Breast cancer staging with contrast-enhanced imaging. The benefits and drawbacks of MRI, CEM, and dedicated breast CT

Pretherapeutic breast cancer staging is pivotal for patient-centered disease management, guiding treatment stratification and assessing prognostic outcomes. Breast imaging plays a key role in both anatomic and prognostic staging by providing comprehensive insights into disease extent, localization, and tumor aggressiveness characteristics. To date, clinical image-based staging relies on conventional modalities such as digital mammography (DM), digital breast tomosynthesis (DBT), and ultrasound. Considering the phenotypic disparities of breast cancer and their relation to treatment response, other imaging techniques based on contrast-enhanced mechanisms, which highlight areas of increased neovascularity, appear indispensable in breast cancer staging. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) offers a comprehensive 3-dimensional assessment of extent of disease and characterization of lesions, capturing both morphological and functional aspects which are crucial for treatment and monitoring of the disease. Based on this established approach, contrast-enhanced x-ray-based techniques, with high spatial resolution, such as contrast-enhanced mammography (CEM) and dedicated contrast-enhanced breast computed tomography (dCEBCT), have emerged. This review outlines the current status, limitations, and ongoing challenges associated with each one contrast-enhanced imaging modality, while emphasis is given to key breast cancer manifestations and the optimal interpretation of their imaging phenotypes, in the current era of image-based (anatomic and prognostic) breast cancer staging.

Anatomical Approach for the Evaluation of the Nipple-Areolar Complex

The nipple-areolar complex (NAC) is an anatomically unique region from which several normal variants and pathologies arise. Understanding its anatomy is crucial for accurate clinical and imaging assessments, aiding with differential diagnosis, and ensuring radiologic-pathologic concordance. Mammography and US are commonly used for NAC evaluation; however, these are susceptible to technical limitations such as tissue superimposition and artifacts, compromising visualization of abnormalities in this area. Although MRI offers higher sensitivity, it is not the initial evaluation modality. A comprehensive clinical inspection is necessary because it may reveal abnormalities not apparent on imaging. This article offers an anatomical approach to the NAC evaluation, simplifying differential diagnoses by reviewing imaging techniques and clinical features of common NAC abnormalities.

Safety of Atypical Ductal Hyperplasia at the Nipple Margin in Nipple-Sparing Mastectomy

PURPOSE

Controversies persist regarding contraindications for nipple-sparing mastectomy (NSM). This study aimed to assess the accuracy of subareolar frozen section analysis and identify risk factors for nipple-areola complex (NAC) recurrence post NSM.

METHODS

Consecutive cases of primary invasive breast cancer undergoing NSM at our single center from January 2015 to December 2020 were retrospectively reviewed.

RESULTS

The nipples were retained in 126 patients (127 breasts), and the areola was retained with nipple excision for five breasts. Frozen section analysis demonstrated a sensitivity of 81.8% and specificity of 95.3%. The NAC recurrence rate was 4.3% over a median follow-up period of 48 (30-105) months. An atypical ductal hyperplasia (ADH) at the margin emerged as an independent factor for NAC recurrence in multivariate Cox regression analysis (hazard ratio, 25.464; 95% confidence interval, 1.841-352.145; p = 0.016). Kaplan-Meier survival analysis revealed no statistically significant reduction in overall survival rates (log-rank test, p = 0.660).

CONCLUSION

Frozen sections of subareolar tissue are reliable and re-excision may be necessary when ADH is detected at the nipple margin in NSM. The NAC recurrence rate was low, and the outcome was favorable following wide local excision.

