Nonpalpable, probably benign lesions: role of follow-up mammography

The Impact of Mammographic, Radiologist, and Patient Factors on the Likelihood of Probably Benign (BI-RADS 3) Assessment at Diagnostic Mammography

OBJECTIVE

To evaluate the association of mammographic, radiologist, and patient factors on BI-RADS 3 assessment at diagnostic mammography in patients recalled from screening mammography.

METHODS

This Institutional Review Board-approved retrospective study of consecutive unique diagnostic mammography examinations in asymptomatic patients recalled from screening mammography March 5, 2014, to December 31, 2019, was conducted in a single large United States health care institution. Mammographic features (mass, calcification, distortion, asymmetry), breast density, prior examination, and BI-RADS assessment were extracted from reports by natural language processing. Patient age, race, and ethnicity were extracted from the electronic health record. Radiologist years in practice, recall rate, and number of interpreted diagnostic mammograms were calculated. A mixed effect logistic regression model evaluated factors associated with likelihood of BI-RADS 3 compared with other BI-RADS assessments.

RESULTS

A total of 12 080 diagnostic mammography examinations were performed during the study period, yielding 2010 (16.6%) BI-RADS 3 and 10 070 (83.4%) other BI-RADS assessments. Asymmetry (odds ratio [OR] = 6.49, P <.001) and calcification (OR = 5.59, P <.001) were associated with increased likelihood of BI-RADS 3 assessment; distortion (OR = 0.20, P <.001), dense breast parenchyma (OR = 0.82, P <.001), prior examination (OR = 0.63, P = .01), and increasing patient age (OR = 0.99, P <.001) were associated with decreased likelihood. Mass, patient race or ethnicity, and radiologist factors were not significantly associated with BI-RADS 3 assessment. Malignancy rate for BI-RADS 3 lesions was 1.6%.

CONCLUSION

Asymmetry and calcifications had an increased likelihood of BI-RADS 3 assessment at diagnostic evaluation with low likelihood of malignancy, while radiologist features had no association.

Frequency and Outcomes of BI-RADS Category 3 Assessments in Patients With a Personal History of Breast Cancer: Full-Field Digital Mammography Versus Digital Breast Tomosynthesis

BACKGROUND. Studies establishing the validity of BI-RADS category 3 excluded patients with personal history of breast cancer (PHBC). Use of category 3 in patients with PHBC may be impacted not only by this population's increased breast cancer risk, but also by adoption of digital breast tomosynthesis (DBT) over full-field digital mammography (FFDM). OBJECTIVE. The purpose of this article was to compare the frequency, outcomes, and additional characteristics of BI-RADS category 3 assessments between FFDM and DBT in patients with PHBC. METHODS. This retrospective study included 14,845 mammograms in 10,118 patients (mean age, 63 years) with PHBC who had undergone mastectomy and/or lumpectomy. Of these, 8422 examinations were performed by FFDM from October 2014 to September 2016, and 6423 examinations by FFDM with DBT from February 2017 to December 2018, after interval conversion of the center's mammography units. Information was extracted from the EHR and radiology reports. FFDM and DBT groups were compared in the entire sample and among index category 3 lesions (i.e., earliest category 3 assessment per lesion). RESULTS. The frequency of category 3 assessment was lower for DBT than FFDM (5.6% vs 6.4%; p = .05). DBT, compared with FFDM, showed a lower malignancy rate for category 3 lesions (1.8% vs 5.0%; p = .04), higher malignancy rate for category 4 lesions (32.0% vs 23.2%; p = .03), and no difference in malignancy rate for category 5 lesions (100.0% vs 75.0%; p = .24). Analysis of index category 3 lesions included 438 and 274 lesions for FFDM and DBT, respectively. For category 3 lesions, DBT, compared with FFDM, showed lower PPV3 (13.9% vs 36.1%; p = .02) and a more frequent mammographic finding of mass (33.2% vs 23.1%; p = .003). CONCLUSION. The malignancy rate for category 3 lesions in patients with PHBC was less than the accepted limit (2%) for DBT (1.8%), but not FFDM (5.0%). A lower malignancy rate for category 3 lesions but higher malignancy rate for category 4 lesions for DBT supports more appropriate application of category 3 assessment in patients with PHBC through use of DBT. CLINICAL IMPACT. These insights may help establish whether category 3 assessments in patients with PHBC are within benchmarks for early detection of second cancers and reduction of benign biopsies.

A Single-Center Audit of BI-RADS 3 Assessment Category Utilization in Mammography and Breast Ultrasound

Purpose: To evaluate outcomes of breast lesions assessed at our institution as probably benign (Breast Imaging Reporting and Data System [BI-RADS] category 3) with an expected malignancy rate of less than or equal to 2 %. Methods: Average-risk women with a BI-RADS 3 assessment following mammographic and/or ultrasound evaluation at our institution between January 1 and December 31, 2017 were included. Cancer yield was calculated within 90 days and at 6-month intervals up to 36 months. Results: Among 517 women (median age, 52 years; range, 13-89 years) with a BI-RADS 3 assessment, 349 (67.5 %) underwent biopsy or completed follow-up imaging up to 36 months. One hundred and 68 (32.5 %) were lost to follow-up. Thirty of 349 (8.6 %) had their imaging upgraded and underwent biopsy, yielding six cancers (cancer yield, 6 of 349 women [1.7 %]). Among 569 lesions assessed as BI-RADS 3, 92 (16.2 %) were characterized by morphologic features other than those validated as probably benign in prospective clinical studies. Fifty three of 517 women (10.3 %) had follow-up beyond 24 months, and 24 (4.6 %) had follow-up beyond 36 months. Conclusion: Overall utilization of the BI-RADS 3 assessment category at our institution is appropriate with a 1.7 % cancer yield. However, the rate of loss to follow-up, percentage of non-validated findings assessed as probably benign, and redundancy in follow-up protocols are too high, and warrant intervention. A patient handout explaining the BI-RADS 3 assessment category and automatic scheduling of follow-up studies have been implemented at our center to address loss to follow-up.

