Can breast MRI predict pathologic response following neoadjuvant chemotherapy for breast cancer? A retrospective cohort study.

PURPOSE: For patients treated with neoadjuvant chemotherapy (NAC) for breast cancer, it is standard of care to perform pre- and post-NAC imaging to evaluate response to therapy prior to surgery. In this study we assess outcome metrics of magnetic resonance imaging (MRI) following NAC. METHODS: We conducted a retrospective analysis of patients with invasive breast cancer who underwent a breast MRI before and after NAC between 2016 and 2021 at a single, multisite academic institution. All breast MRI studies were characterized as either radiologic complete response (rCR) or non-rCR. Corresponding surgical pathology reports were reviewed and categorized as pathologic complete response (pCR) or non-pCR. We defined a positive test as having residual enhancement on MRI (non-rCR) and a positive outcome as having residual disease on final surgical pathology (non-pCR). RESULTS: There were 225 patients included in the study (mean age 52 ± 12 years). Breast cancer receptor distribution was HR+/HER2- (n = 71, 32%), HR+/HER2+ (n = 51, 23%), HR-/HER2- (n = 72, 32%), and HR-/HER2+ (n = 31, 14%). In total, 78 (35%) had rCR and 77 (34%) had pCR; 43 (19%) had both rCR and pCR. The overall accuracy rate was 69% (156/225), sensitivity 76% (113/148), specificity 56% (43/77), positive predictive value 77% (113/147), and negative predictive value 55% (43/78). The PPV was significantly associated with receptor status (p = 0.004). No patient or imaging characteristics were associated with sensitivity. CONCLUSION: Breast MRI only moderately predicts pathologic response for invasive breast cancer treated with NAC (overall accuracy 69%). PPV is significantly associated with receptor status.

Synchronous and metachronous thyroid cancer, breast cancer, and melanoma in a premenopausal patient with Cowden syndrome.

Cowden syndrome is a rare autosomal dominant genetic disorder characterized by a germline mutation in the phosphatase and tensin homolog gene, leading to multiple hamartomas, neurodevelopmental disorders, and an increased lifetime risk of multiple cancers. Malignancy is the most common cause of mortality in Cowden syndrome, with breast cancer being the most common malignancy encountered in females with the disorder. Screening guidelines for this population should address this risk at an early age. We present a case of metachronous thyroid cancer followed by synchronous breast cancer and melanoma in a young female with Cowden syndrome, highlighting diagnostic imaging, management, and screening considerations.

Solitary Dilated Ducts Revisited: Malignancy Rate and Implications for Management.

RATIONALE AND OBJECTIVES: A solitary dilated duct (SDD) is a single asymmetrically dilated breast duct with diameter more than 2 mm. The Breast Imaging Reporting and Data System (BI-RADS) fifth edition recommends additional imaging and biopsy for SDDs without demonstrated benign etiology, however management of this rare entity remains controversial. This study describes practice patterns, malignancy rate, and features associated with high-risk/malignant SDDs to better stratify patients requiring biopsy versus follow-up. MATERIALS AND METHODS: This IRB-approved retrospective study identified mammographic, sonographic and MRI exams utilizing the term "solitary dilated duct" at a multisite academic institution between 1/1/2010 and 12/31/2020. Clinical and imaging features, BI-RADS assessments, and outcomes were analyzed. Univariate and multivariate analyses identified predictors of high-risk/malignant histology. RESULTS: SDDs identified in 49 women (mean age 56.1 years) were assessed as BI-RADS 4/5 (31/49, 63%), BI-RADS 3 (9/49, 18%), or BI-RADS 2 (9/49, 18%). Most sampled lesions were benign (16/31, 52%) and the remaining were high-risk (15/31, 48%, all papillary lesions). The only papilloma with atypia on core biopsy upgraded to grade 2 DCIS on excision (malignancy rate 1/49, 2%). All anechoic SDDs were benign (n=13), and all benign SDDs lacked internal vascularity. SDDs with associated masses were associated with malignant/high-risk outcomes on multivariate analysis (p < .001). CONCLUSION: The BI-RADS fifth edition recommends biopsy for SDDs without demonstrated benign etiology. In our 11-year study period, practice patterns were variable with a low malignancy rate of 2%. Our findings suggest that anechoic SDDs may be followed, and SDDs with associated masses or internal vascularity require biopsy.

