Diagnostic Performance of Breast MRI in the Evaluation of Contralateral Breast in Patients with Diagnosed Breast Cancer

Aims: The purpose of our study was to evaluate the diagnostic performance of breast magnetic resonance imaging (MRI) in the evaluation of contralateral breast  in patients with diagnosed breast cancer. A secondary objective was to determine accuracy of breast MRI in diagnosing multi-focal and multicentric lesions in the ipsilateral breast. Materials and Methods: Using a non-probability convenience sampling technique, patients with histopathologically diagnosed breast cancer with MRI of breast performed to exclude additional lesions were included. MRI findings were correlated with histopathology. In addition, follow-up imaging with mammography and ultrasound was also assessed for establishing stability of negative findings and for the detected of benign lesions. Results: Out of 157 MRI breast conducted during the period of 2008 to 2013, 49 were performed for patients with diagnosed breast cancer. The sample comprised of all females with mean age 50.7±11.0 years. The patient follow-up imaging was available for a period of 2-5 years. The sensitivity, specificity, and positive and negative predictive values of MRI in the detection of multifocal/multicenteric lesions was 85.7%, 88.8%, 60% and 96.6% respectively and for the detection of lesions in the contralateral breast were 100%, 97%, 83.3% and 100% respectively. Conclusions: Our study highlights the diagnostic performance and the added value of MRI in the detection of multifocal /multicenteric and contralateral malignant lesions. In patients with diagnosed breast cancer having dense breast parenchyma and with infiltrating lobular carcinoma as the index lesion MRI is particularly useful with excellent negative predictive value in the exclusion of additional malignant foci in the ipsilateral and contralateral breasts.     

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.     

Added cancer yield of breast magnetic resonance imaging screening in women with a prior history of chest radiation therapy

BACKGROUND:

Recommendation for breast magnetic resonance imaging (MRI) screening for women with a prior history of chest radiation is currently based on expert opinion, because existing data are very scant. The objective of this study was to evaluate added cancer yield of screening breast MRI in this population.

METHODS:

A retrospective review identified 98 women with a prior history of chest radiation therapy who had screening mammography and screening MRI performed at the authors' institution between January 2004 and July 2010. Medical records of these patients and results of 558 screening studies (296 mammograms and 262 MRI) were reviewed. Sensitivity, specificity, positive predictive value, negative predictive value, and added cancer yield were calculated.

RESULTS:

Malignancy was diagnosed in 13 patients, invasive cancer was diagnosed in 10 patients, and ductal carcinomas in situ was diagnosed in 3 patients. The median latency from completion of radiation to detection of the breast cancer was 18 years (range, 8‐37 years). Of the 13 cancers, 12 (92%) were detected by MRI, and 9 (69%) by mammography. For mammography, the sensitivity, specificity, positive predictive value, and negative predictive value were 69%, 98%, 82%, and 95%, respectively; and, for MRI, these values were 92%, 94%, 71%, and 99%, respectively. In 4 of 98 patients, cancer was diagnosed on MRI only, resulting in an incremental cancer detection rate of 4.1% (95% confidence interval, 1.6%‐10%).

CONCLUSIONS:

The current results indicated that MRI is a useful adjunct modality for screening high‐risk women who have a prior history of chest radiation therapy, resulting in a 4.1% (4 of 98 women) added cancer detection rate. The authors concluded that both MRI and mammography should be used to screen women in this high‐risk group. Cancer 2013. © 2012 American Cancer Society.     

Breast MRI in clinically and mammographically occult breast cancer presenting with an axillary metastasis: A systematic review

Background

Axillary metastatic lymphadenopathy with no primary tumour identified in the breast on physical examination, mammography or ultrasound is referred to as occult breast cancer. The goal of this systematic review is to give an overview of the value and additional considerations of using breast MRI in occult breast cancer.

Methods

The databases of Pubmed, Embase, CINAHL and the Cochrane library were searched for studies addressing the use of breast MRI in occult breast cancer. Cross-referencing was used to find additional articles.

Results

8 retrospective studies were included. Breast MRI can detect an otherwise occult breast cancer in more than two thirds of patients with a high sensitivity but lower specificity. In 80% of patients MRI detected lesions could be localized again by using ultrasound. Furthermore the size and localization of the lesions found on MRI most often correlated closely with findings at pathology. Breast MRI also provided the possibility of breast conserving surgery in one thirds of patients.

