years ago, questioned the performance of radical mastectomy, as originally proposed by Halsted in the 1890s. That controversy was resolved by the use of laboratory and clinical research, hypothesis formulation, and evaluation of the efficacy of the latter through the conduct of randomized clinical trials. A second major controversy arose when magnetic resonance imaging began to detect the presence of tumor multicentricity in many breast cancer patients, resulting in a resurgence in mastectomy in women who could have been treated with breast-preserving surgery. Because the use of science resolved the first controversy, I investigated whether there was scientific evidence to justify the current reversion to mastectomy. Extensive examination of the vast amount of recent medical literature related to that subject, that is, individual articles, review articles, and reports from the use of clinical trials, demonstrated that many physicians are not familiar with the scientific method, and thus, were unable to present, in those articles, credible evidence to support mastectomy in the presence of tumor cell multicentricity. Aside from the randomized clinical trial conducted by the National Surgical Adjuvant Breast and Bowel Project begun in 1976, which demonstrated no statistically significant difference in disease-free survival, distant disease-free survival, and overall survival between mastectomy and lumpectomy with or without radiation therapy, there has been no information in any of the few recently conducted studies involving multicentricity to justify the current resurgence in mastectomy.

Multifocal, multicentric and contralateral breast cancers: breast MR imaging in the preoperative evaluation of patients with newly diagnosed breast cancer

PURPOSE

This study was done to verify the usefulness of preoperative breast magnetic resonance (MR) imaging in patients with newly diagnosed breast cancer.

MATERIALS AND METHODS

A retrospective analysis of 291 patients with invasive breast cancer newly diagnosed with conventional breast imaging (mammography and ultrasound) was performed. All patients underwent MR imaging prior to surgery. The MR imaging detection rate of additional malignant cancers occult to mammography and ultrasound was calculated. Data were analysed with Fisher's exact test (p<0.05) according to the following parameters: histopathological features of the index tumour (histological type and size) and mammographic density [according to the Breast Imaging Reporting and Data System (BI-RADS) classification from 1 fatty to 4 dense). The gold standard was the histological examination on the surgical specimen.

RESULTS

MR imaging identified 40 mammographically and sonographically occult malignant lesions other than the index cancer in 27/291 patients (9%). These additional cancers were located in the same quadrant as the index cancer in 13 women (4%), in a different quadrant in 12 (4%) and in the contralateral breast in the remaining two (1%). The cancer detection rate in the subgroup of index cancers with lobular histological type was 25%, significantly higher (p=0.03) than the detection rate of 11% recorded in the subgroup of ductal cancers. The cancer detection rate in the subgroup of index cancers >2 cm was 27%, significantly higher (p=0.001) than the rate of 8% found in the subgroup of index cancers <2 cm. Mammographic density was not correlated (p=0.48) with MR detection of additional cancer, with 14% of additional malignancies being detected in both dense and fatty breasts.

CONCLUSIONS

In patients with newly diagnosed invasive breast cancer, preoperative MR imaging is useful for detecting additional synchronous malignancies that are not detected on conventional breast imaging. The cancer detection rate is 9%. The use of preoperative MR imaging as an adjunct to conventional breast imaging in women with an infiltrating lobular index cancer and an index cancer >2 cm is especially beneficial.

Application of MR mammography beyond local staging: is there a potential to accurately assess axillary lymph nodes? evaluation of an extended protocol in an initial prospective study

OBJECTIVE

The purpose of our study was to clinically test an extended MR mammography (MRM) protocol for combined local staging (T-staging) and locoregional staging (N-staging) of breast cancer within one single examination using a dedicated whole-body scanner.

SUBJECTS AND METHODS

Fifty-six consecutive primary breast cancer patients without prior treatment underwent MRM and surgicopathological N-staging. The MRM protocol (10 minutes; axial T1-weighted gradient-recalled echo; dynamic contrast-enhanced; T2-weighted; turbo spin-echo) was extended to evaluate axillary lymph nodes (90 seconds; coronal T2-weighted HASTE; T1-weighted volumetric breath-hold examination; field of view, both axillae, supraclavicular nodes, and cervical nodes). A dedicated whole-body scanner was used. First, two experienced radiologists independently rated the presence of lymph node metastasis (present or absent, weighted kappa). Second, predefined descriptors were applied by both readers to differentiate lymph node status. These were statistically analyzed using univariate chi-square statistics, sensitivity and specificity, positive likelihood ratio, diagnostic odds ratio (OR), and multivariate statistics (binary logistic-regression, receiver operating characteristics, and chi-squared automatic interaction detection [CHAID] tree).

RESULTS

Most significant predictors (p < 0.001) of present metastasis were "irregular margin" (diagnostic OR, 14.0), "inhomogeneous cortex" (diagnostic OR, 8.4), "perifocal edema" (positive likelihood ratio, 100) and "asymmetry" (diagnostic OR, 19.5). CHAID tree identified "asymmetry" and "irregular margin" as significant predictors (adjusted-p < 0.05) for present metastasis (PPV: 100%), whereas absence of "asymmetry" and "homogeneous internal structure" were highly predictive of absent metastasis (negative predictive value, 94.3%). Combination of significant descriptors using binary logistic regression revealed an area under the receiver operating characteristic curve of 0.93 (p < 0.001). Interrater agreement was "almost-perfect" (κ = 0.95).

CONCLUSION

Combined T-staging and locoregional staging (N-staging) was possible within one imaging session using the proposed protocol. Despite a minimal increase in examination time, high diagnostic accuracy and excellent interrater reliability were achieved.

Effect of Magnetic Resonance Imaging on Breast Conservation Therapy versus Mastectomy: A Review of the Literature

The utilization of MRI in the workup of breast cancer has played a controversial role in the surgical treatment of this disease. With the higher resolution of breast tissue afforded, additional lesions are being identified that often warrant additional procedures, subsequently affecting the decision to proceed with breast conservation therapy versus mastectomy. In this paper, a literature review is presented to help illuminate some of the benefits and pitfalls of employing MRI as a diagnostic tool in the care of breast cancer, while additionally providing insight into the management alterations this imaging modality can engender. Though further research is required in a randomized prospective form to fully answer this question, evidence for and against its use continues to mount, especially for select patient groups.