Multimodality Imaging of Benign and Malignant Diseases of the Nipple-Areolar Complex

The nipple-areolar complex (NAC), a unique anatomic structure of the breast, encompasses the terminal intramammary ducts and skin appendages. Several benign and malignant diseases can arise within the NAC. As several conditions have overlapping symptoms and imaging findings, understanding the distinctive nipple anatomy, as well as the clinical and imaging features of each NAC disease process, is essential. A multimodality imaging approach is optimal in the presence or absence of clinical symptoms. The authors review the ductal anatomy and anomalies, including congenital abnormalities and nipple retraction. They then discuss the causes of nipple discharge and highlight best practices for the imaging workup of pathologic nipple discharge, a common condition that can pose a diagnostic challenge and may be the presenting symptom of breast cancer. The imaging modalities used to evaluate and differentiate benign conditions (eg, dermatologic conditions, epidermal inclusion cyst, mammary ductal ectasia, periductal mastitis, and nonpuerperal abscess), benign tumors (eg, papilloma, nipple adenoma, and syringomatous tumor of the nipple), and malignant conditions (eg, breast cancer and Paget disease of the breast) are reviewed. Breast MRI is the current preferred imaging modality used to evaluate for NAC involvement by breast cancer and select suitable candidates for nipple-sparing mastectomy. Different biopsy techniques (US -guided biopsy and stereotactic biopsy) for sampling NAC masses and calcifications are described. This multimodality imaging approach ensures an accurate diagnosis, enabling optimal clinical management and patient outcomes. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

A Nomogram Based on Conventional and Contrast-Enhanced Ultrasound for Pre-operative Prediction of Nipple-Areola Complex Involvement in Breast Cancer: A Prospective Study

OBJECTIVE

Accurately predicting nipple-areola complex (NAC) involvement in breast cancer is essential for identifying eligible patients for a nipple-sparing mastectomy. This study was aimed at developing a pre-operative nomogram for NAC involvement in breast cancer using conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS).

METHODS

All patients with primary breast cancer confirmed by pre-operative biopsy underwent US and CEUS examinations. Post-operative pathology was used as the gold standard in assessing NAC involvement. Lasso regression was used to select the predictors most associated with NAC involvement. A nomogram was constructed to calculate the diagnostic efficacy. The data were internally verified with 500 bootstrapped replications, and a calibration curve was generated to validate the predictive capability.

RESULTS

Seventy-six patients with primary breast cancer were included in this study, which included 16 patients (21.1%) with NAC involvement and 60 patients (78.9%) without NAC involvement. Among the 23 features of US and CEUS, Lasso regression selected one US feature and two CEUS features, namely, ductal echo extending from the lesion, ductal enhancement extending to the nipple and focal nipple enhancement. A nomogram was constructed, and the results revealed that the area under the curve, sensitivity, specificity and accuracy were 0.891, 81.3%, 86.7% and 85.5%, respectively. The calibration curve exhibited good consistency between the predicted probability and the actual probability.

CONCLUSION

The nomogram developed based on US and CEUS had good performance in predicting NAC involvement in breast cancer before surgery, which may facilitate the selection of suitable patients for NAC preservation with greater oncological safety.

Diagnostic Accuracy of Magnetic Resonance Imaging Features and Tumor-to-Nipple Distance for the Nipple-Areolar Complex Involvement of Breast Cancer: A Systematic Review and Meta-Analysis

OBJECTIVE

This systematic review and meta-analysis evaluated the accuracy of preoperative breast magnetic resonance imaging (MRI) features and tumor-to-nipple distance (TND) for diagnosing occult nipple-areolar complex (NAC) involvement in breast cancer.

MATERIALS AND METHODS

The MEDLINE, Embase, and Cochrane databases were searched for articles published until March 20, 2022, excluding studies of patients with clinically evident NAC involvement or those treated with neoadjuvant chemotherapy. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Two reviewers independently evaluated studies that reported the diagnostic performance of MRI imaging features such as continuity to the NAC, unilateral NAC enhancement, non-mass enhancement (NME) type, mass size (> 20 mm), and TND. Summary estimates of the sensitivity and specificity curves and the summary receiver operating characteristic (SROC) curve of the MRI features for NAC involvement were calculated using random-effects models. We also calculated the TND cutoffs required to achieve predetermined specificity values.

RESULTS

Fifteen studies (n = 4002 breast lesions) were analyzed. The pooled sensitivity and specificity (with 95% confidence intervals) for NAC involvement diagnosis were 71% (58-81) and 94% (91-96), respectively, for continuity to the NAC; 58% (45-70) and 97% (95-99), respectively, for unilateral NAC enhancement; 55% (46-64) and 83% (75-88), respectively, for NME type; and 88% (68-96) and 58% (40-75), respectively, for mass size (> 20 mm). TND had an area under the SROC curve of 0.799 for NAC involvement. A TND of 11.5 mm achieved a predetermined specificity of 85% with a sensitivity of 64%, and a TND of 12.3 mm yielded a predetermined specificity of 83% with a sensitivity of 65%.