Conclusion

Breast MRI can result in additional detection of otherwise occult lesions in occult breast cancer. Because of low specificity of malignant lesion detection by breast MRI, lesions should be histologically confirmed. This can be achieved either by MRI or ultrasound guided biopsy, as long as all MRI detected lesions are histologically checked. Routine application of breast MRI in occult breast cancer may also alter locoregional treatment by offering the possibility of breast conserving surgery in one thirds of patients.     

Low Rates of Additional Cancer Detection by Magnetic Resonance Imaging in Newly Diagnosed Breast Cancer Patients Who Undergo Preoperative Mammography and Ultrasonography

Purpose

We evaluated the efficacy of breast magnetic resonance imaging (MRI) for detecting additional malignancies in breast cancer patients newly diagnosed by breast ultrasonography and mammography.

Methods

We retrospectively reviewed the records of 1,038 breast cancer patients who underwent preoperative mammography, bilateral breast ultrasonography, and subsequent breast MRI between August 2007 and December 2010 at single institution in Korea. MRI-detected additional lesions were defined as those lesions detected by breast MRI that were previously undetected by mammography and ultrasonography and which would otherwise have not been identified.

Results

Among the 1,038 cases, 228 additional lesions (22.0%) and 30 additional malignancies (2.9%) were detected by breast MRI. Of these 228 lesions, 109 were suspected to be malignant (Breast Imaging-Reporting and Data System category 4 or 5) on breast MRI and second-look ultrasonography and 30 were pathologically confirmed to be malignant (13.2%). Of these 30 lesions, 21 were ipsilateral to the main lesion and nine were contralateral. Fourteen lesions were in situ carcinomas and 16 were invasive carcinomas. The positive predictive value of breast MRI was 27.5% (30/109). No clinicopathological factors were significantly associated with additional malignant foci.

Conclusion

Breast MRI was useful in detecting additional malignancy in a small number of patients who underwent ultrasonography and mammography.     

Clinical Outcome of Magnetic Resonance Imaging-Detected Additional Lesions in Breast Cancer Patients

Purpose

The aim of this study was to investigate the clinical outcome of additional breast lesions identified with breast magnetic resonance imaging (MRI) in breast cancer patients.

Methods

A total of 153 patients who underwent breast MRI between July 2006 and March 2008 were retrospectively reviewed. Thirty-three patients (21.6&) were recommended for second-look ultrasound (US) for further characterization of additional lesions detected on breast MRI and these patients constituted our study population.

Results

Assessment for lesions detected on breast MRI consisted of the following: 25 benign lesions (73.5&), two indeterminate (5.9%), and seven malignant (20.6%) in 33 patients. Second-look US identified 12 additional lesions in 34 lesions (35.3%) and these lesions were confirmed by histological examination. Of the 12 lesions found in the 11 patients, six (50.0%) including one contralateral breast cancer were malignant. The surgical plan was altered in 18.2% (six of 33) of the patients. The use of breast MRI justified a change in treatment for four patients (66.7%) and caused two patients (33.3&) to undergo unwarranted additional surgical procedures.

Conclusion

Breast MRI identified additional multifocal or contralateral cancer which was not detected initially on conventional imaging in breast cancer patients. Breast MRI has become an indispensable modality in conjunction with conventional modalities for preoperative evaluation of patients with operable breast cancer.     

乳腺癌3.0T MRI动态增强及扩散加权成像特点

目的 分析乳腺癌3.0 T MRI动态增强及扩散加权成像（DWI）的表现特征。方法 回顾性分析经病理检查证实的36例乳腺癌的3.0T MRI影像资料,分析其表现。结果 乳腺癌MRI表现：平扫T1WI病灶呈等或稍低信号;T2WI呈等或稍高信号;肿块形状不规则,部分呈深浅不同程度分叶状,边界模糊,并见毛刺征。DWI像：所有病灶均呈高信号,ADC图呈低信号ADC值为（0.97±0.22）×10^-3 mm²/s。动态增强示：不均匀强化,多呈斑点状、条片状或团状,部分病灶周围血管影增多;时间－信号强度曲线：流出型（Ⅲ型）曲线29例（80.6%）;平台型（Ⅱ型）型曲线5例（13.9%）; 流入型（Ⅰ型）曲线2例（5.5%）。36例中34例诊断为乳腺癌,2例误诊为纤维腺瘤,诊断符合率为94.4%。结论 乳腺癌具有一定MRI表现特征,结合3.0T MRI动态增强及DWI检查对乳腺癌的诊断具有较高的应用价值。     

