Lesions of uncertain malignant potential in the breast (B3): what do we know?

B3 Breast Lesions: Positive Predictive Value and Follow-Up on a Large Single-Institution Series

INTRODUCTION

Lesions of uncertain malignant potential (B3) represent 10% of core needle biopsies (CNBs) or vacuum-assisted breast biopsies (VABBs). Traditionally, B3 lesions are operated on. This study investigated the association between B3 subtypes and malignancy to determine the best management.

METHODS

Pre- and postoperative histological reports from 226 patients, who had undergone excisional surgery for B3 lesions, following CNB or VABB, were retrospectively analyzed. The correlation between the CNB/VABB diagnosis and the final pathology was investigated, along with the correlation between malignancy upgrade and the type of mammographic lesion. The positive predictive value (PPV) of malignancy of B3 lesions was calculated by simple logistic regression. Patients without cancer diagnosis underwent a 7-y follow-up.

RESULTS

Pathology showed 171 (75.6%) benign and 55 (24.3%) malignant lesions. The PPV was 24.3% (P = 0.043), including 31 (13.7%) ductal carcinomas in situ and 24 (10.6%) invasive carcinomas. The most frequently upgraded lesions were atypical ductal hyperplasia, 34.2% (P = 0.004), followed by lobular intraepithelial neoplasia, 27.5% (P = 0.025). The median diameter of mammographic lesions was 1.5 [0.9-2.5] cm, while for surgical specimens, it was 5 [4-7] cm (P < 0.0001). Mammographic findings and histology showed a significant correlation (P = 0.038). After a 7-y follow-up, 15 (8.9%) patients developed carcinoma, and 7 patients (4%) developed a new B3 lesion.

CONCLUSIONS

We can conclude that atypical ductal hyperplasia and lobular intraepithelial neoplasia still require surgery for a significant PPV. Other types that lacked significance or confidence intervals were too wide to draw any conclusion.

Overview of incidental breast lesions

Screening mammography identifies early-stage breast cancers and is associated with reduced breast cancer mortality. An unintended consequence of breast screening is the detection and diagnosis of multiple incidental benign and malignant breast lesions, including the heterogenous group of incidental benign (B3) lesions with uncertain biological outcomes and malignant potential, for which management remains controversial. Recent shifts toward more conservative management approaches, including the identification of patients who can undergo observation after vacuum-assisted excision, has gained interest. This commentary provides an overview of incidental B3 lesions and summarizes the current management paradigms for them.

Lobular intraepithelial neoplasia: Outcomes and optimal management

INTRODUCTION

Lobular neoplasia is a term encompassing both atypical lobular hyperplasia and lobular carcinoma in situ. These pathological findings are of uncertain malignant potential and predispose to a higher lifetime risk of breast cancer. Debate surrounds the management of such lesions, with the rationale for diagnostic excision based on the possibility of upgrading to malignancy. In this study, we report the upgrade rate of these lesions and risk of subsequent development of breast cancer.

METHODS

This is a retrospective review of a prospectively maintained data base of all biopsies of breast screening-detected abnormalities in a single Irish breast-screening unit. We included all patients with lobular neoplasia on core needle biopsy who underwent diagnostic excision from 2005 to 2012. We excluded those who had concurrent high-risk lesions on biopsy. End points included upgrade rate and subsequent diagnosis of malignancy on follow-up.

RESULTS

During the study period, 66 patients met criteria for inclusion, with a mean age of 53.74 years. Upgrade rate following excision was 13.64% (n = 9/66). Of those not upgraded, 7.02% (n = 4/57) were subsequently diagnosed with malignancy. Median time to diagnosis was 59.61 months (range = 10.5-124.4).

CONCLUSION

There is a significant rate of upgrade following diagnostic excision of lobular neoplasia, supporting the practice of diagnostic excision. There is an increased lifetime risk of breast cancer for women with a diagnosis of lobular neoplasia, with many of these cancers occurring outside the standard five-year monitoring period, suggesting a potential benefit in extending surveillance.

Clinical value and application of contrast-enhanced ultrasound in the differential diagnosis of malignant and benign breast lesions