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.

Cancer yield and imaging features of probably benign calcifications at digital magnification view

OBJECTIVES

To investigate the malignancy rate of probably benign calcifications assessed by digital magnification view and imaging and clinical features associated with malignancy.

METHODS

This retrospective study included consecutive women with digital magnification views assessed as probably benign for calcifications without other associated mammographic findings from March 2009 to January 2014. Initial studies rendering a probably benign assessment were analyzed, with biopsy or 4-year imaging follow-up. Fisher's exact test and univariable logistic regression were performed. Cancer yields were calculated.

RESULTS

A total of 458 lesions in 422 patients were finally included. The overall cancer yield was 2.2% (10 of 458, invasive cancer [n = 4] and DCIS [n = 6]). Calcification distribution (OR = 23.80, p = .041), calcification morphology (OR = 10.84, p = .005), increased calcifications (OR = 29.40, p = .001), and having a concurrent newly diagnosed breast cancer or high-risk lesion (OR = 10.24, p = .001) were associated with malignancy. Cancer yields did not significantly differ between grouped punctate calcifications vs. calcifications with other features (1.2% [2 of 162] vs. 2.7% [8 of 296], p = .506). The cancer yield was 1.6% (7 of 437) in women without newly diagnosed breast cancer or high-risk lesions.

CONCLUSION

The cancer yield of probably benign calcifications assessed by digital magnification view was below the 2% threshold for grouped punctate calcifications and for women without newly diagnosed breast cancer or high-risk lesions. Calcification distribution, morphology, increase in calcifications, and the presence of newly diagnosed breast cancer/high-risk lesion were associated with malignancy.

KEY POINTS

• Among 458 probably benign calcifications assessed by digital magnification view, the overall cancer yield was 2.2% (10 of 458). • The cancer yield was below the 2% threshold for grouped punctate calcifications (1.2%, 2 of 162) and in women without newly diagnosed breast cancer or high-risk lesions (1.6%, 7 of 437). • Calcification distribution, morphology, increase in calcifications, and the presence of newly diagnosed breast cancer/high-risk lesion were associated with malignancy (all p < .05).

Cancer Yield Exceeds 2% for BI-RADS 3 Probably Benign Findings in Women Older Than 60 Years in the National Mammography Database

Background Breast Imaging Reporting and Data System (BI-RADS) category 3 (BR3) (probably benign) mammographic assessments are reserved for imaging findings known to have likelihood of malignancy of 2% or less. Purpose To determine the effect of age, finding type, and prior mammography on cancer yield for BR3 findings in the National Mammography Database (NMD). Materials and Methods This HIPAA-compliant retrospective cohort institutional review board-exempt study evaluated women recalled from screening mammography followed by BR3 assessment at diagnostic evaluation from January 2009 to March 2018 and from 471 NMD facilities. Only the first BR3 occurrence was included for women with biopsy or imaging follow-up of at least 2 years. Women with a history of breast cancer or who underwent biopsy at time of initial BR3 assessment were excluded. Women were stratified by age in 10-year intervals. Cancer yield was calculated for each age group, with (for presumed new findings) and without prior mammographic comparison, and by lesion type, where available. Linear regression with weighted-age binning was performed to assess for differences between groups; P < .05 was indicative of a significant difference. Results A total of 1 380 652 (18.2%) women were recalled after screening mammography, of whom 157 130 (11.4%) were given a BR3 assessment within 90 days after screening. Of these, 43 628 women (median age, 55 years; age range, 25-90 years) had adequate follow-up for analysis. Cancer yield increased with increasing age decile, ranging from 0.51% (six of 1167) in women aged 30-39 years to 4.63% (41 of 885) in women aged 80-90 years; cancer yield exceeded 2% at and after age 59.7 years for baseline findings and at and after age 53.6 years for presumed new findings, although there was no effect on stage distribution. Cancer yield for baseline BR3 masses was 10 of 2111 (0.47% [95% CI: 0.24, 0.90]) versus 47 of 3003 (1.57% [95% CI: 1.16, 2.09]) with prior comparisons (P < .001); cancer yield for baseline calcifications was eight of 929 (0.86% [95% CI: 0.40, 1.76]) versus 84 of 2999 (2.80% [95% CI: 2.23, 3.47]) with prior comparisons (P < .001). Difference in cancer yield was 0.51% (95% CI: 0.16, 0.86) between women with and women without prior comparison at the same age (P = .006). Conclusion Cancer yield exceeded the 2% threshold for women aged 60 years or older and reached 4.6% for women aged 80-89 years. Breast Imaging Reporting and Data System 3 findings in women with a prior comparison had higher cancer yield than in those without a prior comparison at the same age. © RSNA, 2021 Online supplemental material is available for this article.

Follow-Up Intervals for Breast Imaging Reporting and Data System Category 3 Lesions on Screening Ultrasound in Screening and Tertiary Referral Centers

Objective

To assess the appropriate follow-up interval, and rate and timepoint of cancer detection in women with Breast Imaging Reporting and Data System (BI-RADS) 3 lesions on screening ultrasonography (US) according to the type of institution.

Materials and Methods

A total of 1451 asymptomatic women who had negative or benign findings on screening mammogram, BI-RADS 3 assessment on screening US, and at least 6 months of follow-up were included. The median follow-up interval was 30.8 months (range, 6.8–52.9 months). The cancer detection rate, cancer detection timepoint, risk factors, and clinicopathological characteristics were compared between the screening and tertiary centers. Nominal variables were compared using the chi-square or Fisher's exact test and continuous variables were compared using the independent t test or Mann-Whitney U test.