MRI技术在乳腺癌诊断中的应用进展

乳腺癌作为女性恶性肿瘤的常见病，其发病率和发病人数表现出逐年递增趋势。伴随诊治技术及方案的改进，乳腺癌的诊治方式、疗效监督及预后评估等各方面都有了显著提升，从而也对乳腺癌临床早期诊断的检出率及分期的准确率有了较高的要求。医学影像技术尤其是 MRI检查在乳腺疾病诊治方面不断取得新突破和新应用，乳腺MRI检查技术的角色和作用显得越发重要。MRI基础及功能序列扫描等多种辅助检查，多角度、全方位提供病灶相关解剖、血流动力学、功能及代谢等信息。因而需要全方面熟悉MRI检查技术在乳腺癌诊治中的应用现状，才能使之合理高效的运用于临床诊断、术前分期、治疗方案选取及疗效评估等各方面。     

Bilateral breast MR imaging: is it superior to conventional methods for the detection of contralateral breast cancer?

Background Breast MR imaging has emerged as a highly sensitive modality for the imaging of breast tumors. However, there have been no reports concerning the usefulness of bilateral breast MRI to evaluate the contralateral breast in Japan. The purpose of this study was to examine the frequency of primary bilateral breast cancer, and to investigate the role of bilateral breast MRI in the detection of contralateral breast cancer. Methods A retrospective review was performed of 556 consecutive women who had undergone surgery for the primary breast cancer. MR imaging was performed on a 1.5-T system. Both the breasts were examined in the coronal plane on the first-, second-, and fourth-phase dynamic images, acquired at 30, 90 s, and 4.5 min, respectively. The affected single breast was sagittally examined on images obtained in the third phase at 3 min. Results Twenty-four (4.3%) patients had bilateral breast cancer, 14 (2.5%) had synchronous cancer and 10 patients (1.8%) had metachronous cancer. In the 14 cases with synchronous cancer, bilateral breast malignancy was suspected at the time of the initial diagnosis in 6 cases. The detection rate of 18 contralateral breast cancer cases by only MMG, only US, MMG and US, and MRI were 50% (9/18), 67% (12/18), 78% (14/18) and 100% (17/17), respectively. For 8 of these cases with a second synchronous cancer, the corresponding rates were 75, 88, 100 and 100%, respectively. For the 10 cases with a second metachronous cancer, the rates were 30, 50, 60 and 100%, respectively. Conclusion Bilateral breast MRI is a more sensitive for the detection of contralateral breast cancers compared with conventional imaging methods. In particular, bilateral MRI also allows detection of metachronous contralateral cancers at an earlier stage during the postoperative follow-up period.     

The need for MRI before breast-conserving surgery

MRI has gained acceptance as a highly sensitive imaging modality for the detection of breast disease, with a potential role for surgical staging of patients with newly diagnosed breast cancer. Published literature suggests that MRI can detect additional cancer in the ipsilateral and contralateral breasts, thus supporting the use of MRI as a tool for the staging of patients considered for breast conservation therapy. Although the potential to provide relevant information is present, current MRI limitations involve the lack of specificity to differentiate between malignant versus high-risk and benign disease. For a small percentage of patients to benefit from the impact of MRI on surgical management, a larger percentage would need to undergo unnecessary biopsy or more extensive surgery. Given these caveats and lack of prospective trials demonstrating evidence of efficacy, caution should be exercised when deciding to routinely integrate MRI into the preoperative staging process.     

Contrast-enhanced MR imaging of breast lesions and effect on treatment.

