Imaging Surveillance Options for Individuals With a Personal History of Breast Cancer: AJR Expert Panel Narrative Review.

Annual surveillance mammography is recommended for breast cancer survivors on the basis of observational studies and meta-analyses showing reduced breast cancer mortality and improved quality of life. However, breast cancer survivors are at higher risk of subsequent breast cancer and have a fourfold increased risk of interval breast cancers compared with individuals without a personal history of breast cancer. Supplemental surveillance modalities offer increased cancer detection compared with mammography alone, but utilization is variable, and benefits must be balanced with possible harms of false-positive findings. In this review, we describe the current state of mammographic surveillance, summarize evidence for supplemental surveillance in breast cancer survivors, and explore a risk-based approach to selecting surveillance imaging strategies. Further research identifying predictors associated with increased risk of interval second breast cancers and development of validated risk prediction tools may help physicians and patients weigh the benefits and harms of surveillance breast imaging and decide on a personalized approach to surveillance for improved breast cancer outcomes.

Analysis of 612 Benign Papillomas Diagnosed at Core Biopsy: Rate of Upgrade to Malignancy, Factors Associated With Upgrade, and a Proposal for Selective Surgical Excision.

BACKGROUND. Despite numerous published studies, management of benign papillomas without atypia remains controversial. OBJECTIVE. The purpose of this study was to determine the malignancy upgrade rate of benign papillomas, identify risk factors for upgrade, and formulate criteria for selective surgery. METHODS. This retrospective study included benign papillomas without atypia diagnosed on percutaneous biopsy between December 1, 2000, and December 31, 2019. Papillomas that did not undergo surgical excision or at least 2 years of imaging and/or clinical follow-up were excluded. Clinical, imaging, and histopathologic features were extracted from the electronic medical record. Features associated with upgrade to malignancy were identified. Multivariable logistic regression was performed. RESULTS. The study included 612 benign papillomas in 543 women (mean age, 54.5 ± 12.1 [SD] years); 466 papillomas were excised, and 146 underwent imaging or clinical surveillance. The upgrade rate to malignancy was 2.3% (14/612). Upgrade rate was associated (p < .05) with radiology-pathology correlation (50.0% if discordant vs 2.1% if concordant), patient age (5.6% for 60 years and older vs 0.7% for younger than 60 years), presenting symptoms (6.7% if palpable mass or pathologic nipple discharge vs 1.3% if no symptoms), and lesion size (7.3% if ≥ 10 mm vs 0.6% if < 10 mm). Three of 14 upgraded papillomas were associated with four or more metachronous or concurrent peripheral papillomas. No incidental papilloma or papilloma reported as completely excised on core biopsy histopathologic analysis was upgraded. A predictive model combining radiology-pathology discordance, symptoms (palpable mass or nipple discharge), age 60 years old and older, size 10 mm or larger, and presence of four or more metachronous or concurrent peripheral papillomas achieved an AUC of 0.91, sensitivity of 79%, and spec-ificity of 89% for upgrade. Selective surgery based on presence of any of these five factors, although excluding from surgery incidental papillomas and papillomas reported as completely excised on histopathology, would have spared 294 of 612 lesions from routine excision and identified all 14 upgraded lesions. CONCLUSION. Benign nonatypical papillomas have a low malignancy upgrade rate; routine surgical excision may not be necessary. Selective excision is recommended for lesions satisfying any of the five criteria. Incidental papillomas or papillomas completely excised on histopathology may undergo imaging follow-up. CLINICAL IMPACT. The proposed criteria for selective surgery of benign papillomas on core biopsy would reduce surgeries without delaying diagnosis of malignancy.

Asymmetric Ductal Ectasia: An Often Overlooked Sign of Malignancy.

OBJECTIVE. The objective of this article is to define the clinical significance of asymmetric ductal ectasia by a review of literature and to describe the imaging findings. CONCLUSION. Asymmetric ductal ectasia has a significant risk for malignancy and high-risk lesions. The findings on conventional imaging may be subtle and easily overlooked. Asymmetric ductal ectasia should be included in the search pattern during image interpretation. Tissue sampling is usually warranted. Ultrasound is critical in identifying ductal abnormalities to guide biopsy.

