Isabelle Trop

Sentinel Node Biopsy After Neoadjuvant Chemotherapy in Biopsy-Proven Node-Positive Breast Cancer: The SN FNAC Study

PURPOSE An increasing proportion of patients (> 30%) with node-positive breast cancer will obtain an axillary pathologic complete response after neoadjuvant chemotherapy (NAC). If sentinel node (SN) biopsy (SNB) is accurate in this setting, completion node dissection (CND) morbidity could be avoided. PATIENTS AND METHODS In the prospective multicentric SN FNAC study, patients with biopsy-proven node-positive breast cancer (T0-3, N1-2) underwent both SNB and CND. Immunohistochemistry (IHC) use was mandatory, and SN metastases of any size, including isolated tumor cells (ypN0[i+], ≤ 0.2 mm), were considered positive. The optimal SNB identification rate (IR) ≥ 90% and false-negative rate (FNR) ≤ 10% were predetermined. RESULTS From March 2009 to December 2012, 153 patients were accrued to the study. The SNB IR was 87.6% (127 of 145; 95% CI, 82.2% to 93.0%), and the FNR was 8.4% (seven of 83; 95% CI, 2.4% to 14.4%). If SN ypN0(i+)s had been considered negative, the FNR would have increased to 13.3% (11 of 83; 95% CI, 6.0% to 20.6%). There was no correlation between size of SN metastases and rate of positive non-SNs. Using this method, 30.3% of patients could potentially avoid CND. CONCLUSION In biopsy-proven node-positive breast cancer after NAC, a low SNB FNR (8.4%) can be achieved with mandatory use of IHC. SN metastases of any size should be considered positive. The SNB IR was 87.6%, and in the presence of a technical failure, axillary node dissection should be performed. We recommend that SN evaluation with IHC be further evaluated before being included in future guidelines on the use of SNB after NAC in this setting.

Quality Initiatives: Guidelines for Use of Medical Imaging during Pregnancy and Lactation

The use of computed tomography (CT) and magnetic resonance (MR) imaging has increased tremendously in the past 2 decades. Hence, pregnant and breast-feeding women, although generally healthier than the population at large, are also more likely to require contrast material-enhanced imaging. When a contrast-enhanced CT or MR imaging study is being considered for a pregnant or lactating patient, the potential risks to the fetus related to exposure to radiation, high magnetic fields, or contrast agents must be considered and weighed carefully against the risks of potential misdiagnosis due to withholding contrast agents and imaging studies. Fetal radiation doses up to 1 mGy are considered acceptable; with larger doses, the risk of carcinogenesis approximately doubles, although it remains low in absolute terms. No damage to a developing human fetus caused by MR imaging exposure has been documented. However, caution is advised, and risks and benefits must always be considered before evaluating a pregnant patient with MR imaging. The use of iodinated contrast agents is generally safe during pregnancy; nevertheless, these agents should be used with caution due to the risk of fetal hypothyroidism and should be administered only when the clinical situation clearly requires doing so. The use of gadolinium-based contrast agents during pregnancy remains controversial due to lack of human clinical data and potential toxicity. Use of all contrast agents is considered safe during lactation. It is hoped that this knowledge will help radiologists develop a consensus with their clinical colleagues regarding case management of pregnant and lactating patients.

Breast abscesses: evidence-based algorithms for diagnosis, management, and follow-up.

Radiologists who regularly perform breast ultrasonography will likely encounter patients with breast abscesses. Although the traditional approach of surgical incision and drainage is no longer the recommended treatment, there are no clear guidelines for management of this clinical condition. Breast abscesses that develop in the puerperal period generally have a better course than nonpuerperal abscesses, which tend to be associated with longer treatment times and a higher rate of recurrence. The available literature on treatment of breast abscesses is imperfect, with no clear consensus on drainage, antibiotic therapy, and follow-up. By synthesizing the data available from studies published in the past 20 years, an evidence-based algorithm for management of breast abscesses has been developed. The proposed algorithm is easy to follow and has been validated by a multidisciplinary team approach and applied successfully during the past 2 years. Breast abscesses are a challenging clinical condition, and radiologists have a pivotal role in evaluation and follow-up of these lesions.

Nonmasslike Enhancement at Breast MR Imaging: The Added Value of Mammography and US for Lesion Categorization

