Malignancy rates of B3-lesions in breast magnetic resonance imaging - do all lesions have to be excised?

Lobular Neoplasia Diagnosed by MRI-Guided Breast Biopsy: Identifying Upgrade Rate to Malignancy and Outcomes of Clinical and Surgical Management

OBJECTIVE

The aim of this study was to determine surgical and clinical outcomes of lobular neoplasia (LN) diagnosed by magnetic resonance imaging (MRI) biopsy, including upgrade to malignancy, and to assess for characteristics associated with upgrade.

METHOD

A single-institution retrospective study, between 2013 and 2022, of patients with histopathological findings of LN via MRI-guided biopsy was performed using an institutional database and review of the electronic medical records. Decision for excision or surveillance was made by a multidisciplinary team per institutional practice. Patient demographics and imaging characteristics were summarized using descriptive analyses. Upgrade was defined as upgrade to cancer on surgical pathology for patients treated with excision or the development of cancer at the biopsy site during surveillance. The Wilcoxon rank-sum test and Fisher's exact test were used to compare features of the upgraded cohort with the remainder of the group.

RESULTS

Ninety-four MRI biopsies diagnosing LN were included. Median age was 57 years (range 37-78 years). Forty-six lesions underwent excision while 48 lesions were surveilled. The upgrade rate was 7.4% (7/94). Upgrades in the excised cohort consisted of pleomorphic lobular carcinoma in situ (LCIS; n = 1), ductal carcinoma in situ (DCIS; n = 3) and invasive lobular carcinoma (ILC; n = 2), while one interval development of DCIS was observed at the site of biopsy in the surveillance cohort. No MRI or patient variables were associated with upgrade.

CONCLUSIONS

In this contemporary cohort of MRI-detected LNs, the upgrade rate was low. Omission of surgery for MRI-detected LNs in carefully selected patients may be considered in a shared decision-making capacity between the patient and the treatment team. Larger cohorts are needed to determine factors predictive of upgrade risk.

Update on Lobular Neoplasia

Lobular neoplasia (LN) is a histopathologic entity that encompasses both lobular carcinoma in situ (LCIS) and atypical lobular hyperplasia (ALH). Management of LN is known to be variable and institutionally dependent. The variability in approach after a diagnosis of LN at percutaneous breast biopsy derives in part from heterogeneity in the literature, resulting in a range of reported upgrade rates to malignancy after initial identification at percutaneous biopsy, and also from historical shifts in understanding of the natural history of LN. It has become increasingly recognized that not all LN is the same and that distinct variants of LN such as pleomorphic LCIS and florid LCIS have distinct natural histories and distinct likelihoods of upgrade to malignancy. In addition, it is also increasingly understood that appropriate management of LN relies on scrupulous radiologic-pathologic correlation. This review details the imaging features and histopathologic nature of ALH, classic-type LCIS, and the LCIS variants; addresses changes in the historical understanding of this entity contributing to confusion regarding its management; and discusses the importance of performing radiologic-pathologic correlation after percutaneous biopsy to help guide appropriate management steps when LN is encountered. In addition to the short-term implications of an LN diagnosis in terms of upgrade and surgical outcomes, the long-term implications of an LN diagnosis regarding risk of developing a later breast cancer are examined. ©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Breast Lesions of Uncertain Malignant Potential (B3) and the Risk of Breast Cancer Development: A Long-Term Follow-Up Study

Breast lesions of uncertain malignant potential (B3) are frequently diagnosed in the era of breast cancer (BC) screening and their management is controversial. They are generally removed surgically, but some international organizations and guidelines for breast research suggest follow-up care alone or, more recently, propose vacuum-assisted excision (VAE). The risk of upgrade to BC is known, but very little data exist on its role as risk factor for future BC development. We analyzed 966 B3 lesions diagnosed at our institution, 731 of which had long-term follow-up available. Surgical removal was performed in 91%, VAE in 3.8%, and follow-up in 5.2% of cases. The B3 lesions included flat epithelial atypia (FEA), atypical ductal hyperplasia (ADH), lobular intraepithelial neoplasia (LIN), atypical papillary lesions (PLs), radial scars (RSs), and others. Overall, immediate upgrade to BC (invasive or in situ) was 22.7%. After long-term follow-up, 9.2% of the patients were diagnosed with BC in the same or contralateral breast. The highest risk was associated with ADH diagnosis, with 39.8% of patients upgraded and 13.6% with a future BC diagnosis (p < 0.0001). These data support the idea that B3 lesions should be removed and provide evidence to suggest annual screening mammography for women after a B3 diagnosis because their BC risk is considerably increased.