The Management of Benign Concordant MRI-guided Brest Biopsies: Lessons Learned.

After benign concordant magnetic resonance imaging (MRI)-guided breast biopsy, initial follow-up MRI at 6 months is often recommended for confirmation. This study was undertaken to determine the proper management of stable lesions on initial follow-up MRI and whether such follow-up can be safely deferred to 12 months. Retrospective review of 240 MRI-guided biopsies identified 156 benign concordant lesions. 85 eligible cases received follow-up MRI and constitute the study population. On initial follow-up MRI, 72 of 85 lesions appeared adequately sampled, 12 were stable and underwent further MRI follow-up, and 1 was benign on subsequent surgery. No cancers were diagnosed at the biopsy sites on either 6- or 12-month follow-up MRI. Among the 12 stable lesions, four were masses and eight were nonmass enhancements. One of the stable masses enlarged on 24-month follow-up MRI and proved malignant. All stable nonmass lesions were benign on long-term follow-up. After benign concordant MRI-guided breast biopsy, a stable mass has a 25% probability of malignancy in our series. Re-biopsy of such masses should be strongly considered. Stable nonmass lesions may be followed with subsequent MRI without rebiopsy. Deferral of initial follow-up MRI to 12 months may be acceptable.

Exploiting the advantages of a wireless seed localization system that differentiates between the seeds: Breast cancer resection following neoadjuvant chemotherapy.

BACKGROUND: Most wireless localization methods utilize only one means of detection for the surgeon, sufficient to localize a single small breast lesion for excision. Complex cases requiring bracketing of a larger lesion or localization of two or more close lesions can superimpose the signal from separate "seeds" with such methods. The lack of discernment between the localization "seeds" can disorient the surgeon, risking a missed lesion on excision and longer operative times. with the use of neoadjuvant chemotherapy prior to breast surgery, the necessity of localizing both a breast lesion and an axillary lymph node previously biopsied is becoming frequent. CASE: A 44 year-old woman underwent neoadjuvant chmotherapy for a breast cancer the did not express estrogen receptor, progesterone receptor, or HER2 receptor. In establishing the extent of disease, a suspicious ipsilateral lymph node was biopsied and found to contain metastatic disease. She had an excellent response to the chemotherapy, with decreased size of the primary tumor and the previously biopsied lymph node. The patient desired breast conservation. The primary tumor and associated calcifications were bracketed using two different Smartclips™, with a third localizing the lymph node biopsied. CONCLUSION: This report illustrates how the use of three SmartClips™, within the EnVisioTM system, allowed for separate tracking of each "seed" throughout a complex surgery in a patient following neoadjuvant chemotherapy. This resulted in successful resection of both the tumor and the tagged lymph node.

MRI features of stromal fibrosis of the breast with histopathologic correlation.

OBJECTIVE: The purpose of this article is to present the MRI features of stromal fibrosis of the breast, thus enabling radiologists to better determine radiologic-pathologic concordance of biopsy results and appropriate patient management. MATERIALS AND METHODS: A retrospective review of radiology records between 2003 and 2009 identified 123 MRI-detected lesions with the histologic diagnosis of stromal fibrosis. Of these, 83 cases were excluded either because stromal fibrosis was not the primary histologic diagnosis, or because there were associated pathologic abnormalities that may have contributed to contrast enhancement. The remaining 40 lesions with a primary histologic diagnosis of stromal fibrosis were included in our study. Their MRI and histopathologic features were examined and categorized. RESULTS: The lesions included five foci, 23 masses, and 12 areas of nonmasslike enhancements. The prevalent features of the masses were size smaller than 1 cm (20/23 [87%]), round or oval shape (16/23 [70%]), irregular or spiculated margins (15/23 [65%]), rapid or medium rate of initial contrast uptake (21/23 [91%]), and plateau or washout curves (16/23 [70%]). Most nonmass lesions showed clumped enhancement (9/12) and linear distribution (7/12). Many of these features were suggestive of malignancy. Twenty-seven of 40 cases (68%) had histologic confirmation by excision or MRI confirmation of benignancy. No false-negative cases have been identified to date. Histopathologic correlation showed the presence of masslike septal fibrosis associated with ectatic vascular channels in 60-67% of cases, which may lead to increased contrast enhancement on MRI. CONCLUSION: Stromal fibrosis has widely variable MRI features, often mimicking breast carcinoma. It may represent an acceptable benign concordant diagnosis on vacuum-assisted large-core needle biopsy for the described MRI findings.