Circumscribed Masses on Breast MRI: Can MRI Features Guide Management?

OBJECTIVE: Management of circumscribed breast masses seen on MRI is largely extrapolated from mammography and US data with limited MRI-specific data available. This study aimed to assess clinical and MRI imaging features of malignant circumscribed breast masses. METHODS: In this IRB-approved retrospective study, breast MRIs performed between April 1, 2008, and August 30, 2020, containing circumscribed masses, excluding multiple bilateral circumscribed masses, were reviewed. Clinical and imaging features of all eligible masses were recorded, and associations with malignant outcomes were assessed using Fisher's exact test and Wilcoxon rank sum test, with P < 0.05 considered significant. RESULTS: For the 165 masses that met study criteria in 158 women, the mean age was 48 years (SD 12.0 years). Nine of 165 masses were malignant (5.5%). Round masses were significantly more likely to be malignant (7/37, 18.9%) compared to oval masses (2/128, 1.7%) (P < 0.001). Among masses with available dynamic contrast kinetics data, the malignancy rate was 0/84 (0%) for persistent kinetics, 2/23 (8.7%) for plateau kinetics, and 4/24 (16.7%) for washout kinetics (P = 0.002). The malignancy rate for oval masses without washout kinetics was 0% (0/92). T2 hyperintense masses had a malignancy rate of 7/104 (6.7%), and homogeneously enhancing masses had a malignancy rate of 5/91 (5.5%). CONCLUSION: These data support the use of mass shape and dynamic contrast enhancement kinetics to guide management of circumscribed breast masses seen by MRI, with oval masses without washout kinetics and any circumscribed mass with persistent kinetics showing no malignancies in this study.

BI-RADS 3 Assessment on MRI: A Lesion-Based Review for Breast Radiologists.

Unlike mammography and US, limited data exist to establish well-defined criteria for MRI findings that have a ≤2% likelihood of malignancy. Therefore, determining which findings are appropriate for a BI-RADS 3 assessment on MRI remains challenging and variable among breast radiologists. Emerging data suggest that BI-RADS 3 should be limited to baseline MRI examinations (or examinations with less than two years of prior comparisons) performed for high-risk screening and only used for masses with all of the typical morphological and kinetic features suggestive of a fibroadenoma or dominant enhancing T2 hypointense foci that is distinct from background parenchymal enhancement and without suspicious kinetics. This article presents an updated discussion of BI-RADS 3 assessment (probably benign) for breast MRI using current evidence.

High-risk lesions in the breast diagnosed by MRI-guided core biopsy: upgrade rates and features associated with malignancy.

PURPOSE: This study assessed the upgrade rates of high-risk lesions (HRLs) in the breast diagnosed by MRI-guided core biopsy and evaluated imaging and clinical features associated with upgrade to malignancy. METHODS: This IRB-approved, retrospective study included MRI-guided breast biopsy exams yielding HRLs from August 1, 2011, to August 31, 2020. HRLs included atypical ductal hyperplasia (ADH), lobular carcinoma in situ (LCIS), atypical lobular hyperplasia (ALH), radial scar, and papilloma. Only lesions that underwent excision or at least 2 years of MRI imaging follow-up were included. For each HRL, patient history, imaging features, and outcomes were recorded. RESULTS: Seventy-two lesions in 65 patients were included in the study, with 8/72 (11.1%) of the lesions upgraded to malignancy. Upgrade rates were 16.7% (2/12) for ADH, 100% (1/1) for pleomorphic LCIS, 40% (2/5) for other LCIS, 0% (0/19) for ALH, 0% (0/18) for papilloma, and 0% (0/7) for radial scar/complex sclerosing lesion. Additionally, two cases of marked ADH bordering on DCIS and one case of marked ALH bordering on LCIS, were upgraded. Lesions were more likely to be upgraded if they presented as T2 hypointense (versus isotense, OR 6.46, 95% CI 1.27-32.92) or as linear or segmental non-mass enhancement (NME, versus focal or regional, p = 0.008). CONCLUSION: Our data support the recommendation that ADH and LCIS on MRI-guided biopsy warrant surgical excision due to high upgrade rates. HRLs that present as T2 hypointense, or as linear or segmental NME, should be viewed with suspicion as these were associated with higher upgrade rates to malignancy.