Rethinking Routine Surgical Excision for all Radial Sclerosing Lesions of the Breast

INTRODUCTION

The need for routine surgical excision of a radial sclerosing lesions (RSL) of the breast identified on percutaneous biopsy remains controversial, as contemporary upgrade rates are lower than historically cited.

MATERIALS AND METHODS

A prospectively-maintained database of high-risk breast biopsies undergoing multidisciplinary review at a single institution was queried to identify cases of RSL from 2/2015 to 11/2020. Demographic, radiologic, and pathologic variables were summarized using frequencies and analyzed in association with RSL excision status using mixed-effects logistic regression or Fisher's exact tests.

RESULTS

217 RSL were identified, diagnosed at a mean age of 57 y. The median imaging size was 1.3 cm and the majority had estimated >50% of the target removed by core needle biopsy. 32.3% underwent surgical excision of the RSL biopsy site and 2/70 (2.9%) upgraded to ductal carcinoma in situ (DCIS) on final surgical pathology. Upgrade was significantly higher for atypical RSL (P = 0.02). None of the RSL (n = 60) without atypia who had undergone excision were upgraded. For those omitting surgical excision, there was no subsequent breast cancer diagnosis at the RSL site over a mean follow-up of 23 mo.

CONCLUSIONS

Surgical excision may be omitted for RSL without atypia as this group has 0% risk of upgrade after multidisciplinary review.

A simplified scoring protocol to improve diagnostic accuracy with the breast imaging reporting and data system in breast magnetic resonance imaging

BACKGROUND

The breast imaging reporting and data system (BI-RADS) lexicon provides a standardized terminology for describing leision characteristics but does not provide defined rules for converting specific imaging features into diagnostic categories. The inter-reader agreement of the BI-RADS is moderate. In this study, we explored the use of a simplified protocol and scoring system for BI-RADS categorization which integrates the morphologic features (MF), kinetic time-intensity curve (TIC), and apparent diffusion coefficient (ADC) values with equal weights, with a view to providing a convenient and practical method for breast magnetic resonance imaging (MRI) and improving the inter-reader agreement and diagnostic performance of BI-RADS.

METHODS

This cross-sectional, retrospective, single-center study included 879 patients with 898 histopathologically verified lesions who underwent an MRI scan on a 3.0 Tesla GE Discovery 750 MRI scanner between January 1, 2017, and June 30, 2020. The BI-RADS categorization of the studied lesions was assessed according to the sum of the assigned scores (the presence of malignant MF, lower ADC, and suspicious TIC each warranted a score of +1). Total scores of +2 and +3 were classified as category 5, scores of +1 were classified as category 4, and scores of +0 but with other lesions of interest were classified as category 3. The receiver operating characteristic (ROC) curves were plotted, and the sensitivity, specificity, and accuracy of this categorization were investigated to assess its efficacy and its consistency with pathology.

RESULTS

There were 472 malignant, 104 risk, and 322 benign lesions. Our simplified scoring protocol had high diagnostic accuracy, with an area under curve (AUC) value of 0.896. In terms of the borderline effect of pathological risk and category 4 lesions, our results showed that when risk lesions were classified together with malignant ones, the AUC value improved (0.876 vs. 0.844 and 0.909 vs. 0.900). When category 4 and 5 lesions were classified as malignant, the specificity, accuracy, and AUC value decreased (82.3% vs. 93.2%, 89.3% vs. 90.2%, and 0.876 vs. 0.909, respectively). Therefore, to improve the diagnostic accuracy of the protocol for BI-RADS categorization, only category 5 lesions should be considered to be malignant.

CONCLUSIONS

Our simplified scoring protocol that integrates MF, TIC, and ADC values with equal weights for BI-RADS categorization could improve both the diagnostic performance of the protocol for BI-RADS categorization in clinical practice and the understanding of the benign-risk-malignant breast diseases.

Upgrade rate of percutaneously diagnosed pure flat epithelial atypia: systematic review and meta-analysis of 1,924 lesions

CONTEXT

Management remains controversial due to the risk of upgrade for malignancy from flat epithelial atypia (FEA). Data about the frequency and malignancy upgrade rates are scant. Namely, observational follow-up is advised by many studies in cases of pure FEA on core biopsy and in the absence of an additional surgical excision. For cases of pure FEA, the American College of Surgeons no longer recommends surgical excision but rather recommends observation with clinical and imaging follow-up.

OBJECTIVES

The aim of this study is to perform a systematic review and meta-analysis to calculate the pooled upgrade of pure FEA following core needle biopsies.