Upgrade Rate of Pure Flat Epithelial Atypia Diagnosed at Core Needle Biopsy: A Systematic Review and Meta-Analysis.

Purpose: To perform a systematic review and meta-analysis to calculate the pooled upgrade rate of pure flat epithelial atypia (FEA) diagnosed at core needle biopsy (CNB). Materials and Methods: A PubMed and Embase database search was performed in December 2019. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Study quality and publication bias were assessed. The upgrade rate of pure FEA to cancer, invasive carcinoma, and ductal carcinoma in situ (DCIS), as well as the co-occurrence rate of atypical ductal hyperplasia (ADH), with 95% CIs were calculated. A random effect model was used to integrate the proportions and their corresponding 95% CI. Study heterogeneity was calculated using τ2 and I 2 . Results: A total of 2482 cases of pure FEA across 42 studies (mean age range, 46-59 years) met inclusion criteria to be analyzed. Significant study heterogeneity was identified (τ2 = 0.001, I 2 = 67%). The pooled upgrade rates reported for pure FEA were 5% (95% CI: 3%, 6%) for breast cancer, 1% (95% CI: 0%, 2%) for invasive carcinoma, and 2% (95% CI: 1%, 3%) for DCIS. When more than 90% of calcifications were removed at CNB, the pooled upgrade rate was 0% (95% CI: 0%, 2%). The pooled co-occurrence rate of ADH at surgical excision was 17% (95% CI: 12%, 21%). Study quality was medium to high with a risk of publication bias (P < .01). Conclusion: Pure FEA diagnosed at CNB should be surgically excised due to the pooled upgrade rate of 5% for breast cancer. If more than 90% of the targeted calcifications are removed by CNB for pure FEA, close imaging follow-up is recommended.Keywords: Biopsy/Needle Aspiration, Breast, MammographySupplemental material is available for this article.© RSNA, 2021.

Screening Mammogram Results in the Digital Age: Video Messaging - A Pilot Study.

OBJECTIVE: To assess patients' preferences for receiving screening mammogram results via a video message from their radiologist versus the traditional methods. METHODS: The Institutional Review Board approved this prospective study which enrolled participants from March to May 2019, after written consent was obtained. Two breast radiologists prerecorded video results for normal and abnormal screening mammograms. Women 40 years and older presenting for a screening mammogram who had a prior mammogram and no clinical symptoms were invited to participate in the study. After their mammogram, participants were assigned to obtain results via video message or by traditional methods such as a mailed letter or phone call. Participants then completed an online survey asking questions regarding the method of results delivery. RESULTS: Around 80/94 participants ranging in age from 40 to 76 years old responded (85% response rate), of which 73% (58/80) preferred a video message from the radiologist for their mammogram results (p = 0.029). When analyzed by age, the video results were most liked by patients 40-60 years old. When analyzed by education level, participants with a Master's or Bachelor's degree liked receiving their results by video. DISCUSSION: Our study suggests that patients in the screening mammography setting may prefer a video message from their radiologist to the traditional methods of delivery, including mailed letters and receiving results from their primary care provider. Video results could potentially be utilized in the delivery of other results of standardized medical tests as a method to offer more timely delivery of results and a personal connection.

Characterization of common breast MRI abnormalities: comparison between abbreviated and full MRI protocols.