CONCLUSION

Continuity to the NAC and unilateral NAC enhancement may help predict occult NAC involvement in breast cancer. To achieve the desired diagnostic performance with TND, a suitable cutoff value should be considered.

Preoperative Breast Magnetic Resonance Imaging: An Ontario Health (Cancer Care Ontario) Clinical Practice Guideline

BACKGROUND

The use of preoperative breast magnetic resonance imaging (MRI) after the diagnosis of breast cancer by mammography and/or ultrasound is inconsistent.

METHODS

After conducting a systematic review and meta-analysis comparing preoperative breast MRI versus no MRI, we reconvened to prepare a clinical practice guideline on this topic.

RESULTS

Based on the evidence that MRI improved recurrence, decreased the rates of reoperations (re-excisions or conversion mastectomy), and increased detection of synchronous contralateral breast cancer, we recommend that preoperative breast MRI should be considered on a case-by-case basis in patients diagnosed with breast cancer for whom additional information about disease extent could influence treatment. Based on stronger evidence, preoperative breast MRI is recommended in patients diagnosed with invasive lobular carcinoma for whom additional information about disease extent could influence treatment. For both recommendations, the decision to proceed with MRI would be conditional on shared decision-making between care providers and the patient, taking into account the benefits and risks of MRI as well as patient preferences. Based on the opinion of the Working Group, preoperative breast MRI is also recommended in the following more specific situations: (a) to aid in surgical planning of breast conserving surgery in patients with suspected or known multicentric or multifocal disease; (b) to identify additional lesions in patients with dense breasts; (c) to determine the presence of pectoralis major muscle/chest wall invasion in patients with posteriorly located tumours or when invasion of the pectoralis major muscle or chest wall is suspected; (d) to aid in surgical planning for skin/nipple-sparing mastectomies, autologous reconstruction, oncoplastic surgery, and breast conserving surgery with suspected nipple/areolar involvement; and (e) in patients with familial/hereditary breast cancer but who have not had recent breast MRI as part of screening or diagnosis.

Nipple-sparing Mastectomy: What the Radiologist Should Know

Nipple-sparing mastectomy (NSM) is increasingly offered to patients undergoing treatment of breast cancer and prophylaxis treatment for reduction of breast cancer risk. NSM is considered oncologically safe for appropriately selected patients and is associated with improved cosmetic outcomes and quality of life. Accepted indications for NSM have expanded in recent years, and currently only inflammatory breast cancer or malignancy involving the nipple is considered an absolute contraindication. Neoplasms close to and involving the nipple areolar complex are common, and cancer of the lactiferous ducts can spread to the nipple. Therefore, accurate determination of nipple involvement at imaging examinations is critical to identifying appropriate candidates for NSM and preventing local recurrence. Multiple imaging features have been described as predictors of nipple involvement, with tumor to nipple distance, enhancement between the index malignancy and the nipple, and nipple retraction demonstrating the highest predictive values. These features can be assessed at multimodality breast imaging, particularly at breast MRI, which demonstrates high specificity and negative predictive value for determining nipple involvement in malignancy. Online supplemental material is available for this article. ^©RSNA, 2022.

Prediction of nipple-areolar complex involvement by breast cancer: role of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)

Background

Skin-sparing and nipple-sparing mastectomies were considered as alternative techniques for modified radical mastectomy. In patients who are candidates for nipple-sparing mastectomy, preoperative assessment of the nipple-areolar complex (NAC) is essential for adequate surgical planning. Breast MRI is highly sensitive for cancer detection and has an important role in disease staging. The aim of this study was to estimate the role of DCE-MRI in predicting malignant NAC invasion by underlying breast cancer and assess the best predictors on MRI that can suspect malignant NAC invasion.

