Atypical ductal hyperplasia: breast DCE-MRI can be used to reduce unnecessary open surgical excision

Assessment of the contribution of the ADC value to the Kaiser score in the differential diagnosis of breast lesions with non-mass enhancement morphology on MRI

PURPOSE

To investigate the effectiveness of diffusion-weighted imaging (DWI) as a supplementary tool to the Kaiser score (KS) in diagnosing breast cancer in non-mass enhancement (NME) lesions using breast magnetic resonance imaging (MRI).

METHODS

This single-center, retrospective study analyzed 360 cases with NME on MRI images. Two breast radiologists independently evaluated each lesion using the Kaiser score (KS) and apparent diffusion coefficient (ADC) values, without knowledge of the pathological outcomes. NME lesions with a KS above 4 and an ADC value below 1.3 × 10-3mm2/s were classified as malignant. Inter-rater reliability was determined using Cohen's Kappa (κ) statistics. The diagnostic performance of KS, DWI, and their combination was assessed by calculating sensitivity, specificity, and the area under the curve (AUC), and the results were compared across the benign and malignant groups.

RESULTS

The diagnostic performance of KS surpassed that of DWI in predicting the malignancy of NMEs (p = 0.003). The sensitivity of KS alone was 93 %; however, when ADC data was incorporated, the sensitivity decreased to 86 %, with no significant difference observed (p = 0.060). The specificity of the combined KS and ADC (94 %) was significantly higher than that of KS alone (89 %) and DWI alone (73 %) (p < 0.001).

CONCLUSION

Our findings indicated that although the combination of KS and ADC increased specificity and reduced unnecessary biopsies, the resulting decrease in sensitivity was unacceptable. Therefore, KS alone is superior to the KS-ADC combination in detecting malignancy in NME lesions.

Contrast-enhanced ultrasound to predict malignant upgrading of atypical ductal hyperplasia

BACKGROUND

A malignancy might be found at surgery in cases of atypical ductal hyperplasia (ADH) diagnosed via US-guided core needle biopsy (CNB). The objective of this study was to investigate the diagnostic performance of contrast-enhanced ultrasound (CEUS) in predicting ADH diagnosed by US-guided CNB that was upgraded to malignancy after surgery.

METHODS

In this retrospective study, 110 CNB-diagnosed ADH lesions in 109 consecutive women who underwent US, CEUS, and surgery between June 2018 and June 2023 were included. CEUS was incorporated into US BI-RADS and yielded a CEUS-adjusted BI-RADS. The diagnostic performance of US BI-RADS and CEUS-adjusted BI-RADS for ADH were analyzed and compared.

RESULTS

The mean age of the 109 women was 49.7 years ± 11.6 (SD). The upgrade rate of ADH at CNB was 48.2% (53 of 110). The sensitivity, specificity, positive predictive value, and negative predictive value of CEUS for identification of malignant upgrading were 96.2%, 66.7%,72.9%, and 95.0%, respectively, based on BI-RADS category 4B threshold. The two false-negative cases were low-grade ductal carcinoma in situ. Compared with the US, CEUS-adjusted BI-RADS had better specificity for lesions smaller than 2 cm (76.7% vs. 96.7%, P = 0.031). After CEUS, 16 (10 malignant and 6 nonmalignant) of the 45 original US BI-RADS category 4A lesions were up-classified to BI-RADS 4B, and 3 (1 malignant and 2 nonmalignant) of the 41 original US BI-RADS category 4B lesions were down-classified to BI-RADS 4A.

CONCLUSIONS

CEUS is helpful in predicting malignant upgrading of ADH, especially for lesions smaller than 2 cm and those classified as BI-RADS 4A and 4B on ultrasound.