Results

In 1451 women, 19 cancers (1.3%) were detected; two (0.1%) were diagnosed at 6 months and 17 (1.2%) were diagnosed after 12.3 months. The malignancy rates were both 1.3% in the screening (9 of 699) and tertiary (10 of 752) centers. In the screening center, all nine cancers were invasive cancers and diagnosed after 12.3 months. In the tertiary center, two were ductal carcinomas in situ and eight were invasive cancers. Two of the invasive cancers were diagnosed at 6 months and the remaining eight cancers newly developed after 13.1 months.

Conclusion

One-year follow-up rather than 6-month follow-up may be suitable for BI-RADS 3 lesions on screening US found in screening centers. However, more caution is needed regarding similar findings in tertiary centers where 6-month follow-up may be more appropriate.

Rethinking prostate cancer screening: could MRI be an alternative screening test?

In the past decade rigorous debate has taken place about population-based screening for prostate cancer. Although screening by serum PSA levels can reduce prostate cancer-specific mortality, it is unclear whether the benefits outweigh the risks of false-positive results and overdiagnosis of insignificant prostate cancer, and it is not recommended for population-based screening. MRI screening for prostate cancer has the potential to be analogous to mammography for breast cancer or low-dose CT for lung cancer. A number of potential barriers and technical challenges need to be overcome in order to implement such a programme. We discuss different approaches to MRI screening that could address these challenges, including abbreviated MRI protocols, targeted MRI screening, longer rescreening intervals and a multi-modal screening pathway. These approaches need further investigation, and we propose a phased stepwise research framework to ensure proper evaluation of the use of a fast MRI examination as a screening test for prostate cancer.

Cancer Yield and Patterns of Follow-up for BI-RADS Category 3 after Screening Mammography Recall in the National Mammography Database

Background The literature supports the use of short-interval follow-up as an alternative to biopsy for lesions assessed as probably benign, Breast Imaging Reporting and Data System (BI-RADS) category 3, with an expected malignancy rate of less than 2%. Purpose To assess outcomes from 6-, 12-, and 24-month follow-up of probably benign findings first identified at recall from screening mammography in the National Mammography Database (NMD). Materials and Methods This retrospective study included women recalled from screening mammography with BI-RADS category 3 assessment at additional evaluation from January 2009 through March 2018 from 471 NMD facilities. Only the first BI-RADS category 3 occurrence for women aged 25 years or older with no personal history of breast cancer was analyzed, with biopsy or 2-year imaging follow-up. Cancer yield and positive predictive value of biopsies performed (PPV3) were determined at each follow-up. Results Among 45 202 women (median age, 55 years; range, 25-90 years) with a BI-RADS category 3 lesion, 1574 (3.5%) underwent biopsy at the time of lesion detection, yielding 72 cancers (cancer yield, 4.6%; 72 of 1574 women). For the remaining 43 628 women who accepted surveillance, 922 were seen within 90 days (with 78 lesions biopsied and 12 [15%] classified as malignant). The women still in surveillance (31 465 of 43 381 women [72.5%]) underwent follow-up mammography at 6 months. Of 3001 (9.5%) lesions biopsied, 456 (15.2%) were malignant (cancer yield, 1.5%; 456 of 31 465 women; 95% confidence interval [CI]: 1.3%, 1.6%). Among 18 748 of 25 997 women (72.1%) in surveillance who underwent follow-up at 12 months, 1219 (6.5%) underwent biopsy with 230 (18.9%) malignant lesions found (cancer yield, 1.2%; 230 of 18 748 women; 95% CI: 1.1%, 1.4%). Through 2-year follow-up, the biopsy rate was 11.2% (4894 of 43 628 women) with a cancer yield of 1.86% (810 malignancies found among 43 628 women; 95% CI: 1.73%, 1.98%) and a PPV3 of 16.6% (810 malignancies found among 4894 women). Conclusion In the National Mammography Database, Breast Imaging Reporting and Data System (BI-RADS) category 3 use is appropriate, with 1.86% cumulative cancer yield through 2-year follow-up. Of 810 malignancies, 468 (57.8%) were diagnosed at or before 6 months, validating necessity of short-interval follow-up of mammographic BI-RADS category 3 findings. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Moy in this issue.

Changes in the Utilization of the BI-RADS Category 3 Assessment in Recalled Patients Before and After the Implementation of Screening Digital Breast Tomosynthesis

RATIONALE AND OBJECTIVES

The purpose of this study was to compare the utilization of the Breast Imaging Reporting and Data System (BI-RADS) category 3 assessment in patients recalled from screening before and after the implementation of digital breast tomosynthesis (DBT).

MATERIALS AND METHODS

This was a retrospective review of 11,478 digital mammography (DM) screening exams and 9350 DM+DBT screening exams. Lesions assigned a BI-RADS category 3 at diagnostic exam were classified as architectural distortions, asymmetries, calcifications, masses, and "other" and followed for a minimum of 2 years.

RESULTS

The addition of DBT to screening DM resulted in a 30.4% relative reduction (10.3 women per 1000) in the utilization of BI-RADS category 3 compared to screening DM alone (3.4% for DM versus 2.4% for DM+DBT; p < 0.0001). There was a statistically significant change in the distribution of category 3 findings with DM+DBT characterized by an increase in calcifications and architectural distortions and a decrease in asymmetries. There was no change in category 3 assessment for masses. Although both cohorts had delayed cancer detection rates that exceeded the recommended 2% benchmark (2.3% for DM and 3.6% for DM+DBT), when limited to invasive malignancies, the delayed cancer detection rates were below the 2% benchmark (1.5% for DM and 0.9% for DM+DBT). Screening DM+DBT resulted in a 9.2% relative reduction in recall rate compared to DM (13.0% for DM versus 11.8% for DM+ DBT, p = 0.012).