PURPOSE: To assess the value of local staging with preoperative magnetic resonance imaging (MRI) in patients with suspect breast lesions and the effect on therapeutic approach. MATERIALS AND METHODS: Two hundred and four consecutive women with suspect breast lesions on clinical examination (CE) and/or mammography (MX) and/or ultrasound (US) underwent preoperative contrast-enhanced MRI. Detection of multifocal, multicentric and bilateral breast cancer by all three imaging modalities was evaluated. Results of preoperative breast MRI were discussed with the treating surgeons. The type of therapeutic change after preoperative MRI was marked on a questionnaire (none, additional fine needle aspiration, core biopsy, open biopsy, wider excision, mastectomy) and considered 'necessary' or 'unnecessary' using final histopathological results as gold standard. RESULTS: In 170 patients, breast cancer was diagnosed. MRI detected 96% of multifocal disease and 95% of multicentric disease, whereas MX depicted 37 and 18%, and US 41 and 9% of them, respectively. All bilateral breast cancers were seen on MRI; both MX and US detected 56%. Findings of more extensive disease and unsuspected multiple breast cancer foci identified on MRI only, changed the therapeutic approach correctly in 30.6% of breast cancer patients. Nine unnecessary wider excisions and three unnecessary FNA/core biopsies were performed because MRI overestimated the number or size of malignant lesions. CONCLUSION: Preoperative breast MRI is an important adjunct to conventional imaging in the loco-regional staging of breast cancer and a useful tool in treatment planning.     

Imaging modalities for prostate cancer

Prostate cancer is the most frequently diagnosed malignancy in the Western male population and the associated socioeconomic impact on healthcare is of great concern. Since the early 1990s, MRI has evolved into an important diagnostic imaging modality for prostate cancer patients. In this review, the applications of diagnostic imaging modalities in prostate cancer, such as transrectal ultrasound, computed tomography and MRI are described. The clinical value of these techniques in prostate cancer detection, localization, characterization, staging and active surveillance are discussed.     

The application of breast MRI in staging and screening for breast cancer

Contrast-enhanced breast magnetic resonance imaging (MRI) is a relatively new but increasingly used modality for the detection of breast cancer. MRI has demonstrated utility in identifying additional tumor foci and extent of disease in patients with known breast cancer. This is especially useful with invasive lobular carcinoma, which is difficult to evaluate on mammography. MRI has been found to identify the primary tumor in 70% to 86% of cases of occult breast cancer. Contrast-enhanced breast MRI has shown some usefulness in the detection of residual cancer following surgery but is limited by postoperative changes. In patients who have undergone neoadjuvant chemotherapy, breast MRI is most accurate in those patients in whom there is little or no response to chemotherapy. The use of contrast-enhanced breast MRlfor breast cancer screening is controversial. It has only been used in afew small studies of high-risk patients. The limitations of breast MRI include uptake in benign lesions and normal tissue, sensitivity for ductal carcinoma in situ, cost, and availability. This paper will discuss the uses, benefits, and limitations of contrast-enhanced breast MRI in the staging and screening of breast cancer.     

Does pre-operative breast magnetic resonance imaging in addition to mammography and breast ultrasonography change the operative management of breast carcinoma?

Magnetic resonance imaging (MRI) has been used for the local staging of breast cancer, especially to determine the extent of multiple lesions and to identify occult malignancies. The aim of this study was to evaluate the effect of pre-operative MRI on the surgical treatment of breast cancer. Between January 2006 and May 2007, 535 newly diagnosed breast cancer patients who planned to undergo breast conserving surgery had clinical examinations, bilateral mammography, breast ultrasonography, and breast MRI. The radiologic findings and clinicopathologic data were reviewed retrospectively. Ninety-eight (18.3%) patients had additional lesions, shown as suspicious lesions on breast MRI, but not detected with conventional methods. Eighty-four (15.7%) of these patients had a change in surgical treatment plans based on the MRI results. Forty-seven (8.8%) of the 84 patients had additional malignancies; the other 37 patients (6.9%) had benign lesions. The positive predictive value for MRI-based surgery was 56.0% (47 of 84 patients). During the period of study, the use of pre-operative MRI was increased with time (OR 1.20; 95% CI 1.16–1.23; P < 0.001), but the mastectomy rate did not change significantly (OR 0.98; 95% CI 0.95–1.00; P = 0.059). Multiple factors were analyzed to identify the patients more likely to undergo appropriate and complete surgery based on the additional findings of the pre-operative MRI, but the results were not statistically significant. This research suggests that a pre-operative MRI can potentially lower the rate of incompletely excised malignancies by identifying additional occult cancer prior to surgery and does not lead to an increase in the mastectomy rate; however, because some benign lesions are indistinguishable from suspicious or malignant lesions, excessive surgical procedures are unnecessarily performed in a significant portion of patients. In the future, the criteria for the use of MRI in local staging of breast cancer should be established.     