Problem-solving Breast MRI

Breast MRI has high sensitivity and negative predictive value, making it well suited to problem solving when other imaging modalities or physical examinations yield results that are inconclusive for the presence of breast cancer. Indications for problem-solving MRI include equivocal or uncertain imaging findings at mammography and/or US; suspicious nipple discharge or skin changes suspected to represent an abnormality when conventional imaging results are negative for cancer; lesions categorized as Breast Imaging Reporting and Data System 4, which are not amenable to biopsy; and discordant radiologic-pathologic findings after biopsy. MRI should not precede or replace careful diagnostic workup with mammography and US and should not be used when a biopsy can be safely performed. The role of MRI in characterizing calcifications is controversial, and management of calcifications should depend on their mammographic appearance because ductal carcinoma in situ may not appear enhancing on MR images. In addition, ductal carcinoma in situ detected solely with MRI is not associated with a higher likelihood of an upgrade to invasive cancer compared with ductal carcinoma in situ detected with other modalities. MRI for triage of high-risk lesions is a subject of ongoing investigation, with a possible future role for MRI in decreasing excisional biopsies. The accuracy of MRI is likely to increase with the use of advanced techniques such as deep learning, which will likely expand the indications for problem-solving MRI. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Imaging Characteristics of and Multidisciplinary Management Considerations for Atypical Ductal Hyperplasia and Flat Epithelial Atypia: Review of Current Literature

High-risk lesions of the breast are frequently encountered in percutaneous biopsy specimens. While benign, these lesions have historically undergone surgical excision due to their potential to be upgraded to malignancy. However, there is emerging evidence that a tailored management approach should be considered to reduce overtreatment of these lesions. Flat epithelial atypia (FEA) and atypical ductal hyperplasia (ADH) are two of the most commonly encountered high-risk lesions. FEA has been shown to have a relatively low rate of progression to malignancy, and some guidelines are now recommending observation over routine excision in select cases. Selective observation may be reasonable in cases where the target lesion is small and completely removed at biopsy and when there are no underlying risk factors, such as a history of breast cancer or genetic mutation or concurrent ADH. ADH has the highest potential upgrade rate to malignancy of all the high-risk lesions. Most society guidelines continue to recommend surgical excision of this lesion. More recently, some literature suggests that ADH lesions that appear completely removed at biopsy, involve limited foci (less than two or three) with no necrosis or significant atypia, manifest as a small group of mammographic calcifications, or demonstrate no enhancement at MRI may be reasonable for observation. Ultimately, management of all high-risk lesions must be based on a multidisciplinary approach that considers all patient, radiologic, clinical, and histopathologic factors. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Active Surveillance for Atypical Ductal Hyperplasia and Ductal Carcinoma In Situ

Atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS) are relatively common breast lesions on the same spectrum of disease. Atypical ductal hyperblasia is a nonmalignant, high-risk lesion, and DCIS is a noninvasive malignancy. While a benefit of screening mammography is early cancer detection, it also leads to increased biopsy diagnosis of noninvasive lesions. Previously, treatment guidelines for both entities included surgical excision because of the risk of upgrade to invasive cancer after surgery and risk of progression to invasive cancer for DCIS. However, this universal management approach is not optimal for all patients because most lesions are not upgraded after surgery. Furthermore, some DCIS lesions do not progress to clinically significant invasive cancer. Overtreatment of high-risk lesions and DCIS is considered a burden on patients and clinicians and is a strain on the health care system. Extensive research has identified many potential histologic, clinical, and imaging factors that may predict ADH and DCIS upgrade and thereby help clinicians select which patients should undergo surgery and which may be appropriate for active surveillance (AS) with imaging. Additionally, multiple clinical trials are currently underway to evaluate whether AS for DCIS is feasible for a select group of patients. Recent advances in MRI, artificial intelligence, and molecular markers may also have an important role to play in stratifying patients and delineating best management guidelines. This review article discusses the available evidence regarding the feasibility and limitations of AS for ADH and DCIS, as well as recent advances in patient risk stratification.