CONCLUSION

Implementation of DBT in the screening population decreased the overall number of patients assigned to short-term follow-up by 10.3 per 1000 women while maintaining comparable rates of delayed cancer detection.

Evaluation of Palpable Breast Abnormalities

A palpable breast abnormality is one of the most common presenting clinical breast complaints. Although the majority of palpable abnormalities are benign, they are among the most common presenting symptoms of breast cancer, and those breast cancers detected symptomatically tend to have poorer prognosis than their screen-detected counterparts. Clinical breast examination is a vital part of the workup of palpable abnormalities. However, as physical exam features of most masses are not reliable for categorization of malignancy, imaging evaluation is necessary. Choice of imaging modality, which includes diagnostic mammography and breast ultrasound, is dependent upon patient age. Ultrasound is the primary imaging modality for evaluation of palpable masses in women younger than 30 years of age because of its high negative predictive value and sensitivity and lack of ionizing radiation. For women aged 30-39 years, ultrasound or mammography can be performed as the initial imaging evaluation, with ultrasound maintaining a high sensitivity in women younger than 40 years old. Mammography, often followed by ultrasound, is the recommended imaging evaluation sequence for women aged 40 and older. Utilization of advanced imaging modalities for evaluation of the palpable area of concern is not supported by evidence.

Variability in Individual Radiologist BI-RADS 3 Usage at a Large Academic Center: What's the Cause and What Should We Do About It?

RATIONALE AND OBJECTIVES

Although the breast imaging reporting and data system (BI-RADS) lists specific criteria for designating a lesion as BI-RADS category 3 (probably benign), there are no target benchmarks for BI-RADS 3 usage rates. This study investigates the variability of BI-RADS 3 rates among a group of academic breast imagers, with the goal of defining more precise utilization.

MATERIALS AND METHODS

We retrospectively reviewed all diagnostic mammograms performed between July 1, 2013 and August 8, 2017 at our academic institution. The percentage of diagnostic mammograms given a BI-RADS 3 assessment was compared between radiologists using the Chi-square test. We then evaluated for correlation between BI-RADS 3 rate and individual clinical metrics (eg, radiologist experience, cancer detection rate [CDR] and recall rate) using univariate linear regression.

RESULTS

The study included 13 breast imagers and 24,051 diagnostic breast examinations. There was significant variability in BI-RADS 3 rates between radiologists, ranging from 8.0% to 19.3% (p < 0.001). Increased BI-RADS 3 rates negatively correlated with BI-RADS 1 or 2 rate (p < 0.001) and positively correlated with recall rate (p = 0.03). There was no association between BI-RADS 3 rate and the radiologist's level of experience, BI-RADS 4 or 5 rate, or CDR.

CONCLUSION

We found significant variability in BI-RADS 3 usage, which seems to be used in place of BI-RADS 1 or 2 findings rather than to avoid biopsy recommendation. BI-RADS 3 rates also directly correlated with recall rate, suggesting a greater degree of uncertainty among specific radiologists. Importantly, increased usage of BI-RADS 3 did not correlate with provider experience or improved CDR.

Breast tomosynthesis for the clarification of mammographic BI-RADS 3 lesions can decrease follow-up examinations and enables immediate cancer diagnosis

Background The limited sensitivity of mammography in case of a high breast density often produces unclear or false-positive findings, so-called BI-RADS 3 lesions, which have to be followed up to prove benignity. Digital breast tomosynthesis (DBT) was developed to reduce such summation effects. Purpose To evaluate the influence of an additional DBT on the management of mammographic BI-RADS 3 findings and whether DBT can decrease the time to definitive diagnosis or not. Material and Methods We analyzed 87 patients with a mammographic non-calcified BI-RADS 3 lesion who underwent an additional DBT of the affected breast. A follow-up two-dimensional (2D) examination or a histological result of the lesion had to be available. The images were analyzed especially for the BI-RADS category and incremental diagnostic accuracy. Moreover, the inter-reader reliability and the radiation dose were evaluated. Results The BI-RADS category has been changed by the addition of DBT: 57.1% were assessed as BI-RADS 1 or 2, 4.6% as BI-RADS 4, and only 38.3% remained as BI-RADS 3. The intraclass correlation coefficient for the three readers showed a good agreement for inter-reader reliability. No false-negative examination was found in the follow-ups. Nine lesions were biopsied (seven benign, two malignant). Both malignant lesions were suspicious in the DBT (BI-RADS 4). A significant higher glandular dose was necessary for the DBT. Conclusion DBT has the potential to reduce the recall-rate of BI-RADS 3 lesions and to find and diagnose malignant lesions earlier than 2D mammography alone.