RATIONALE AND OBJECTIVES: To evaluate the diagnostic performance of abbreviated MRI (AB-MRI) in comparison to a full protocol MRI (FP-MRI) when evaluating common MRI abnormalities of a mass, non-mass enhancement and focus. MATERIALS AND METHODS: This retrospective reader study was Institutional Review Board approved and Health Insurance Portability and Accountability Act (HIPAA) compliant. AB-MRIs were reviewed from May 2018-December 2019 to identify women with an abnormal AB-MRI, FP-MRI within six months of the AB-MRI and an elevated risk for breast cancer. Six breast radiologists initially interpreted and recorded findings from the AB-MRI. Immediately after reviewing the AB-MRI, the same radiologists interpreted and recorded findings from the FP-MRI. Findings were recorded in an electronic data collection form. Cohen's Kappa test was used to calculate agreement. P < 0.05 was considered statistically significant. RESULTS: Of 119 patients who had an AB-MRI, our final study comprised of 32 patients who had 64 breast MRIs (32 AB-MRI and 32 FP-MRI). The amount of fibroglandular tissue for AB-MRI and FP-MRI showed excellent intra-reader agreement [Kappa: 0.89-1.00 (P < 0.0001)]. Substantial to excellent intra-reader agreement [Kappa: 0.74-0.93 (P < 0.0001)] was demonstrated for all 6 readers when identifying abnormalities seen on AB-MRI and FP-MRI. Moderate to excellent intra-reader agreement [Kappa: 0.41-0.87(P < 0.0001)] was demonstrated between the AB-MRI and FP-MRI for the final BI-RADS assessment. CONCLUSION: AB-MRI has acceptable intra-reader agreement with FP-MRI when characterizing common MRI abnormalities such as a mass, non-mass enhancement and focus suggesting that subsequent FP-MRI may not be needed.

MRI Evaluation of the Contralateral Breast in Women with Recently Diagnosed Breast Cancer: 2-Year Follow-up.

OBJECTIVE: The American College of Radiology Imaging Network Trial 6667 showed that MRI can detect cancer in the contralateral breast that is missed by mammography and clinical examination at the time of the initial breast cancer diagnosis, based on 1-year follow-up. This study is a continuation of the trial that evaluates the diagnostic accuracy of MRI for contralateral breast cancer after 2 years of follow-up. METHODS: In total, 969 women with a diagnosis of unilateral breast cancer and no clinical or imaging abnormalities in the contralateral breast underwent breast MRI. The cancer status of all participants was monitored for 2 years after the initial MRI. Follow-up included documentation of any clinical, imaging, or interventional procedures performed. A study participant was considered positive for cancer if she had a tissue diagnosis of in situ or invasive breast cancer in the contralateral breast within 730 days of her initial MRI. RESULTS: Three additional cancers were diagnosed in the study population in the second year of the trial. The diagnostic yield for MRI for the 2-year period was 3% (31/969). After 2 years of follow-up, breast MRI has a sensitivity of 86% and specificity of 88% for detection of contralateral breast cancer. Its negative predictive value was 99%, and its positive predictive value was 22%. These values did not change significantly from the 1-year data. CONCLUSION: A negative contralateral breast MRI has a very high and reliable negative predictive value over 2 years, and, therefore, is helpful in managing and counseling patients during the period of initial diagnosis and early treatment.

Textural Characteristics of Biopsy-proven Metastatic Axillary Nodes on Preoperative Breast MRI in Breast Cancer Patients: A Feasibility Study.