Breast MRI assists in decision-making for surgical excision of atypical ductal hyperplasia

BACKGROUND

Atypical ductal hyperplasia diagnosed on percutaneous breast biopsy typically undergoes surgical excision, upgrading to invasive breast cancer or ductal carcinoma in situ in 10% to 53%. In efforts to limit excision to those with highest upgrade risk, we sought to determine if breast magnetic resonance imaging has value in predicting upgrade. In this study, we will describe magnetic resonance imaging presentation of atypical ductal hyperplasia and assess magnetic resonance imaging accuracy in predicting upgrade.

METHODS

All female patients ≥18 years with atypical ductal hyperplasia on percutaneous breast biopsy undergoing magnetic resonance imaging from 2008 to 2020 were included. Patient demographics, imaging presentation, magnetic resonance imaging enhancement kinetic curves, and pathology features were captured. Categorical variables were analyzed using Fisher exact to test for association between variables and upgrade. Continuous variables were analyzed using t tests.

RESULTS

Magnetic resonance imaging was performed for 125 percutaneous breast biopsy with atypical ductal hyperplasia: 67 after and 58 before atypical ductal hyperplasia diagnosis. On magnetic resonance imaging, atypical ductal hyperplasia site had no enhancement in 45 (36%), nonmass enhancement in 50 (40%), and mass enhancement in 30 (24%). In total, 28% had atypical ductal hyperplasia diagnosed by magnetic resonance imaging-guided percutaneous breast biopsy. Surgical excision was performed for 96 (76.8%) and 15 (15.6%) upgraded (11 ductal carcinoma in situ, 4 invasive breast cancer). All 15 upgrades had enhancement. Any kinetic pattern enhancement was significantly associated with upgrade (P = .009) with upgrade most strongly associated with type III washout. The lowest risk for upgrade was pure atypical ductal hyperplasia and no magnetic resonance imaging enhancement (0%, n = 25).

CONCLUSIONS

Active monitoring may be safely offered to women with pure atypical ductal hyperplasia on percutaneous breast biopsy when magnetic resonance imaging shows no enhancement. Any enhancement at atypical ductal hyperplasia site, particularly type III washout kinetics, should continue to undergo excision.

High-Risk Lesion Management

High-risk lesions or lesions of uncertain malignant potential are frequent findings on image-guided needle biopsy of the breast and comprise a number of distinct entities. These lesions are known for having risk of underlying malignancy and are usually associated with an increased lifetime risk for breast cancer. Surgical excision was traditionally recommended for all high-risk lesions but recent studies have demonstrated that vacuum-assisted excision or surveillance may be adequate for some lesions. While management of high-risk lesion varies among institutions, this chapter describes the management recommendations based on recent literature of the most frequent types of lesions.

B3 Lesions at Vacuum-Assisted Breast Biopsy under Ultrasound or Mammography Guidance: A Single-Center Experience on 3634 Consecutive Biopsies

The rate of upgrade to cancer for breast lesions with uncertain malignant potential (B3 lesions) diagnosed at needle biopsy is highly influenced by several factors, but large series are seldom available. We retrospectively assessed the upgrade rates of a consecutive series of B3 lesions diagnosed at ultrasound- or mammography-guided vacuum-assisted biopsy (VAB) at an EUSOMA-certified Breast Unit over a 7-year timeframe. The upgrade rate was defined as the number of ductal carcinoma in situ (DCIS) or invasive cancer at pathology after excision or during follow-up divided by the total number of B3 lesions. All lesions were reviewed by one of four pathologists with a second opinion for discordant assessments of borderline cases. Excision or surveillance were defined by the multidisciplinary tumor board, with 6- and 12-month follow-up. Out of 3634 VABs (63% ultrasound-guided), 604 (17%) yielded a B3 lesion. After excision, 17/604 B3 lesions were finally upgraded to malignancy (2.8%, 95% confidence interval [CI] 1.8-4.5%), 10/17 (59%) being upgraded to DCIS and 7/17 (41%) to invasive carcinoma. No cases were upgraded during follow-up. B3a lesions showed a significantly lower upgrade rate (0.4%, 95% CI 0.1-2.1%) than B3b lesions (4.7%, 95% CI 2.9-7.5%, p = 0.001), that had a 22.0 adjusted odds ratio for upgrade (95% CI 2.1-232.3). No significant difference was found in upgrade rates according to imaging guidance or needle caliper. Surveillance-oriented management can be considered for B3a lesions, while surgical excision should be pursued for B3b lesions.