PURPOSE To determine the value of adding conventional imaging (mammography and ultrasonography [US]) to nonmasslike enhancement (NMLE) analysis with breast magnetic resonance (MR) imaging for predicting malignancy and for building an interpretation model incorporating all imaging modalities. MATERIALS AND METHODS The institutional ethics committees approved the study and granted a waiver of informed consent. In 115 women (mean age, 48.3 years; range, 21-76 years; 56 malignant, 12 high-risk, and 63 benign lesions), 131 NMLE lesions were analyzed. Two independent readers first classified MR images by using descriptive Breast Imaging Reporting and Data System (BI-RADS) criteria (BI-RADS classification with MR images alone [BI-RADS(MR)]) and later repeated this classification, adding information from conventional imaging (BI-RADS classification with combination of MR images and conventional images [BI-RADS(MR+Con)]). Lesion diagnosis was established with surgical histopathologic findings (n = 68), percutaneous biopsy results (n = 25), or 2 years of stability at MR imaging (n = 38). Receiver operating characteristic curves were built to compare BI-RADS(MR) with BI-RADS(MR+Con). A multivariate interpretation model was constructed and validated in a distinct cohort of 44 women. RESULTS Values for inter- and intraobserver agreement, respectively, were better for BI-RADS(MR+Con) (κ = 0.847 and 0.937) than for BI-RADS(MR) (κ = 0.748 and 0.861). For both readers, the areas under the receiver operating characteristic curve (AUCs) for diagnosis of malignancy were also superior when BI-RADS(MR+Con) (AUC = 0.91 [reader 1] and 0.93 [reader 2]) was compared with BI-RADS(MR) (AUC = 0.84 [reader 1] and 0.87 [reader 2]) (P < .05). An interpretation model combining conventional imaging with MR imaging criteria showed very good discrimination (AUC = 0.89 [training set] and 0.90 [validating set]). CONCLUSION Adding conventional imaging to NMLE lesion characterization at breast MR imaging improved the diagnostic performance of radiologists, and the interpretation model used offers good accuracy with the potential to optimize the reproducibility of NMLE analysis at MR imaging.

Normal fetal anatomy as visualized with fast magnetic resonance imaging.

The development of ultrafast sequences has revolutionized fetal magnetic imaging (MRI). Fetal anatomy can be characterize precisely by MRI. This is particularly true for evaluation of the central nervous system, for which magnetic resonance (MR) evaluation is superior to ultrasound evaluation. MR allows analysis of development of the cerebrum as well as posterior fossa structures. Awareness of the normal sequence of maturation as well as the approximate timing of development of key structures is useful for evaluating the developing fetus. MRI also permits evaluation of the oropharynx, lungs, diaphragm, and intra-abdominal and retroperitoneal structures. Occasionally, beautiful depiction of smaller structures, including extremities and details of the face and neck may be obtained, but this is dependent on the orientation of the fetus and the plane of imaging as well as the section thickness. MRI is useful in assignment of fetal gender as well as in evaluation of the chorionicity of twin gestations. This report illustrates the normal appearance of the developing fetus as seen on fast sequences during the second and third trimesters.

Magnetic Resonance Imaging Improves Breast Screening Sensitivity in BRCA Mutation Carriers Age ≥ 50 Years: Evidence From an Individual Patient Data Meta-Analysis

PURPOSE There is no consensus on whether magnetic resonance imaging (MRI) should be included in breast screening protocols for women with BRCA1/2 mutations age ≥ 50 years. Therefore, we investigated the evidence on age-related screening accuracy in women with BRCA1/2 mutations using individual patient data (IPD) meta-analysis. PATIENTS AND METHODS IPD were pooled from six high-risk screening trials including women with BRCA1/2 mutations who had completed at least one screening round with both MRI and mammography. A generalized linear mixed model with repeated measurements and a random effect of studies estimated sensitivity and specificity of MRI, mammography, and the combination in all women and specifically in those age ≥ 50 years. RESULTS Pooled analysis showed that in women age ≥ 50 years, screening sensitivity was not different from that in women age < 50 years, whereas screening specificity was. In women age ≥ 50 years, combining MRI and mammography significantly increased screening sensitivity compared with mammography alone (94.1%; 95% CI, 77.7% to 98.7% v 38.1%; 95% CI, 22.4% to 56.7%; P < .001). The combination was not significantly more sensitive than MRI alone (94.1%; 95% CI, 77.7% to 98.7% v 84.4%; 95% CI, 61.8% to 94.8%; P = .28). Combining MRI and mammography in women age ≥ 50 years resulted in sensitivity similar to that in women age < 50 years (94.1%; 95% CI, 77.7% to 98.7% v 93.2%; 95% CI, 79.3% to 98%; P = .79). CONCLUSION Addition of MRI to mammography for screening BRCA1/2 mutation carriers age ≥ 50 years improves screening sensitivity by a magnitude similar to that observed in younger women. Limiting screening MRI in BRCA1/2 carriers age ≥ 50 years should be reconsidered.

Chronic granulomatous mastitis: Imaging, pathology and management

PURPOSE The aim of this study is to describe the clinical and radiological presentation of chronic granulomatous mastitis. MATERIAL AND METHODS We retrospectively reviewed the clinical and radiological data of 11 women with histologically proven chronic granulomatous mastitis (CGM) diagnosed between March 2008 and September 2011. RESULTS The diagnosis of CGM is often a challenging one that can mimic infectious and malignant breast conditions. Clinically, CGM most commonly presents as a mass, occasionally with associated erythema. The most frequent mammographic presentation is an asymmetric density, while ultrasound most commonly reveals a hypoechoic mass with tubular extensions and a striated echotexture. On MRI, the most specific finding is peripherally enhancing fluid or solid masses with fistulous tract to the skin, although the latter is not commonly encountered. Diagnosis can be reliably obtained by needle core or vacuum-assisted biopsy, and is established pathologically by the identification of granulomatous inflammation without caseous necrosis. CGM is a diagnosis of exclusion after infectious and foreign body causes are ruled out. Treatment options include oral steroids or surgery; both options are associated with similar recurrence rates. The disease tends to burn itself out and the option of conservative management with observation is a valid one. CONCLUSION CGM is a rare benign disease with no specific features clinically or at imaging. There are no radiologic findings that are specific of CGM, but in the appropriate clinical setting, the diagnosis can be suggested by the radiologist.