OBJECTIVE: To determine the diagnostic accuracy of MRI textural analysis (TA) to differentiate malignant from benign axillary lymph nodes in patients with breast cancer. METHODS: This was an institutional review board-approved retrospective study of axillary lymph nodes in women with breast cancer that underwent ultrasound-guided biopsy and contrast-enhanced (CE) breast MRI from January 2015 to December 2018. TA of axillary lymph nodes was performed on 3D dynamic CE T1-weighted fat-suppressed, 3D delayed CE T1-weighted fat-suppressed, and T2-weighted fat-suppressed MRI sequences. Quantitative parameters used to measure TA were compared with pathologic diagnoses. Areas under the curve (AUC) were calculated using receiver operating characteristic curve analysis to distinguish between malignant and benign lymph nodes. RESULTS: Twenty-three biopsy-proven malignant lymph nodes and 24 benign lymph nodes were analyzed. The delayed CE T1-weighted fat-suppressed sequence had the greatest ability to differentiate malignant from benign outcome at all spatial scaling factors, with the highest AUC (0.84-0.93), sensitivity (0.78 [18/23] to 0.87 [20/23]), and specificity (0.76 [18/24] to 0.88 [21/24]). Kurtosis on the 3D delayed CE T1-weighted fat-suppressed sequence was the most prominent TA parameter differentiating malignant from benign lymph nodes (P < 0.0001). CONCLUSION: This study suggests that MRI TA could be helpful in distinguishing malignant from benign axillary lymph nodes. Kurtosis has the greatest potential on 3D delayed CE T1-weighted fat-suppressed sequences to distinguish malignant and benign lymph nodes.

Dermatofibrosarcoma protuberans of the breast: imaging features and review of the literature.

OBJECTIVE: The objective of our study was to present the imaging features, including an MRI example, of dermatofibrosarcoma protuberans of the breast, an uncommon soft-tissue neoplasm of the breast, and review the literature. CONCLUSION: Dermatofibrosarcoma protuberans is an extremely rare malignancy of the breast, with few published reports. This is the largest collection of such cases in a single institution with analysis of the imaging features.

A comparison of full-field digital mammograms versus 2D synthesized mammograms for detection of microcalcifications on screening.

OBJECTIVES: To compare the observer agreement of microcalcification detection on synthetic 2D images to full field digital mammography (FFDM) at screening and determine if calcifications can be detected to the same degree and given the same BI-RADS assessment. MATERIAL AND METHODS: Two-experienced radiologists retrospectively reviewed synthetic 2D images and FFDM, in separate sessions, to detect microcalcifications and provide a BIRADS assessment. A third experienced breast radiologist reviewed the cases that were disagreed upon and gave a final assessment. Between March 2016-December 2016, 414 women obtained a screening mammogram with tomosynthesis and acquisition of FFDM. 71 cases had combined FFDM and tomosynthesis images, calcifications visible on FFDM or no calcifications present, which comprised the study group. Synthetic 2D images were constructed from the DBT images. During session 1, all synthetic 2D images for the 71 cases were reviewed. During session 2, all the FFDM images for the 71 cases were reviewed. Tomosynthesis images were not reviewed. The agreement of detection of calcifications and BIRADS assessment between radiologists for FFDM and synthetic 2D images were assessed using Cohen's kappa test. Fisher's exact test was used to detect the differences in calcification identification among various breast densities on FFDM and synthetic 2D images. RESULTS: For the detection of calcifications between synthetic 2D images and FFDM, there was moderate to substantial agreement (p-values < 0.0001) for the two radiologist. For the BIRADS assessments, the agreement between synthetic 2D imaging and FFDM was moderate (p-values < 0.0001). The inter-reader agreement for detection of calcifications was fair for using synthetic 2D and moderate for using FFDM (p-value < 0.0001). The final inter-reader agreement between FFDM and synthetic 2D images for the detection of calcifications was moderate (p-values < 0.0001) with the addition of the third reader. For the final BI-RADS assessment, there was moderate agreement between synthetic 2D imaging and FFDM (p-value < 0.0001). The two readers did not demonstrate a significant difference in the detection of microcalcifications for those who were dense or non-dense (p-value range 0.076-0.302). CONCLUSION: Radiologist interpreting synthetic 2D imaging and FFDM have similar frequency for detection of calcifications and BIRADS assessment. A synthetic 2D mammogram may be a sufficient replacement for FFDM at screening.

ACR Appropriateness Criteria® Stage I Breast Cancer: Initial Workup and Surveillance for Local Recurrence and Distant Metastases in Asymptomatic Women.