The aim of the present study was to assess the performance of contrast-enhanced ultrasound in distinguishing between malignant and benign breast lesions and the diagnostic value of its clinical application. A total of 52 cases with malignant breast tumors and 73 cases with benign breast lesions were included in the study. Time-intensity curves (TICs) for contrast-enhanced ultrasound were recorded, and the perfusion parameters were obtained and analyzed. Typical features of malignant breast tumors included irregular shape and vascular morphology, uneven contrast agent distribution, filling defects and contrast agent retention, ‘fast-out’ wash-out mode, unclear boundaries and uneven internal echo. Benign lesions were characterized by ‘slow-out’ or synchronous wash-out mode. Regarding perfusion, the starting time of the perfusion of the Sone-Vue microbubble contrast (always 20-30 sec) and time to peak (TTP) were significantly earlier for the malignant lesions, while the wash-out time was later. A significantly greater peak intensity, rising slope and area under the TIC were observed for the malignant breast lesions. All of the malignant breast lesions exhibited an enlarged focus scope on ultrasound, while no obvious focus scope enhancement was observed for benign breast lesions. Furthermore, the TICs of 88.4% of malignant breast lesions were of the fast-rising and slow-declining type, while the TICs of 75.3 and 17.8% of the benign breast lesions were of the slow-rising and fast-declining, and fast-rising and fast-declining type, respectively. Receiver operating characteristics analysis indicated that the TTP, wash-out time and rising slope might contribute to the differential diagnosis between malignant and benign breast lesions. In conclusion, TIC parameters of contrast-enhanced ultrasound have promising clinical value in differentiating between malignant and benign breast lesions. The TTP, wash-out time and rising slope may contribute to the diagnosis of patients with breast lesions to facilitate timely treatment and prognostication of breast cancer patients.

Image-guided breast biopsy and localisation: recommendations for information to women and referring physicians by the European Society of Breast Imaging

We summarise here the information to be provided to women and referring physicians about percutaneous breast biopsy and lesion localisation under imaging guidance. After explaining why a preoperative diagnosis with a percutaneous biopsy is preferred to surgical biopsy, we illustrate the criteria used by radiologists for choosing the most appropriate combination of device type for sampling and imaging technique for guidance. Then, we describe the commonly used devices, from fine-needle sampling to tissue biopsy with larger needles, namely core needle biopsy and vacuum-assisted biopsy, and how mammography, digital breast tomosynthesis, ultrasound, or magnetic resonance imaging work for targeting the lesion for sampling or localisation. The differences among the techniques available for localisation (carbon marking, metallic wire, radiotracer injection, radioactive seed, and magnetic seed localisation) are illustrated. Type and rate of possible complications are described and the issue of concomitant antiplatelet or anticoagulant therapy is also addressed. The importance of pathological-radiological correlation is highlighted: when evaluating the results of any needle sampling, the radiologist must check the concordance between the cytology/pathology report of the sample and the radiological appearance of the biopsied lesion. We recommend that special attention is paid to a proper and tactful approach when communicating to the woman the need for tissue sampling as well as the possibility of cancer diagnosis, repeat tissue sampling, and or even surgery when tissue sampling shows a lesion with uncertain malignant potential (also referred to as "high-risk" or B3 lesions). Finally, seven frequently asked questions are answered.

An audit of mammographic screen detected lesions of uncertain malignant potential (B3) diagnosed on initial image guided needle biopsy: how has our practice changed over 10 years?

AIM

To review all cases of B3 lesion diagnosed at initial image-guided needle biopsy over two 5-year cohorts to identify upgrade rates to malignancy and the effect of changing guidance on the management of such lesions.

MATERIALS AND METHODS

Data was collected retrospectively. Mammographic features, biopsy type and management were recorded for each lesion. Upgrade rates for each B3 histological category were quantified. Statistical analysis was performed using SPSS.

RESULTS

There were 224 cases in 2005-2010 and 240 cases in 2010-2015. Mammographically 211 lesions were microcalcifications, 182 masses, 65 distortions and six asymmetric densities with no difference in the mammographic features in the two cohorts. Two hundred and eight 14 G core biopsies and 256 initial vacuum-assisted biopsies were performed. There was a statistically significant reduction in benign surgical biopsies and an increase in second-line vacuum biopsy/excision in the latter cohort, with no significant change in the upgrade rate. There was an overall 6% upgrade to invasive malignancy and 13% upgrade to ductal carcinoma in situ (DCIS). The upgrade rates for the following histological categories were atypical intraductal epithelial proliferation (AIDEP) 33.2% (21/63); classical (not pleomorphic) in situ lobular neoplasia (ISLN) 18.2% (6/33); flat epithelial hyperplasia (FEA) 21.7% (20/92); papilloma with atypia 53.8% (7/13), without atypia 12.1% (8/66); and radial scar/complex sclerosing lesion with atypia 16.7% (2/12), and without atypia 7.9% (6/76).

CONCLUSION

Upgrade rates remain high for some histological categories even with first-line use of vacuum biopsy. Management of borderline lesions should be considered carefully in a multidisciplinary meeting. In many cases, the need for diagnostic surgical excision has been replaced by image-guided vacuum sampling.

Pre- and post-contrast versus post-contrast cone-beam breast CT: can we reduce radiation exposure while maintaining diagnostic accuracy?