A plea for the biopsy marker: how, why and why not clipping after breast biopsy?

In the last decade, percutaneous breast biopsies have become a standard for the management of breast diseases. Biopsy clips allow for precise lesion localization, thus minimizing the volume of breast to be resected at the time of surgery. With the development of many imaging techniques (including mammography, sonography, and breast magnetic resonance imaging), one of the challenges of the multidisciplinary became to synthesize all informations obtained from the various imaging procedures. The use of biopsy markers after percutaneous biopsy is one of the keys for optimal patient management, helping the radiologist to deal with multiple lesions, to insure correlation across different imaging modalities and to follow-up benign lesions, helping the oncologist by marking a tumor prior to neoadjuvant chemotherapy, helping the surgeon by facilitating preoperative needle localization, to precisely mark the margins of extensive disease and to guide intraoperative tumor resection, and helping the pathologist to insure the lesion of interest has been removed and to identify the region of interest in a mastectomy specimen. We believe biopsy clip markers should be deployed after all percutaneous interventions and present in this review the arguments to support this statement. Minimal indications for clip deployment will also be detailed.

Localization of the surgical bed using supine magnetic resonance and computed tomography scan fusion for planification of breast interstitial brachytherapy

PURPOSE To evaluate the feasibility of supine breast magnetic resonance imaging (MR) for definition and localization of the surgical bed (SB) after breast conservative surgery. To assess the inter-observer variability of surgical bed delineation on computed tomography (CT) and supine MR. MATERIALS AND METHODS Patients candidate for breast brachytherapy and no contra-indications for MR were eligible for this study. Patients were placed in supine position, with the ipsilateral arm above the head in an immobilization device. All patients underwent CT and MR in the same implant/treatment position. Four points were predefined for CT-MRI image fusion. The surgical cavity was drawn on CT then MRI, by three independent observers. Fusion and analysis of CT and MR images were performed using the ECLIPSE treatment planning software. RESULTS From September 2005 to November 2008, 70 patients were included in this prospective study. For each patient, we were able to acquire axial T1 and T2 images of good quality. Using the predefined fusion points, the median error following the fusion was 2.7 mm. For each observer, volumes obtained on MR were, respectively, 30%, 38% and 40% smaller than those derived from CT images. A highly significant inter-observer variability in the delineation of the SB on CT was demonstrated (p<0.0001). On the contrary, all three observers agreed on the volume of the SB drawn on MR. CONCLUSION Supine breast MRI yields a more precise definition of the SB with a smaller inter-observer variability than CT and may obviate the need for surgical clips. The volume of the SB is smaller with MRI. In our opinion, CT-MRI fusion should be used for SB delineation, in view of partial breast irradiation.

Molecular classification of infiltrating breast cancer: toward personalized therapy.

Breast cancer is a heterogeneous disease, which comprises several molecular and genetic subtypes, each with characteristic clinicobiologic behavior and imaging patterns. Traditional classification of breast cancer is based on the histopathologic features but offers limited prognostic value. Novel molecular characterization of breast cancer with cellular markers has allowed a new classification that offers prognostic value, with predictive categories of disease aggressiveness. These molecular signatures also open the door to personalized therapeutic options, with new receptor-targeted therapies. For example, invasive cancer subtypes such as the luminal A and B subtypes show better prognosis and response to hormone receptor-targeted therapies compared with the triple-negative subtypes; on the other hand, triple-negative tumors respond better than luminal tumors to chemotherapy. Tumors that display amplification of the oncogene ERBB2 (also known as the HER2/neu oncogene) respond to drugs directed against this oncogene, such as trastuzumab. The imaging aspects of tumors correlate with molecular subgroups, as well as other pathologic features such as nuclear grade. Smooth tumor margins at mammography may be suggestive of a triple-negative breast cancer, and a human epidermal growth factor receptor 2 (HER2)-positive tumor is characteristically a spiculated mass with calcifications. Low-grade ductal carcinoma in situ (DCIS) is better detected with mammography, although magnetic resonance (MR) imaging may allow better characterization of high-grade DCIS. MR imaging diffusion sequences show higher values for the apparent diffusion coefficient for triple-negative and HER2-positive subtypes, compared with luminal A and B tumors. MR imaging is also a useful tool in the prediction of tumor response after chemotherapy, especially for triple-negative and HER2-positive subtypes.