Disparities Associated With Patient Adherence to BI-RADS 3 Assessment Follow-up Recommendations for Mammography and Ultrasound.

OBJECTIVE: To assess the relationship between sociodemographic factors and adherence rates in patients with a BI-RADS 3 assessment. METHODS: This retrospective cohort study reviewed data from all patients with a BI-RADS 3 assessment on mammography and ultrasound examinations at a single, multisite academic institution, which serves a diverse urban-suburban population, from January 1, 2015, to December 13, 2017. Appropriate follow-up was defined as returning for the first follow-up examination 3 to 9 months after the index examination. Associations between BI-RADS 3 adherence rates and patient sociodemographic characteristics were evaluated using logistic regression. RESULTS: There were 4,038 patients in our study period; 2,437 patients (60%) had appropriate follow-up, 765 (19%) patients had delayed follow-up, and 836 patients (21%) were lost to follow-up. The overall malignancy rate was 1.4% (46 of 3,202). Older age, retired employment status, and Medicare insurance status were associated with increased adherence to BI-RADS 3 follow-up recommendations. Black race, single relationship status, Medicaid and self-pay insurance status, and living in a top 15% disadvantaged zip code were associated with decreased adherence. On multivariate analysis, older age remained associated with increased adherence and Medicaid insurance status with decreased adherence. Time between index examination and cancer diagnosis was shorter in patients who had timely follow-up (202 days [interquartile range 183-358] versus 392 days [interquartile range 365-563], P ≤ .001), although there was not a significant difference in stage at diagnosis (P = .46). DISCUSSION: Multiple sociodemographic factors are associated with low adherence to BI-RADS 3 follow-up recommendations suggesting that more frequent and targeted interventions are needed to close disparity gaps.

Outcomes of Canceled Tomosynthesis-Guided Biopsy of Architectural Distortion Due to Nonvisualization.

Objective: Architectural distortion without a sonographic correlate is an indication for digital breast tomosynthesis-guided vacuum-assisted biopsy (DBT-VAB). However, when the finding is not visualized on the day of biopsy, the procedure is canceled. This study reports the outcomes of canceled DBT-VAB of architectural distortion due to nonvisualization. Methods: In this IRB-approved retrospective study, chart review was performed to identify DBT-VABs of architectural distortion at our institution between June 1, 2017, and November 1, 2020, that were canceled because of nonvisualization at the time of biopsy. Cases without follow-up imaging were excluded. Statistical analysis, including the frequency of cases yielding malignancy by the end of the study period, was performed. Results: In total, 7.2% (39/544) of architectural distortions recommended for biopsy during the study period were canceled because of nonvisualization, 30 of which had follow-up imaging and were included in the study. Mean patient age was 56 years (standard deviation [SD], 9.6 years) and mean follow-up time was 26.7 months (SD, 11.2 months; range, 8.4-50.9 months). During the follow-up period, 16.7% (5/30) underwent repeat biopsy attempt, with one malignant result (1/30, 3.3%; SD, 18%; 95% confidence interval: 0.6%-16.7%). In total, 86.7% (26/30) of cases were declared benign during the follow-up period and 10% (3/30) remained stable with a BI-RADS 3 assessment category. Conclusion: During available follow-up, there was a low likelihood that distortions not visualized at the time of DBT-VAB represented malignancy (3.3%, 1/30). While this low malignancy rate is reassuring, imaging follow-up is warranted.

Artificial Intelligence for Reducing Workload in Breast Cancer Screening with Digital Breast Tomosynthesis.