METHODS

A search of MEDLINE and Embase databases were conducted in December 2020. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. A fixed- or random-effects model was utilized. Heterogeneity among studies was estimated by utilizing the I2 statistic and considered high if the I2 was greater than 50%. The random-effects model with the DerSimonian and Laird method was utilized to calculate the pooled upgrade rate and its 95% confidence interval.

RESULTS

A total of 1924 pure FEA were analyzed among 59 included studies. The overall pooled upgrade rate to malignancy was 8.8%. The pooled upgrade rate for mammography only was 8.9%. The pooled upgrade rate for ultrasound was 14%. The pooled upgrade rate for mammography and ultrasound combined was 8.8%. The pooled upgrade rate for MRI-only cases was 27.3%.

CONCLUSIONS

Although the guidelines for the management of pure FEA are variable, our data support that pure FEA diagnosed at core needle biopsy should undergo surgical excision since the upgrade rate >2%.

Role of breast MRI in predicting histologic upgrade risks in high-risk breast lesions: A review

PURPOSE

This article reviews the frequency, upgrade rate and valuable imaging characteristics for predicting the histologic upgrade risks of high-risk lesions on MRI, so as to provide a reference for the management of the lesions.

METHODS

A comprehensive search for relevant publications from January 2011 to January 2021 was conducted in the PubMed database. The frequency, upgrade rate and valuable imaging characteristics for predicting the upgrade risks of high-risk lesions on MRI included in the articles were reviewed, and the management of high-risk lesions was provided with a reference according to the review results.

RESULTS AND CONCLUSIONS

In terms of management options, Atypical ductal hyperplasia (ADH) and Lobular neoplasia (LN) (the top two high-risk lesions with the highest upgrade rate and frequency) were treated with surgical resection. However, the final treatment decision for other high-risk lesions should be made by a multidisciplinary committee. In terms of the value of breast MRI in predicting the upgrade risks of high-risk lesions, the lesions that were confirmed to upgrade after surgery showed some enhancement characteristics, especially for ADH and LN. At the same time, Dynamic contrast-enhanced MRI (DCE-MRI) has a high negative predictive value (NPV) in predicting the upgrade risks of the high-risk lesions, hence misdiagnosis and overtreatment can be reduced. Diffusion-weighted imaging (DWI) and relative apparent diffusion coefficient (rADC) can be used to predict the upgrade risks of the lesions, and the ADC of upgraded lesions is lower than that of non-upgraded lesions. However, these conclusions should be confirmed by further studies.

[Interventional techniques for the breast]

BACKGROUND

Interventional methods of the breast serve as percutaneous minimally invasive diagnostic tools in case of suspicious findings in the breast or axilla. Further indications are lesion localization and the minimally invasive therapeutic approach.

OBJECTIVES

Aim of this paper is to give an overview of the existing methods, their indications and the imaging techniques for guidance. On the basis of the most recent publications, clinical management is described.

B3 lesion upgrade rates in a tertiary Australian breast centre: a 8-year experience (2012-2019)

BACKGROUND

B3 breast lesions identified on core needle biopsy have uncertain malignant potential. Traditional management of these lesions has been surgical excision, but there is growing interest in less invasive and more cost-effective alternatives such as vacuum-assisted excisional biopsy (VAEB). Determining the rate of malignant upgrade for B3 lesions is important as it may identify low-risk lesions where VAEB could be considered.

METHODS

A retrospective study was conducted of women undergoing an elective excisional biopsy for a B3 lesion identified on core needle biopsy at a tertiary Australian breast centre. The pre-operative biopsy diagnosis and subsequent excisional biopsy diagnosis were used to calculate the proportion of cases where the diagnosis was upgraded to malignancy.

RESULTS

A total of 299 eligible patients were identified. Pre-operative diagnosis of papillary lesion with atypia was associated with the highest upgrade rate (50%, n = 12). The next highest upgrade rates occurred in those with flat epithelial atypia (37.50%, n = 8); atypical ductal hyperplasia (24.71%, n = 85); lobular carcinoma in situ (LCIS)/atypical lobular hyperplasia with calcification (17.65%, n = 17); and papillary lesion without atypia (4.72%, n = 106). Patients with radial scar (n = 51), classical LCIS without calcification (n = 7) and mucocoele-like lesion (n = 8) had a 0% upgrade rate.

CONCLUSION

VAEB may be appropriate for low malignant risk lesions such as papillary lesion without atypia, mucocoele-like lesion and radial scar lesion without atypia. Open-surgical-excisional biopsy remains appropriate for high upgrade lesions such as atypical ductal hyperplasia, papillary lesion with atypia, flat epithelial atypia and classical LCIS with calcification. Long-term prospective randomized multicentre studies and continuing multidisciplinary approach is recommended for future clinical implementation.