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.

Positive predictive value for malignancy of uncertain malignant potential (B3) breast lesions diagnosed on vacuum-assisted biopsy (VAB): is surgical excision still recommended?

PURPOSE

Breast lesions classified as of "uncertain malignant potential" represent a heterogeneous group of abnormalities with an increased risk of associated malignancy. Clinical management of B3 lesions diagnosed on vacuum-assisted breast biopsy (VABB) is still challenging: surgical excision is no longer the only available treatment and VABB may be sufficient for therapeutic excision. The aim of the present study is to evaluate the positive predictive value (PPV) for malignancy in B3 lesions that underwent surgical excision, identifying possible upgrading predictive factors and characterizing the malignant lesions eventually diagnosed. These results are compared with a subset of patients with B3 lesions who underwent follow-up.

METHODS

A total of 1250 VABBs were performed between January 2006 and December 2017 at our center. In total, 150 B3 cases were diagnosed and 68 of them underwent surgical excision. VABB findings were correlated with excision histology. A PPV for malignancy for each B3 subtype was derived.

RESULTS

The overall PPV rate was 28%, with the highest upgrade rate for atypical ductal hyperplasia (41%), followed by classical lobular neoplasia (29%) and flat epithelial atypia (11%). Only two cases of carcinoma were detected in the follow-up cohort, both associated with atypical ductal hyperplasia at VABB.

CONCLUSION

Open surgery is recommended in case of atypical ductal hyperplasia while, for other B3 lesions, excision with VABB only may be an acceptable alternative if radio-pathological correlation is assessed, if all microcalcifications have been removed by VABB, and if the lesion lacks high-risk cytological features.

KEY POINTS

• Surgical treatment is strongly recommended in case of ADH, while the upgrade rate in case of pure FEA, especially following complete microcalcification removal by VABB, may be sufficiently low to advice surveillance as a management strategy. • The use of 11-G- or 8-G-needle VABB, resulting in possible complete diagnostic excision of the lesion, can be an acceptable alternative in case of RS, considering open surgery only for selected high-risk patients. • LN management is more controversial: surgical excision may be recommended following classical LN diagnosis on breast biopsy if an additional B3 lesion is concurrently detected while in the presence of isolated LN with adequate radiological-pathological correlation follow-up alone could be an acceptable option.

An update on the management of breast atypical ductal hyperplasia

Among lesions with uncertain malignant potential found at percutaneous breast biopsy, atypical ductal hyperplasia (ADH) carries both the highest risk of underestimation and the closest and most pathologist-dependent differential diagnosis with ductal carcinoma in situ (DCIS), matching the latter's features save for size only. ADH is therefore routinely surgically excised, but single-centre studies with limited sample size found low rates of upgrade to invasive cancer or DCIS. This suggests the possibility of surveillance over surgery in selected subgroups, considering the 2% threshold allowing for follow-up according to the Breast Imaging Reporting and Data System. A recent meta-analysis on 6458 lesions counters this approach, confirming that, surgically excised or managed with surveillance, ADH carries a 29% and 5% upgrade rate, respectively, invariably higher than 2% even in subgroups considering biopsy guidance and technique, needle calibre, apparent complete lesion removal. The high heterogeneity (I2 = 80%) found in this meta-analysis reaffirmed the need to synthesise evidence from systematic reviews to achieve generalisable results, fit for guidelines development. Limited tissue sampling at percutaneous biopsy intrinsically hampers the prediction of ADH-associated malignancy. This prediction could be improved by using contrast-enhanced breast imaging and applying artificial intelligence on both pathology and imaging results, allowing for overtreatment reduction.