Growing BI-RADS category 3 lesions on follow-up breast ultrasound: malignancy rates and worrisome features

OBJECTIVE

  To determine the frequency and malignancy rate among growing Breast Imaging Reporting and Data System (BI-RADS) category 3 lesions diagnosed on follow-up breast ultrasound and to evaluate the radiological and clinical features associated with malignancy.  Methods:  Of the 38,482 women who underwent breast ultrasound between January 2010 and December 2011, 11,582 (30.1%) patients had 12,514 BI-RADS category 3 lesions. Patients whose lesions showed ≥20% enlargement on follow-up ultrasound were selected for this study. Radiological and clinical features including increase in the maximum diameter and anteroposterior dimension, morphological changes determined via ultrasound, palpability, multiplicity, new mass, baseline breast ultrasound indication and mammographic BI-RADS category were evaluated to determine their association with malignancy. Multivariate analyses were used to identify independent predictors of malignancy.  Results:  The frequency of growing BI-RADS category 3 lesions on follow-up ultrasound was 5.9% (738 of 12,514). Of 527 lesions examined in 459 patients with a follow-up duration of at least 24 months or with available pathological results, 26 proved to be malignant (4.9%). Multivariate analyses further indicated that sonographic morphological changes (OR, 7.662, p < 0.001) and development of suspicious features on follow-up mammography (OR, 3.812, p = 0.009) were associated with malignancy. Enlargement without associated suspicious mammography or sonographic morphological abnormalities had only 1.9 % (BI-RADS category 3) chance of malignancy.  Conclusion:  The malignancy rate for growing BI-RADS category 3 lesions is 4.9%. Sonographic morphological changes and suspicious mammographic features in these tumors are significantly associated with malignancy. Advances in knowledge: For lesions with an interval growth in the anteroposterior dimension of ≤50% without morphological changes, together with a benign mammogram, follow-up rather than an immediate biopsy can be recommended to reduce false-positive biopsy results. The risk of malignancy in lesions with a size increment but with no morphologic change on sonography is only 1.9%, compatible with continued BI-RADS category 3 classification.

BI-RADS 3: Current and Future Use of Probably Benign

PURPOSE OF REVIEW

Probably benign (BI-RADS 3) causes confusion for interpreting physicians and referring physicians and can induce significant patient anxiety. The best uses and evidence for using this assessment category in mammography, breast ultrasound, and breast MRI will be reviewed; the reader will have a better understanding of how and when to use BI-RADS 3.

RECENT FINDINGS

Interobserver variability in the use of BI-RADS 3 has been documented. The 5th edition of the BI-RADS atlas details the appropriate use of BI-RADS 3 for diagnostic mammography, ultrasound, and MRI, and discourages its use in screening mammography. Data mining, elastography, and diffusion weighted MRI have been evaluated to maximize the accuracy of BI-RADS 3.

SUMMARY

BI-RADS 3 is an evolving assessment category. When used properly, it reduces the number of benign biopsies while allowing the breast imager to maintain a high sensitivity for the detection of early stage breast cancer.

First ultrasound diagnosis of BI-RADS 3 lesions in young patients: Can 6-months follow-up be sufficient to assess stability?

OBJECTIVES

To evaluate the outcome of repeated short-term follow-up with ultrasound in no high-risk young patients with a BI-RADS3 lesion at first examination.

METHODS

In this IRB-approved study 492 women, aged 18-34 years (mean±standard deviation, 28±4.5years) with first breast ultrasound examination in 2012-2014 were retrospectively evaluated. Inclusion criteria were: at least one BI-RADS3 lesion and (a) biopsy/surgical excision or (b) follow-up of at least 18 months (including a 6-month follow-up). BI-RADS category assigned during follow-up and pathologic findings in cases undergoing biopsy/surgical excision were collected. At the 6- and 18-month follow-up the recommended biopsy rates (RBR) and the corresponding positive predictive value (PPV) were calculated.

RESULTS

In 97 patients, 151 BI-RADS3 lesions were identified. Biopsy/surgical excision was initially performed in 25/151 (16.5%) lesions. After 6-month, category was downgraded to BI-RADS1/2 in 23/126 (15.3%) and upgraded to BI-RADS4 in 9/126 lesions (7.1%). Pathological diagnosis of these lesions was fibroadenoma in 5 and benign phyllodes tumor in 4 cases (RBR 7%, PPV_bio 44.4%). After 18-month one lesion was classified BI-RADS4 and pathological diagnosis was fibroadenoma (RBR 1.1%, PPV_bio 0%).

CONCLUSIONS

Our preliminary data show that follow-up imaging performed after 18 months from a first BI-RADS3 diagnosis does not affect clinical treatment and 6-month follow-up may be sufficient to assess the stability of probably benign lesions.

Management for BI-RADS category 3 lesions detected in preoperative breast MR imaging of breast cancer patients

OBJECTIVE

To retrospectively evaluate characteristics of and determine appropriate follow-up recommendations for BI-RADS category 3 lesions detected in preoperative MRI of breast cancer patients.

METHODS

BI-RADS category 3 assessments were identified from the breast MRI database for 5,110 consecutive breast cancer patients who had undergone preoperative MRI and surgery. Patient and lesion characteristics, malignancy rate, and interval between lesion detection and cancer diagnosis were analysed. Histopathological results or imaging at or after 2-year follow-up were used as reference standards.

RESULTS

Of the 626 lesions, morphological features included a single focus in 26.5% (n = 166), multiple foci in 47.1% (n = 295), mass in 21.7% (n = 136) and non-mass enhancement in 4.6% (n = 29). Cancer was found in 0.8% (5/626) at a median interval of 50 months (range, 29-66 months). Malignancy rate according to morphological feature was: 1.8% (3/166) in a single focus, 0.7% (1/136) in mass and 3.4% (1/29) in non-mass enhancement. All detected cancers were stage 0 or IA.

CONCLUSIONS

Annual follow-up might be adequate for BI-RADS category 3 lesions detected at preoperative MRI because of the 0.8% (5/626) malignancy rate, long interval between lesion detection and cancer diagnosis, and early stage of diagnosed cancers.

KEY POINTS

• BI-RADS category 3 lesions on preoperative MRI had 0.8% malignancy rate. • All cancer diagnoses from BI-RADS 3 occurred after 24-month follow-up. • Annual follow-up might be adequate for BI-RADS 3 detected on preoperative MRI.