Role of MRI (magnetic resonance imaging) versus conventional imaging for breast cancer presurgical staging in young women or with dense breast

Aims

The role of magnetic resonance imaging (MRI) in the local staging of breast cancer is currently uncertain. The purpose of this prospective study is to evaluate the accuracy of preoperative MRI compared to conventional imaging in detecting breast cancer and the effect of preoperative MRI on the surgical treatment in a subgroup of women with dense breasts, young age, invasive lobular cancer (ILC) or multiple lesions.

Methods

Between January 2006 and October 2007, 91 patients with newly diagnosed breast cancer underwent preoperative clinical breast examination, mammography, bilateral breast ultrasonography and high-resolution breast MRI. All patients had histologically verified breast cancer. The imaging techniques were compared using the final pathological report as gold standard.

Results

The sensitivity of MRI for the main lesion was 98.9%, while for multiple lesions sensitivity was 90.7% and specificity 85.4%. After preoperative MRI, 13 patients (14.3%) underwent additional fine needle/core biopsies, 9 of whom had specimen positive for cancer. Preoperative MRI changed the surgical plan in 26 patients: in 19.8% of the cases breast conservative surgery was converted to mastectomy and in 7.7% of the patients a wider excision was performed. At a mean follow-up of 48 months, 2 local recurrences occurred (local failure rate = 2.5%).

Conclusions

Enhanced sensitivity of breast MRI may change the surgical approach, by increasing mastectomy rate or suggesting the need of wider local excision. MRI can play an important role in preoperative planning if used in selected patients with high risk of multifocal/multicentric lesions. However, the histologic confirmation of all suspicious findings detected by MRI is mandatory prior to definite surgery.     

Multifocality and Multicentrality in Breast Cancer: Comparison of the Efficiency of Mammography,Contrast-Enhanced Spectral Mammography,and Magnetic Resonance Imaging in a Group of Patients with Primarily Operable Breast Cancer

Background: The multifocality and multicentrality of breast cancer (MFMCC) are the significant aspects that determine a specialist’s choice between applying breast-conserving therapy (BCT) or performing a mastectomy. This study aimed to assess the usefulness of mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in women diagnosed with breast cancer before qualifying for surgical intervention to visualize other (additional) cancer foci. Methods: The study included 60 breast cancer cases out of 630 patients initially who underwent surgery due to breast cancer from January 2015 to April 2019. MG, CESM, and MRI were compared with each other in terms of the presence of MFMCC and assessed for compliance with the postoperative histopathological examination (HP). Results: Histopathological examination confirmed the presence of MFMCC in 33/60 (55%) patients. The sensitivity of MG in detecting MFMCC was 50%, and its specificity was 95.83%. For CESM, the sensitivity was 85.29%, and the specificity was 96.15%. For MRI, all the above-mentioned parameters were higher as follows: sensitivity—91.18%; specificity—92.31%. Conclusions: In patients with MFMCC, both CESM and MRI are highly sensitive in the detection of additional cancer foci. Both CESM and MRI change the extent of surgical intervention in every fourth patient.     

Magnetic resonance imaging in breast cancer recurrence

Purpose. To determine the sensitivity, specificity and accuracy of magnetic resonance imaging (MRI) in detecting breast cancer recurrence. Materials and methods. Forty women conservatively treated for breast cancer underwent MRI and confirmation on histology and cytology of suspected local recurrence. In these patients both clinical and mammographic/ultrasound features of local recurrence were nonspecific or suspicious. All patients were examined at least 1 year after completion of radiation treatment. Dynamic magnetic resonance imaging was performed with a 1.5 T unit using a dedicated bilateral breast coil. Qualitative and quantitative data were obtained. Statistical analysis was also performed with the Student T-test. Results. Breast cancer recurrence was confirmed on histology in 22 patients. MRI identified all the 22 breast recurrent cancers. False-positive contrast enhancement was seen in only two patients. In four patients recurrence was classified as multifocal. In one patient the tumor was detected in the contralateral breast. MRI showed 95% accuracy, 100% sensitivity, 88.8% specificity with 5% false-positives and 100% negative predictive value. Conclusion. Dynamic MRI appears a valuable technique for differentiation of post-treatment changes from recurrent carcinoma and for guiding the histological confirmation. Its high negative predictive value may have an impact on follow-up of treated breast.     