Background Digital breast tomosynthesis (DBT) has higher diagnostic accuracy than digital mammography, but interpretation time is substantially longer. Artificial intelligence (AI) could improve reading efficiency. Purpose To evaluate the use of AI to reduce workload by filtering out normal DBT screens. Materials and Methods The retrospective study included 13 306 DBT examinations from 9919 women performed between June 2013 and November 2018 from two health care networks. The cohort was split into training, validation, and test sets (3948, 1661, and 4310 women, respectively). A workflow was simulated in which the AI model classified cancer-free examinations that could be dismissed from the screening worklist and used the original radiologists' interpretations on the rest of the worklist examinations. The AI system was also evaluated with a reader study of five breast radiologists reading the DBT mammograms of 205 women. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and recall rate were evaluated in both studies. Statistics were computed across 10 000 bootstrap samples to assess 95% CIs, noninferiority, and superiority tests. Results The model was tested on 4310 screened women (mean age, 60 years ± 11 [standard deviation]; 5182 DBT examinations). Compared with the radiologists' performance (417 of 459 detected cancers [90.8%], 477 recalls in 5182 examinations [9.2%]), the use of AI to automatically filter out cases would result in 39.6% less workload, noninferior sensitivity (413 of 459 detected cancers; 90.0%; P = .002), and 25% lower recall rate (358 recalls in 5182 examinations; 6.9%; P = .002). In the reader study, AUC was higher in the standalone AI compared with the mean reader (0.84 vs 0.81; P = .002). Conclusion The artificial intelligence model was able to identify normal digital breast tomosynthesis screening examinations, which decreased the number of examinations that required radiologist interpretation in a simulated clinical workflow. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Philpotts in this issue.

COVID-19 Vaccine-Related Axillary Adenopathy on Breast Imaging: Follow-Up Recommendations and Histopathologic Findings.

This study describes 94 patients who presented with suspected COVID-19 vaccine-related axillary adenopathy on breast imaging. All biopsies recommended within 12 weeks of the second vaccine dose were benign. Among women not recommended for biopsy, the median interval between the second vaccine dose and ultrasound follow-up was 15.9 weeks. Three biopsies yielding malignant diagnoses were recommended 12.0-13.1 weeks after the second vaccine dose. Lengthening imaging follow-up to 12-16 weeks after the second dose may reduce unnecessary biopsy recommendations.

Developing Asymmetries without Sonographic Correlate at Digital Breast Tomosynthesis.

Background Digital breast tomosynthesis (DBT) has improved the accuracy of mammography, including resolving many breast asymmetries as overlapping breast tissue. The pathologic outcomes of persistent developing asymmetries visualized at DBT are not well established. Purpose To characterize the outcomes and the predictors of malignancy for developing asymmetries visualized at DBT without a sonographic correlate. Materials and Methods This retrospective study included all tomosynthesis-guided biopsies of developing asymmetries performed at a single institution from May 2017 through January 2020. A reader study including three breast imaging radiologists determined interrater agreement and inclusion into the study. Electronic medical records were used to extract patient characteristics, imaging characteristics, and pathologic diagnoses. The Wilcoxon rank sum test, Fisher exact test, and χ2 test were used to analyze correlations of patient and imaging characteristics with likelihood of malignancy. Results The reader study included 95 DBT examinations with moderate interrater reliability (Fleiss κ = 0.45). There was majority reader agreement in 85 of the 95 DBT examinations (89%) of 83 women (median age, 56 years; interquartile range, 47-69 years), and this finalized the study data set. At pathologic examination, most asymmetries (68 of 85, 80%) were benign, with common diagnoses being fibrocystic change (n = 20), stromal fibrosis (n = 10), and fat necrosis (n = 10). The overall malignancy rate was 20% (17 of 85 asymmetries; 95% CI: 12, 29); 15 of the 17 malignancies (88%) were invasive cancers. Malignancies were more common in women with a personal history of breast cancer (35% vs 10%, P = .02). Conclusion In 85 developing asymmetries visualized at digital breast tomosynthesis without a sonographic correlate, there was a 20% (95% CI: 12, 29) malignancy rate, which was higher than the rates of malignancy for a developing asymmetry detected at digital mammography. © RSNA, 2021 See also the editorial by Skaane in this issue.

Disparities Associated With Patient Adherence of Post-Breast-Conserving Surgery Surveillance Imaging Protocols.