Women and health care professionals generally prefer intensive follow-up after a diagnosis of breast cancer. However, there are no survival differences between women who obtain intensive surveillance with imaging and laboratory studies compared with women who only undergo testing because of the development of symptoms or findings on clinical examinations. American Society of Clinical Oncology and National Comprehensive Cancer Network guidelines state that annual mammography is the only imaging examination that should be performed to detect a localized breast recurrence in asymptomatic patients; more imaging may be needed if the patient has locoregional symptoms (eg, palpable abnormality). Women with other risk factors that increase their lifetime risk for breast cancer may warrant evaluation with breast MRI. Furthermore, the quality of life is similar for women who undergo intensive surveillance compared with those who do not. There is little justification for imaging to detect or rule out metastasis in asymptomatic women with newly diagnosed stage I breast cancer. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Evaluation of Nipple Discharge.

Appropriate imaging evaluation of nipple discharge depends the nature of the discharge. Imaging is not indicated for women with physiologic nipple discharge. For evaluation of pathologic nipple discharge, multiple breast imaging modalities are rated for evidence-based appropriateness under various scenarios. For women age 40 or older, mammography or digital breast tomosynthesis (DBT) should be the initial examination. Ultrasound is usually added as a complementary examination, with some exceptions. For women age 30 to 39, either mammogram or ultrasound may be used as the initial examination on the basis of institutional preference. For women age 30 or younger, ultrasound should be the initial examination, with mammography/DBT added when ultrasound shows suspicious findings or if the patient is predisposed to developing breast cancer. For men age 25 or older, mammography/DBT should be performed initially, with ultrasound added as indicated, given the high incidence of breast cancer in men with pathologic nipple discharge. Although MRI and ductography are not usually appropriate as initial examinations, each may be useful when the initial standard imaging evaluation is negative. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Palpable Breast Masses.

Breast cancer is the most common female malignancy and the second leading cause of female cancer death in the United States. Although the majority of palpable breast lumps are benign, a new palpable breast mass is a common presenting sign of breast cancer. Any woman presenting with a palpable lesion should have a thorough clinical breast examination, but because many breast masses may not exhibit distinctive physical findings, imaging evaluation is necessary in almost all cases to characterize the palpable lesion. Recommended imaging options in the context of a palpable mass include diagnostic mammography and targeted-breast ultrasound and are dependent on patient age and degree of radiologic suspicion as detailed in the document Variants. There is little role for advanced technologies such as MRI, positron emission mammography, or molecular breast imaging in the evaluation of a palpable mass. When a suspicious finding is identified, biopsy is indicated. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Breast Pain.

Breast pain (or tenderness) is a common symptom, experienced by up to 80% of women at some point in their lives. Fortunately, it is rarely associated with breast cancer. However, breast pain remains a common cause of referral for diagnostic breast imaging evaluation. Appropriate workup depends on the nature and focality of the pain, as well as the age of the patient. Imaging evaluation is usually not indicated if the pain is cyclic or nonfocal. For focal, noncyclic pain, imaging may be appropriate, mainly for reassurance and to identify treatable causes. Ultrasound can be the initial examination used to evaluate women under 30 with focal, noncyclic breast pain; for women 30 and older, diagnostic mammography, digital breast tomosynthesis, and ultrasound may all serve as appropriate initial examinations. However, even in the setting of focal, noncyclic pain, cancer as an etiology is rare. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Monitoring Response to Neoadjuvant Systemic Therapy for Breast Cancer.

Patients with locally advanced invasive breast cancers are often treated with neoadjuvant chemotherapy prior to definitive surgical intervention. The primary aims of this approach are to: 1) reduce tumor burden thereby permitting breast conservation rather than mastectomy; 2) promptly treat possible metastatic disease, whether or not it is detectable on preoperative staging; and 3) potentially tailor future chemotherapeutic decisions by monitoring in-vivo tumor response. Accurate radiological assessment permits optimal management and planning in this population. However, assessment of tumor size and response to treatment can vary depending on the modality used, the measurement technique (such as single longest diameter, 3-D measurements, or calculated tumor volume), and varied response of different tumor subtypes to neoadjuvant chemotherapy (such as concentric shrinkage or tumor fragmentation). As discussed in further detail, digital mammography, digital breast tomosynthesis, US and MRI represent the key modalities with potential to help guide patient management. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.