New technologies in screening for breast cancer: a systematic review of their accuracy

We systematically reviewed the literature on the accuracy of new technologies proposed for breast cancer screening. Four potential tests were identified (ultrasound, magnetic resonance imaging (MRI), full-field digital mammography (FFDM), and computer-aided detection (CAD)) for which primary studies met quality and applicability criteria and provided adequate data on test accuracy. These technologies have been assessed in cross-sectional studies of test accuracy where the new test is compared to mammography. Ultrasound, used as an adjunct to mammography in women with radiologically dense breasts, detects additional cancers and causes additional false positives. Magnetic resonance imaging may have a better sensitivity (but lower specificity) than mammography in selected high-risk women, but studies of this technology included small number of cancers. Computer-aided detection may enhance the sensitivity of mammography and warrants further evaluation in large prospective trials. One study of FFDM suggests that it may identify some cancers not identified on conventional mammography and may result in a lower recall rate. The evidence is currently insufficient to support the use of any of these new technologies in population screening, but would support further evaluation.     

Development and Implementation of an Algorithm to Guide MRI Screening in Patients With a Personal History of Treated Breast Cancer

IntroductionLimited data exist to guide appropriate use of magnetic resonance imaging (MRI) screening in women with a personal history of breast cancer. We developed an algorithm to inform the use of MRI screening in patients with a personal history, implemented it, and evaluated initial implementation at our community and academic practice sites.Patients and MethodsA multidisciplinary committee of providers developed the initial algorithm on the basis of available literature and consensus. To evaluate projected MRI utilization based on the initial algorithm and inform algorithm revision, charts of patients < 80 years of age diagnosed and treated in 2010 with stage 0-III breast cancer (n = 236) were reviewed. The revised algorithm was implemented into the electronic medical record (September 2013). Thirteen months after implementation (2014-2015), chart review of patients with a personal history of breast cancer who underwent screening MRI was performed to assess algorithm adherence.ResultsBefore algorithm development, 9% (20/236) of patients received MRI screening (6 genetic mutation/family history, 4 occult primary, 8 young age/breast density, 2 unknown). Use of MRI screening was projected to increase to 25% with algorithm implementation. In postimplementation review, we identified 183 patients with a personal history of breast cancer who underwent screening MRI, with 94% algorithm adherence.ConclusionWe successfully developed and implemented an algorithm to guide MRI screening in patients with a personal breast cancer history. Clinicians can use this algorithm to guide patient discussions regarding the utility of MRI screening. Further prospective study, including cancer detection rates, biopsy rate, and mortality, are necessary to confirm the algorithm’s usefulness.     

Review of Preoperative Magnetic Resonance Imaging (MRI) in Breast Cancer: Should MRI Be Performed on All Women with Newly Diagnosed,Early Stage Breast Cancer?

Randomized controlled trials have shown equivalent survival for women with early stage breast cancer who are treated with breast‐conservation therapy (local excision and radiotherapy) or mastectomy. Decades of experience have demonstrated that breast‐conservation therapy provides excellent local control based on defined standards of care. Magnetic resonance imaging (MRI) has been introduced in preoperative staging of the affected breast in women with newly diagnosed breast cancer because it detects additional foci of cancer that are occult on conventional imaging. The median incremental (additional) detection for MRI has been estimated as 16% in meta‐analysis. In the absence of consensus on the role of preoperative MRI, we review data on its detection capability and its impact on treatment. We outline that the assumptions behind the adoption of MRI, namely that it will improve surgical planning and will lead to a reduction in re‐excision surgery and in local recurrences, have not been substantiated by trials. Evidence consistently shows that MRI changes surgical management, usually from breast conservation to more radical surgery; however, there is no evidence that it improves surgical care or prognosis. Emerging data indicate that MRI does not reduce re‐excision rates and that it causes false positives in terms of detection and unnecessary surgery; overall there is little high‐quality evidence at present to support the routine use of preoperative MRI. Randomized controlled trials are needed to establish the clinical, psychosocial, and long‐term effects of MRI and to show a related change in treatment from standard care in women newly affected by breast cancer. CA Cancer J Clin 2009;59:290–302. © 2009 American Cancer Society, Inc.