Results

Out of the 125 patients with breast cancer, 33 patients (26.4%) showed malignant NAC invasion. On basis of multivariate analysis, abnormal nipple enhancement, tumor nipple enhancement, tumor nipple distance ≤ 2 cm, and abnormal and asymmetric nipple morphology were all significant predictors of malignant NAC invasion (P < 0.001) with abnormal unilateral nipple enhancement as the most important independent MRI predictor of malignant NAC invasion (odds ratio = 61.07, 95% CI 12.81–291.22, P < 0.001). When combining more than positive suspicious MRI features, DCE-MRI had 66.6% sensitivity, 76% specificity, 50% PPV, 86.4% NPV, and 73.6% accuracy in prediction of malignant NAC invasion.

Conclusion

DCE-MRI could predict malignant NAC invasion with abnormal unilateral nipple enhancement as the most important independent MRI predictor.

Diagnostic Accuracy of Nonmass Enhancement at Breast MRI in Predicting Tumor Involvement of the Nipple: A Prospective Study in a Single Institution

Background Although nonmass enhancement (NME) extension to the nipple at preoperative MRI frequently leads to sacrifice of the nipple-areolar complex (NAC), its correlation with pathologically confirmed NAC involvement is unclear. Purpose To evaluate the diagnostic accuracy of using NME extension to the subareolar region at breast MRI to predict pathologic nipple involvement and the eligibility for nipple-sparing mastectomy. Materials and Methods From November 2017 to November 2019, the authors prospectively enrolled participants with breast cancer and NME within 2 cm of the nipple at breast MRI who underwent surgery that included removal of the NAC. The authors evaluated NME extensions that were ipsilateral and contiguous with the biopsy-proven tumor lesions on images acquired during the early contrast phases. Pathologic nipple involvement and the distance from the nipple to the nearest cancer cell were evaluated by using serial vertical sectioning of the area extending from the entire NAC to the tumor. The primary end point was the positive predictive value (PPV) of NME, which was calculated as follows: (number with pathologic nipple invasion and NME extension to the nipple at breast MRI/number with NME extension to the nipple at breast MRI) × 100. Results Of 64 women (mean age, 52 years ± 9.8 [standard deviation]), 49 (77%) had NME extension to the nipple at breast MRI. The PPV of NME extension to the nipple was 86% (42 of 49 women; 95% CI: 73, 94). Among the 15 participants without NME extension to the nipple, only one (7%) had pathologic nipple involvement. The diagnostic accuracy of using NME extension to the nipple was 88% (56 of 64 women; 95% CI: 77, 95). The radiologic distance correlated well with the pathologic distance (Spearman correlation coefficient = 0.71, P = .003). Conclusion Nonmass enhancement extension to the nipple base at preoperative MRI has a high positive predictive value for identifying tumor involvement of the nipple, a contraindication to nipple-sparing mastectomy. © RSNA, 2021 Online supplemental material is available for this article.

Comparison of the Magnetic Resonance Imaging Findings of Paget's Disease of the Breast and Malignant Tumor Invasion of the Nipple-Areola Complex

Objective

We aimed to investigate the distinction between Paget's disease of the breast (PDB) and malignant tumor invasion of nipple-areolar complex (MTION) with Magnetic resonance imaging (MRI) findings without the need for skin punch biopsy.

Materials and Methods

MRI findings of 16 patients with pathologically proven PDB and 11 patients with pathologically proven MTION were reviewed retrospectively. MRI images were assessed for nipple morphological changes; areolar-periareolar skin changes; thickness, classification, and kinetic characteristics of the nipple-areolar complex (NAC) enhancement; morphological pattern, size, and pathological diagnosis of concomitant malignant lesions; kinetic characteristics of the concomitant malignant lesions enhancement; continuity of enhancement between the nipple and closest concomitant malignant lesion; similarity of enhancement kinetics of the NAC and concomitant malignant lesions; and nipple-to-malignant lesion distance in both patient groups.

Results

Areolar-periareolar skin thickening was statistically different between the patient groups. Enhancement kinetic pattern was classified as persistent in four patients with MTION and plateau in seven patients with PDB. Moreover, NAC enhancement kinetic characteristics were statistically different between the groups. Invasive ductal carcinoma was detected in three patients with PDB and five patients with MTION. A statistically significant difference in malignant lesion pathological types was detected between the patient groups.