Upgrade Rate of Percutaneously Diagnosed Pure Atypical Ductal Hyperplasia: Systematic Review and Meta-Analysis of 6458 Lesions

Background Management of percutaneously diagnosed pure atypical ductal hyperplasia (ADH) is an unresolved clinical issue. Purpose To calculate the pooled upgrade rate of percutaneously diagnosed pure ADH. Materials and Methods A search of MEDLINE and EMBASE databases was performed in October 2018. Preferred Reporting Items for Systematic Reviews and Meta-Analyses, or PRISMA, guidelines were followed. A fixed- or random-effects model was used, along with subgroup and meta-regression analyses. The Newcastle-Ottawa scale was used for study quality, and the Egger test was used for publication bias. Results Of 521 articles, 93 were analyzed, providing data for 6458 ADHs (5911 were managed with surgical excision and 547 with follow-up). Twenty-four studies used core-needle biopsy; 44, vacuum-assisted biopsy; 21, both core-needle and vacuum-assisted biopsy; and four, unspecified techniques. Biopsy was performed with stereotactic guidance in 29 studies; with US guidance in nine, with MRI guidance in nine, and with mixed guidance in eight. Overall heterogeneity was high (I² = 80%). Subgroup analysis according to management yielded a pooled upgrade rate of 29% (95% confidence interval [CI]: 26%, 32%) for surgically excised lesions and 5% (95% CI: 4%, 8%) for lesions managed with follow-up (P < .001). Heterogeneity was entirely associated with surgically excised lesions (I² = 78%) rather than those managed with follow-up (I² = 0%). Most variability was explained by guidance and needle caliper (P = .15). At subgroup analysis of surgically excised lesions, the pooled upgrade rate was 42% (95% CI: 31%, 53%) for US guidance, 23% (95% CI: 19%, 27%) for stereotactic biopsy, and 32% (95% CI: 22%, 43%) for MRI guidance, with heterogeneity (52%, 63%, and 56%, respectively) still showing the effect of needle caliper. When the authors considered patients with apparent complete lesion removal after biopsy (subgroups in 14 studies), the pooled upgrade rate was 14% (95% CI: 8%, 23%). Study quality was low to medium; the risk of publication bias was low (P = .10). Conclusion Because of a pooled upgrade rate higher than 2% (independent of biopsy technique, needle size, imaging guidance, and apparent complete lesion removal), atypical ductal hyperplasia diagnosed with percutaneous needle biopsy should be managed with surgical excision. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Brem in this issue.

Our Radiological Experience on B3 Lesions: Correlation Between Mammographic and MRI Findings With Histologic Definitive Result

INTRODUCTION

The purpose of this study was to evaluate mammographic and magnetic resonance imaging (MRI) features in B3 lesions.

PATIENTS AND METHODS

From 2011 to 2018, 139 patients with histologically proven B3 lesions who underwent mammography or/and MRI, were retrospectively reviewed. B3 lesions were classified in: atypical ductal hyperplasia (ADH), lobular neoplasia (LN), papillary lesion (PL), radial scar (RS), flat epithelial atypia (FEA), phyllodes tumor (PT), or mesenchymal lesion. Imaging features evaluated were: the presence of microcalcifications, mass and architectural distortions on mammograms and type of margins (circumscribed, irregular, spiculate), enhancement (mass-like, non-mass-like), size (≤ 15 mm, > 15 mm), and kinetics curves (I, II, III) on MRI. The definitive histologic results confirmed benign lesion or were upgraded to malignancy, and the positive predictive value was calculated.

RESULTS

Histologic classification of B3 lesions counted 45 (32.37%) ADH, 12 (8.63%) LN, 25 (17.99%) PL, 5 (3.61%) RS, 31 (22.31%) FEA, 20 (14.39%) PT, and 1 (0.70%) mesenchymal lesion. One hundred seven patients had mammography, and 38 had MRI. In 90 (65%) cases, the histologic diagnosis confirmed B3, in 15 (11%) cases, benign lesion, and in 34 (24%) cases, malignancies were found, with best positive predictive value for mesenchymal tumor (1), ADH (0.36), and FEA (0.4). Significant correlations comparing core needle biopsy groups and microcalcifications (P = .016) and presence of mass (P = .002) and comparing definitive histology with the presence of mass (P = .023), were found. Regarding MRI, the morphology correlated with core needle biopsy groups (P = .038); morphology (P = .024), dimension (P = .040), and kinetic curve (P = .005) correlated with malignancy.

CONCLUSIONS

The B3 category includes different entities, with various risk of malignancy; their heterogeneity is associated with specific mammographic and MRI features, although further confirmations are needed.