Outcomes of unconventional utilization of BI-RADS category 3 assessment at opportunistic screening

Background An important difficulty regarding the Breast Imaging Reporting and Data System (BI-RADS) category 3 assessment is the need for extensive diagnostic workup and an additional 6-month follow-up study. Purpose To evaluate the feasibility of the BI-RADS category 3 assessments at opportunistic screening. Material and Methods Mammography charts of 9062 screening patients in a major teaching hospital situated in an urban setting of a developing country were evaluated retrospectively (1997-2010). BI-RADS category 3 patients, called for a 6-month follow-up, which comprised a single-view spot or magnification mammogram. The length of follow-up period, compliance to periodic mammographic surveillance, cancer detection rate, and negative predictive values of category 3 assessments were calculated. Results Of the screened population, 9.2% were assigned BI-RADS category 3, and 31.2% of these cases were lost to follow-up. The mean follow-up period for 606 patients was 36.9 months. The negative predictive values for 6-month, 12-month, and final control studies were 90.9%, 87.5%, and 100%, respectively. Patient compliance for 6 months, 12 months, and any control evaluations beyond 12 months was low (50.0%, 29.8%, and 47.5%, respectively). Cancer detection rate was 0.8%. Conclusion Results of the study supports the feasibility of the BI-RADS category 3 assessments at opportunistic screening without any additional diagnostic workup. The practice of category 3 assessment following screening mammograms may be a more cost-effective method for developing countries with high recall rates and low resources in eliminating the maximum risk with minimum cost within the limits of available resources.

Assessment and Management of Challenging BI-RADS Category 3 Mammographic Lesions

Breast Imaging Reporting and Data System (BI-RADS) category 3 lesions are probably benign by definition and are recommended for short-interval follow-up after a diagnostic workup has been completed. Although the original lexicon-derived BI-RADS category 3 definition applied to lesions without prior imaging studies (when stability could not be determined), in clinical practice, many lesions with prior images may be assigned to BI-RADS category 3. Although the BI-RADS fifth edition specifically delineates lesions that are appropriate for categorization as probably benign, it also specifies that the interpreting radiologist may use his or her discretion and experience to justify a "watchful waiting" approach for lesions that do not meet established criteria. Examples of such lesions include evolving masses or calcifications suggestive of prior trauma and instances when stability cannot be ascertained because of image quality. Although interval change is an important feature of malignancy, many benign lesions also change over time; thus, use of prior imaging studies and ongoing imaging surveillance to demonstrate the evolution of a probably benign lesion is justified. Some examples of common pitfalls associated with inappropriate BI-RADS category 3 assessment include failure to use proper BI-RADS descriptors, failure to perform a complete diagnostic workup, and overreliance on negative ultrasonographic findings. When appropriately used, short-interval follow-up saves many patients from undergoing biopsy of benign lesions, without decreasing the rate of cancer detection. (©)RSNA, 2016.

Tomosynthesis in the Diagnostic Setting: Changing Rates of BI-RADS Final Assessment over Time

Purpose To evaluate the effect of tomosynthesis in diagnostic mammography on the Breast Imaging Reporting and Data System (BI-RADS) final assessment categories over time. Materials and Methods This retrospective study was approved by the institutional review board. The authors reviewed all diagnostic mammograms obtained during a 12-month interval before (two-dimensional [2D] mammography [June 2, 2010, to June 1, 2011]) and for 3 consecutive years after (tomosynthesis year 1 [2012], tomosynthesis year 2 [2013], and tomosynthesis year 3 [2014]) the implementation of tomosynthesis. The requirement to obtain informed consent was waived. The rates of BI-RADS final assessment categories 1-5 were compared between the 2D and tomosynthesis groups. The positive predictive values after biopsy (PPV3) for BI-RADS category 4 and 5 cases were compared. The mammographic features (masses, architectural distortions, calcifications, focal asymmetries) of lesions categorized as probably benign (BI-RADS category 3) and those for which biopsy was recommended (BI-RADS category 4 or 5) were reviewed. The χ(2) test was used to compare the rates of BI-RADS final assessment categories 1-5 between the two groups, and multivariate logistic regression analysis was performed to compare all diagnostic studies categorized as BI-RADS 3-5. Results There was an increase in the percentage of cases reported as negative or benign (BI-RADS category 1 or 2) with tomosynthesis (58.7% with 2D mammography vs 75.8% with tomosynthesis at year 3, P < .0001). A reduction in the percentage of probably benign (BI-RADS category 3) final assessments also occurred (33.3% with 2D mammography vs 16.4% with tomosynthesis at year 3, P < .0001). Although the rates of BI-RADS 4 or 5 assessments did not change significantly with tomosynthesis (8.0% with 2D mammography vs 7.8% with tomosynthesis at year 3, P = .2), there was a significant increase in the PPV3 (29.6% vs 50%, respectively; P < .0001). These trends increased during the 3 years of tomosynthesis use. Conclusion Tomosynthesis in the diagnostic setting resulted in progressive shifts in the BI-RADS final assessment categories over time, with a significant increase in the proportion of studies classified as normal, a continued decrease in the rate of studies categorized as probably benign, and improved diagnostic confidence in biopsy recommendations. (©) RSNA, 2016.