OBJECTIVES

To evaluate whether post-contrast cone-beam breast CT (CBBCT) alone is comparable to the current standard of combined pre- and post-contrast CBBCT regarding diagnostic accuracy and superior regarding radiation exposure.

MATERIAL AND METHODS

This study included 49 women (61 breasts) with median age 57.9 years and BI-RADS 4/5 lesions diagnosed on mammography/ultrasound in density type c/d breasts. Two radiologists rated post-contrast CBBCT and pre- and post-contrast CBBCT with subtraction images on the BI-RADS scale separately for calculation of inter- and intra-observer agreement and in consensus for diagnostic accuracy assessment. Sensitivity, specificity, and area under the curve (AUC) were compared via McNemar test and DeLong method, respectively. Subtraction imaging misregistration were measured from 1 (no artifacts) to 4 (artifacts with width > 4 mm).

RESULTS

A total of 100 lesion (51 malignant; 6 high risk; 43 benign) were included. AUC, sensitivity, and specificity showed no significant differences comparing post-contrast CBBCT alone versus pre- and post-contrast CBBCT (AUC 0.84 vs. 0.83, p = 0.643; sensitivity 0.89 vs. 0.85, p = 0.158; specificity 0.73 vs. 0.76, p = 0.655). Inter- and intra-observer agreement was excellent (intra-class correlation coefficient ICC = 0.76, ICC = 0.83, respectively). Radiation dose was significantly lower for post-contrast CBBCT alone versus pre- and post-contrast CBBCT (median average glandular radiation dose 5.9 mGy vs. 11.7 mGy, p < 0.001). High-degree misregistrations were evident in the majority of subtraction images (level 1/2/3/4 16.9%/27.1%/16.9%/39%), in particular for bilateral exams (3.2%/29.2%/8.3%/58.3%).

CONCLUSION

Diagnostic accuracy of post-contrast CBBCT alone is comparable to pre- and post-contrast CBBCT in type c/d breasts, while yielding a significant twofold radiation dose reduction.

KEY POINTS

• The diagnostic accuracy of post-contrast CBBCT alone is comparable to dual acquisition of pre- and post-contrast CBBCT. • Acquisition of the post-contrast CBBCT scan alone reduces radiation exposure compared to pre- and post-contrast CBBCT, thus countering one of the main limitations of CBBCT. • High-degree misregistration artifacts limit the interpretation of subtraction images from pre- and post-contrast CBBCT studies.

Feasibility of Vacuum-Assisted Breast Cone-Beam CT-Guided Biopsy and Comparison With Prone Stereotactic Biopsy

OBJECTIVE

The feasibility of breast vacuum-assisted biopsy (VAB) guided by cone-beam CT (CBCT) was assessed. The initial clinical performance of CT-guided breast VAB was compared with that of established prone stereotactic VAB.

MATERIALS AND METHODS

In this retrospective clinical trial, VABs were performed for women with mammographically suspicious breast lesions using a dedicated breast CBCT protocol. The technical success rate, total intervention time, and complications were documented and compared with examinations performed by prone stereotactic VAB.

RESULTS

Between June 2015 and March 2016, 65 patients with 68 target lesions underwent image-guided VAB. CT-guided VAB was performed for 29 patients with 31 lesions. Thirty-six patients with 37 lesions underwent prone stereotactic VAB. The type of lesion was not different between the two groups (p = 0.135). Technical success rate was achieved in 31 of 33 lesions (93.9%) with CT-guided VAB versus 37 of 38 lesions (97.4%) with prone stereotactic VAB. The mean (± SD) total intervention time was 22.7 ± 8.4 minutes for CT-guided VAB versus 28.8 ± 9.4 minutes for prone stereotactic VAB (p < 0.05). Reidentifying and targeting lesions took about the same time for both systems (p = 0.362). The time for tissue sampling was significantly faster with CT-guided VAB (p < 0.05). No major complications were observed with either system.

CONCLUSION

CT-guided VAB is safe and feasible using the currently available breast CBCT protocol. The mean total intervention time to complete VAB and the time for tissue sampling was significantly faster using CT-guided VAB in comparison with prone stereotactic VAB.

The B3 conundrum-the radiologists' perspective

The management of B3 lesions is both controversial and complicated. There have been recent publications regarding how best to manage this heterogeneous group particularly in light of the Marmot Review and with the advent of vacuum-assisted biopsy technique. It is recognized that B3 lesions on core biopsy can be upgraded to malignancy in up to one-third of cases, but this is predominantly to ductal carcinoma in situ or low-grade invasive tumours. The upgrade rate is mainly associated with B3 lesions with epithelial atypia. This review summarizes the current management and focuses on the proposed future management of these B3 lesions.