Conclusion

The significant MRI findings in patients with MTION diagnosed as invasive ductal carcinoma were areolar-periareolar skin thickening and asymmetric NAC enhancement with persistent kinetics pattern. In patients diagnosed with ductal carcinoma in situ, a plateau pattern of asymmetric NAC enhancement without any areolar-periareolar skin changes on MRI may indicate PDB.

Magnetic resonance imaging in the evaluation of pathologic nipple discharge: indications and imaging findings

Pathologic nipple discharge (PND) is typically unilateral, spontaneous, involves a single duct, and is serous or bloody in appearance. In patients with PND, breast MRI can be helpful as an additional diagnostic tool when conventional imaging with mammogram and ultrasound are negative. MRI is able to detect the etiology of nipple discharge in 56-61% of cases when initial imaging with mammogram and ultrasound are negative. Advantages to using MRI in evaluation of PND include good visualization of the retroareolar breast and better evaluation of posterior lesions which may not be well evaluated on mammograms and galactograms. It is also less invasive compared to central duct excision. Papillomas and nipple adenomas are benign breast masses that can cause PND and are well visualized on MRI. Ductal ectasia, and infectious etiologies such as mastitis, abscess, and fistulas are additional benign causes of PND that are well evaluated with MRI. MRI is also excellent for evaluation of malignant causes of PND including Paget's disease, ductal carcinoma in-situ and invasive carcinoma. MRI's high negative predictive value of 87-98.2% is helpful in excluding malignant etiologies of PND.

MIP image derived from abbreviated breast MRI: potential to reduce unnecessary sub-nipple biopsies during nipple-sparing mastectomy for breast cancer

OBJECTIVE

To determine the value of a maximum-intensity projection (MIP) image derived from abbreviated breast MRI for excluding occult nipple-areolar complex (NAC) involvement in patients with breast cancer.

METHODS

This prospective study included breast cancer patients with clinically normal NACs between April 2016 and May 2019. Abbreviated breast MRI was performed, and an MIP image was generated for each patient. MIP images were examined for the following features: asymmetric nipple enhancement, tumor-nipple distance (TND), tumor diameter, lesion type, location, and multifocality. Independent predictive MIP features for occult NAC involvement were identified by univariable and multivariable logistic regression analyses. Models based on independent predictive MIP features were developed, and their diagnostic performances were evaluated using ROC analysis. The utility of an MIP image for excluding occult NAC involvement was assessed by considering NPVs across patient subgroups.

RESULTS

Eight hundred forty-three patients (67 NAC-positive and 776 NAC-negative) were enrolled. On MIP images, asymmetric nipple enhancement (odds ratio, 6.098; p < 0.001) and TND (odds ratio, 0.564; p = 0.003) were independent predictors of occult NAC involvement. A parallel test model of "asymmetric nipple enhancement or TND ≤ 15 mm" yielded the highest AUC value (0.838) among prediction models. The NPV of MIP images for excluding occult NAC involvement was 99.5%, which was applicable across various patient subgroups.

CONCLUSIONS

A single MIP image derived from abbreviated breast MRI has utility for excluding occult NAC involvement in breast cancer patients and reducing the number of unnecessary sub-nipple biopsies in nipple-sparing mastectomy.

KEY POINTS

• On MIP images derived from abbreviated breast MRI, asymmetric nipple enhancement and tumor-nipple distance were independent predictors for occult nipple involvement in patients with breast cancer. • Negative findings on MIP image can help select patients at minimal risk of occult nipple involvement, for whom unnecessary intraoperative sub-nipple biopsies in nipple-sparing mastectomy can be omitted.

Contrast mammography in clinical practice: Current uses and potential diagnostic dilemmas

OBJECTIVE

This article will discuss the indications for Contrast Enhanced Spectral Mammography (CESM) with a focus on imaging interpretation including diagnostic dilemmas and pitfalls which may be encountered in practice.