Characteristics, Malignancy Rate, and Follow-up of BI-RADS Category 3 Lesions Identified at Breast MR Imaging: Implications for MR Image Interpretation and Management

Purpose To (a) evaluate the frequency of Breast Imaging Reporting and Data System (BI-RADS) category 3 assessment in screening and diagnostic breast magnetic resonance (MR) imaging, (b) review findings considered indicative of BI-RADS category 3, and (c) determine outcomes of BI-RADS category 3 lesions, including upgrades, downgrades, and malignancy rates. Materials and Methods This retrospective study was approved by the institutional review board and compliant with HIPAA. The authors retrospectively reviewed the breast MR imaging database (2009-2011) to identify breast MR images classified as showing BI-RADS category 3 lesions. There were 9216 BI-RADS assessments in 5778 examinations (3360 women). Of the 9216 assessments, 567 (6%) in 483 women (average age, 47.2 years; median age, 47.0 years) were assigned BI-RADS category 3. In women with more than one BI-RADS category 3 lesion, the first lesion reported in the impression was used for data analysis. Outcomes data were available for 435 of the 483 women (90.1%). These women comprised the study cohort. Medical records from January 1, 2009, to May 31, 2015, were reviewed to obtain demographic characteristics and outcomes. χ(2) statistics and 95% exact confidence intervals (CIs) were constructed. Results MR imaging was performed for high-risk screening in 240 of the 435 patients (55.2%) and for diagnostic purposes in 195 (44.8%). Findings included mass (n = 125, 28.7%), focus (n = 111, 25.5%), nonmass enhancement (n = 80, 18.3%), moderate or marked background parenchymal enhancement (BPE) (n = 91, 20.9%), posttreatment changes (n = 16, 3.8%), and other findings (n = 12, 2.8%). Outcomes were as follows: 339 of the 435 patients (78%) did not have evidence of malignancy at more than 24 months, 28 (6.4%) underwent mastectomy (all benign), and 68 (15.6%) had lesion upgrades, with 11 cancers (2.5%). All 11 cancers were diagnosed in women with a genetic mutation or a personal history of breast cancer. No cancer was detected in cases of moderate or marked BPE. Conclusion Six percent of all breast MR imaging assessments were categorized as BI-RADS category 3, with a cancer rate of 2.5% (95% CI: 1.3%, 4.5%). All cancers were in women with a genetic mutation or personal history of breast cancer. Marked BPE does not necessitate a BI-RADS 3 assessment. (©) RSNA, 2016.

[Explorations of breast microcalcifications: Guidelines]

OBJECTIVES

To assess imaging performances for the detection, characterization and biopsy of breast microcalcifications and make recommendations.

MATERIALS AND METHODS

French and English publications were searched using PubMed, Cochrane Library and international learned societies recommendations.

RESULTS

Digital mammography (DR [Direct Radiography] and CR [Computed Radiography]) and screen-film mammography demonstrate good performances for the detection and the characterization of breast microcalcifications. Systematic use of the 2013 edition of the BI-RADS lexicon is recommended for description and characterization of microcalcifications. Faced with BI-RADS 4 or 5 microcalcifications, breast ultrasound is recommended but a normal result does not eliminate the diagnosis of cancer and other examination should be performed. Literature review does not allow recommending digital breast tomosynthesis, elastography or MRI to analyze microcalcifications. In case of probably benign microcalcifications (BI-RADS 3), six months, one year and at least two years follow-up are recommended. In case a biopsy is indicated, it is recommended to use a vacuum-assisted macrobiopsy system with 11-gauges needles or bigger. If no calcification is visible on the radiography of the specimen, it is recommended to obtain additional samples.

A history of breast cancer and older age allow risk stratification of mammographic BI-RADS 3 ratings in the diagnostic setting

OBJECTIVE

The objective was to investigate whether risk stratification of mammographic Breast Imaging: Reporting and Data System (BI-RADS) 3 can be accomplished in the diagnostic setting.

METHODS

We analyzed 4941 BI-RADS-3-rated patients (23 malignant outcomes) and built logistic-regression models with age, personal and family history of breast cancer, fibroglandular density, and additional mammographic findings as predictive variables.

RESULTS

A personal history of breast cancer (odds ratio: 5.53) and older age (odds ratio: 12.44/10.93 for age 50-64/>64) are independent risk factors. Patients with both risk factors have a risk >2%.

CONCLUSION

Biopsy may be warranted in older patients with a history of breast cancer who would be otherwise assigned BI-RADS 3.

Synchronous BI-RADS Category 3 Lesions on Preoperative Ultrasonography in Patients with Breast Cancer: Is Short-Term Follow-Up Appropriate?

Purpose

Breast ultrasonography (US) has been widely used in the preoperative examination of patients with breast cancer. Breast Imaging Reporting and Data System (BI-RADS) category 3 (C3) lesions (probably benign) are regarded as having a low probability of malignancy (≤2%). The purposes of this study were to verify the malignancy rates for synchronous BI-RADS C3 lesions in patients with breast cancer and consider appropriate management strategies for these lesions.

Methods

Between January 2010 and January 2013, a total of 161 patients underwent surgery in our institute for breast cancer and synchronous BI-RADS C3 lesions. In the US reports, we found records of 219 synchronous BI-RADS C3 nodules in 161 patients. They were excised during surgery for breast cancer management. Stepwise logistic regression analysis was used to identify predictors of malignancy for synchronous BI-RADS C3 lesions.

Results

The rate of malignancy among the 219 BI-RADS C3 lesions was 9.6%. In simple logistic regression analysis, the size of the primary tumor (p<0.001), pathologic T (pT) stage (p=0.002), and progesterone receptor (PR) status of the primary tumor (p=0.029) were significant predictive factors. In multiple logistic regression analysis, the pT stage and PR status of the primary tumor remained significant predictors (p=0.004 and p=0.003, respectively), and human epidermal growth factor receptor 2 (HER2) was identified as another significant factor (p=0.006).

Conclusion

In patients with breast cancer who are scheduled for surgery, needle biopsy or excision should be considered for synchronous BI-RADS C3 lesions identified on preoperative US when the primary tumor has the following risk factors: large size, high PR expression, and HER2 positivity.