OBJECTIVE: Currently, national and international breast imaging practices utilize variable postsurgical surveillance protocols without uniform recommendations. Because of the innate differences between screening versus diagnostic mammography from scheduling flexibility to out-of-pocket costs, this creates the opportunity for lapses in patient adherence, which has the potential to impact clinical outcomes. The purpose of this study is to evaluate the relationship between sociodemographic factors and postsurgical surveillance imaging protocols on patient adherence rates. METHODS: This retrospective study reviewed 3 years of surveillance imaging for all patients having breast-conserving surgery at our institution from January 2011 to December 2016. Follow-up adherence was defined as returning for all of the first 3 years of annual follow-up after breast-conserving surgery (institutional surveillance protocol). Associations between adherence to surveillance imaging and patient sociodemographic characteristics were evaluated using univariate and multivariate logistic regression. RESULTS: The study included 1,082 patients after breast surgery, 715 of whom adhered completely to the first 3 years of annual follow-up (66.1%). Black women were 1.36 times less likely to follow up annually compared with White women (95% confidence interval 1.02-1.80). Similarly, patients with Medicare were 1.84 times less likely to follow up annually compared with patients with private insurance (95% confidence interval 1.34-2.51). Women with benign breast disease after breast-conserving surgery were significantly less likely to adhere to annual surveillance than women with breast cancer. CONCLUSION: Sociodemographic disparities exist as barriers for annual mammography surveillance in patients after breast-conserving surgery.

Diagnostic Versus Screening Mammography Recommendations for Postlumpectomy Imaging Surveillance of Patients With Breast Cancer.

Among 707 women who were recommended to undergo annual diagnostic mammography (DM) surveillance after lumpectomy for breast cancer, 94.9%, 90.4%, and 84.3% of women presented for DM at years 1, 2, and 3 after lumpectomy. A total of 18.8%, 11.0%, and 9.9% of women received additional views at years 1, 2, and 3, compared with the 10.1% institutional screening recall rate. The postlumpectomy year 3 cancer detection rate of 11.7 cancers per 1000 DM examinations was below DM benchmarks. These preliminary findings suggest that returning to screening mammography may be acceptable after 1 year of postlumpectomy DM follow-up.

Tomosynthesis-Guided Vacuum-Assisted Breast Biopsy of Architectural Distortion Without a Sonographic Correlate: A Retrospective Review.

BACKGROUND. Digital breast tomosynthesis-guided vacuum-assisted breast biopsy (DBT VAB) allows biopsy of findings seen better or exclusively on digital breast tomosynthesis (DBT), including architectural distortion. Although architectural distortion with an associated sonographic mass correlate has a high risk of malignancy, limited data describe the radiologic-pathologic correlation of tomosynthesis-detected architectural distortion without a sonographic correlate. OBJECTIVE. This study evaluates the malignancy rate of architectural distortions without a sonographic correlate that undergo DBT VAB and provides radiologic-pathologic correlation for benign, high-risk, and malignant entities that are associated with architectural distortion. METHODS. We retrospectively reviewed imaging, as well as pathology slides and/or reports, for DBT VABs performed for architectural distortion without a sonographic correlate at a single institution between June 1, 2017, and January 15, 2020. According to the correlative histopathology, cases were categorized as benign, high risk, or malignant, and specific histopathologic diagnoses were summarized. RESULTS. During the study period, 142 patients (mean age, 59 years) underwent DBT VAB for 151 unique architectural distortions without a sonographic correlate. DBT VAB revealed a malignant diagnosis in 27 (18%), a high-risk lesion in 50 (33%), and a benign diagnosis in 74 (49%). Two cases of atypical ductal hyperplasia were upgraded to malignancy, resulting in a final malignancy rate of 19% (n = 29/151). Most malignant lesions were invasive carcinomas (83%, n = 24/29); most invasive carcinomas were of lobular subtype (54%, n = 13/24). Most high-risk lesions were radial scars/complex sclerosing lesions (62%, n = 31/50). Most benign results represented fibrocystic change (66%, n = 49/74). A subset (11%, n = 8/74) of benign results were considered discordant and subsequently excised, with none representing malignancy. CONCLUSION. The final malignancy rate of 19% in architectural distortion without a sonographic correlate justifies a recommendation for biopsy using DBT VAB. CLINICAL IMPACT. Our results highlight the utility of DBT VAB in the era of DBT. The detailed radiologic-pathologic correlations will assist radiologists in assessing concordance when performing DBT VAB for architectural distortions and provide a reference for future patient management.

Rare case of invasive lobular carcinoma in a male.

Invasive lobular carcinoma (ILC) in the male breast is a rare subtype of a rare disease in men, accounting for approximately 1%-2% of all male breast cancers [1,2]. Only a few cases have been reported in the literature. The pathophysiology is uncommon due to a paucity of lobular development seen in men. We present a rare case of ILC in the male breast, highlighting imaging, pathology findings, and clinical management.