CONCLUSION

Understanding potential diagnostic dilemmas and pitfalls of CESM allows for enhanced interpretation. The clinical utilization of Contrast Enhanced Spectral Mammography (CESM) has increased significantly over the last few years. CESM demonstrates comparable sensitivity and accuracy to magnetic resonance imaging (MRI) for the evaluation of breast cancer but is less time consuming and less expensive. Because of this, CESM is now being used in lieu of MRI for many diagnostic indicators including the evaluation of abnormal mammographic findings, extent of disease, and response to neoadjuvant therapy. Additionally, ongoing research into the role of CESM in asymptomatic screening for breast cancer is evolving. As this technique becomes more popular, focusing on appropriate technique and interpretation is important. This article reviews the current and potential roles of CESM. It provides examples of CESM utilized for diagnostic indications while highlighting diagnostic dilemmas, pitfalls, and artifacts that may be encountered when interpreting CESM images.

Multimodality approach to the nipple-areolar complex: a pictorial review and diagnostic algorithm

The anatomic and histologic characteristics of the nipple-areolar complex make this breast region special. The nipple-areolar complex can be affected by abnormal development and a wide spectrum of pathological conditions, many of which have unspecific clinical and radiological presentations that can present a challenge for radiologists. The nipple-areolar complex requires a specific imaging workup in which a multimodal approach is essential. Radiologists need to know the different imaging modalities used to study the nipple-areolar complex, as well as their advantages and limitations. It is essential to get acquainted with the acquisition technique for each modality and the spectrum of findings for the different conditions. This review describes and illustrates a combined clinical and radiological approach to evaluate the nipple-areolar complex, emphasizing the findings for the normal morphology, developmental abnormalities, and the most common benign and malignant diseases that can affect this region. We also present a diagnostic algorithm that enables a rapid, practical approach to diagnosing condition involving the nipple-areolar complex.

A Case of Asymmetric Nipple Enhancement as an Imaging Precursor to Invasive Ductal Carcinoma

On multidetector computed tomography (CT), it is important to scrutinize the imaged portions of the breasts. In recent years, the dramatic rise in CT imaging has led to the increased detection of incidental breast lesions. We describe a case of invasive ductal carcinoma that presented as stage IV cancer, and retrospective review of prior imaging study revealed asymmetric nipple enhancement on a trauma protocol CT chest acquired three years earlier. This report highlights the importance of being attentive to breast abnormalities on CT performed for indications other than breast disease and additionally focuses on the approach to address abnormal enhancement of the nipple areolar complex (NAC).

Role of diffusion-weighted imaging in prediction of nipple-areolar complex invasion by breast cancer

THE AIM OF THIS WORK

The aim of this work was to estimate the role of diffusion-weighted imaging (DWI) in predicting malignant invasion of the nipple-areolar complex (NAC) by underlying breast cancer.

MATERIAL AND METHODS

This prospective study included 70 female patients with breast cancer with a mean age of 45.8 years (range: 28-68). DWI of the breast was done for all patients. Apparent diffusion coefficient (ADC) maps were automatically constructed. The mean ADC values of NAC were independently measured by two observers who are experts in breast imaging and correlated with the results of histopathological examinations.

RESULTS

Both observers found a significantly lower ADC value of malignant NAC invasion (n = 18) when compared with free NAC (n = 52), with mean ADC value for malignant NAC invasion was 0.86 ± 0.35 × 10^-3 mm²/s and 0.84 ± 0.08 × 10^-3 mm²/s for observer one and two respectively versus mean ADC value of 1.34 ± 0.25 × 10^-3 mm²/s and 1.4 ± 0.26 × 10^-3 mm²/s for free NAC by observer one and two respectively (P-value =0.001). Observer one found that a cutoff ADC value of 1.05 × 0^-3 mm²/s can predict malignant NAC invasion with 0.975 AUC, 92.8% accuracy, 94.4% sensitivity, and 92.3% specificity. Observer two found that a cutoff ADC value of 0.95 × 10^-3 mm²/s can predict malignant NAC invasion with 0.992 AUC, 95.7% accuracy, 88.9% sensitivity, and 98.1% specificity.

CONCLUSION

DWI can predict malignant NAC invasion in patients with breast cancer.