Additional diagnostic value of MRI in patients with suspicious breast lesions based on ultrasound

OBJECTIVE

Biopsy has long been the standard approach in Breast Imaging Reporting and Data System® (BI-RADS) 4 or BI-RADS 5 (American College of Radiology, Reston, VA) lesions despite a wide variation in reported incidence of malignancy in BI-RADS 4 lesions. This study examined the diagnostic value of breast MRI as well as its ability to decrease unnecessary biopsies in patients with solid breast lesions who had an indication for biopsy.

METHODS

In this retrospective study, 277 breast lesions with a documented histological diagnosis as established by ultrasound-guided biopsy were included. All patients were female, and biopsy was performed owing to a BI-RADS score of 4 or 5 on ultrasonography. In addition, all patients had undergone MRI before biopsy. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of MRI in predicting malignancy were calculated.

RESULTS

When all lesions were analysed, sensitivity, specificity, NPV and PPV of MRI in detecting malignancy were 94.2%, 56.1%, 90.7% and 68.1%, respectively. When only ultrasonographic BI-RADS 4 lesions are considered, the corresponding figures were as follows: 90.9%, 56.7%, 93.8% and 46.4%, respectively. False-negative rate of MRI for the latter group of lesions was 2.6%. 42% of unnecessary biopsies were avoided in sonographic BI-RADS 4 lesions.

CONCLUSION

Despite promising results obtained in this study, dynamic MRI currently does not seem to be effective in ruling out the need for biopsy in the assessment of sonographic BI-RADS 4 lesions. However, advanced MRI techniques may assist in improving possible benefits of MRI in this patient group.

Patient compliance and diagnostic yield of 18-month unilateral follow-up in surveillance of probably benign mammographic lesions

OBJECTIVE

The purpose of this study is to determine the patient compliance with and diagnostic yield of 18-month unilateral mammography in surveillance of probably benign (BI-RADS category 3) lesions.

MATERIALS AND METHODS

This retrospective study identified lesions prospectively classified BI-RADS 3 in asymptomatic women from January 1, 2004, to December 31, 2008. Surveillance protocol for BI-RADS 3 lesions included 6-month (unilateral), 12-month (bilateral), 18-month (unilateral), and 24-month (bilateral) imaging, with subsequent annual screening. Demographics, surveillance data, BI-RADS upgrades and downgrades, and biopsy results were abstracted from the longitudinal medical record.

RESULTS

One thousand one hundred eighty-eight lesions in 1077 patients (mean age, 51.5 years; age range, 26-89 years) had BI-RADS 3 assessment, representing 1.07% of all screening examinations. The compliance rates for follow-up at 6, 12, 18, and 24 months were 83.3%, 75.9%, 54.8%, and 53.9%, respectively. Sixty lesions were upgraded to BI-RADS 4 or 5 during surveillance. Biopsy revealed 15 cancers (cancer yield of 1.47%) from 1017 lesions with either 24-month imaging stability or tissue diagnosis available. Five, six, one, and three cancers were detected at 6, 12, 18, and 24 months, respectively. Cancers were all stage 0 or 1 except for one stage 2A cancer. Seven hundred forty-four of 1188 (62.6%) BI-RADS 3 lesions were downgraded before completing 2-year surveillance.

CONCLUSION

Most (11/15 [73%]) breast cancers initially assessed as BI-RADS 3 are diagnosed at up to 12 months' surveillance. Eighteen-month unilateral mammography performed as BI-RADS 3 surveillance contributes minimally to cancer detection and has poor patient compliance.

Follow-up of probably benign lesions in non-screening breast diagnostics

PURPOSE

Our study addresses at the benefit of surveillance of probably benign lesions, detected outside mammographic screening, during a 3-year period.

METHODS

28,588 women (mean age 57 ± 12 years) were examined. Two independent radiologists read the mammogram as well as the supplemented ultrasound (in case of breast density ACR type 3 and 4). In the case of discordance a third expert considered whether further examination was indicated or not.

RESULTS

3,266 diagnostic procedures ended with BI-RADS 3 result and 2,512 (76.9 %) women underwent a follow-up examination. 295 (11.7 %) of them received assessment examination (imaging and/or biopsy) and 37 (12.5 %) (none of them palpable) ended with BI-RADS 6. This equals a tumor detection rate of 14.7/1,000. The ratio in situ:invasive was 7:10 (1:1.43) and the mean size was 11.1 ± 4.51 mm. In the total cohort, 536 carcinomas ended with BI-RADS 6 of them 17 % were in situ and 83 % were invasive breast cancers (ratio in situ:invasive 1:4.99), mean size was 13.8 ± 6.3 mm. The cancer detection ratio in these cases was 18.7/1,000.

CONCLUSIONS

The amount of detected tumors at follow-up of women with preceding BI-RADS 3 equates the associated potential of malignancy.

Benign core biopsy of probably benign breast lesions 2 cm or larger: correlation with excisional biopsy and long-term follow-up

Purpose:

To evaluate the accuracy of benign core biopsy of probably benign breast lesions (category 3) 2 cm or larger on the basis of excisional biopsy and long-term follow-up.

Methods:

We retrospectively reviewed 146 category 3 lesions in 146 patients 2 cm or larger which were diagnosed as benign by ultrasound (US)-guided core biopsy. Patients were initially diagnosed as benign at core needle biopsy and then followed up with excisional biopsy (surgical excision, n=91; US-guided vacuum assisted excision, n=35) or breast ultrasonography (n=20).

Results:

Of the 126 patients who underwent surgical excision or US-guided vacuum-assisted excision, 114 patients were diagnosed with benign lesions, 10 patients with borderline lesions (benign phyllodes tumor), and two patients with malignant phyllodes tumors. The probabilities of lesions being benign, borderline and malignant were 91.8% (134/146), 6.8% (10/146), and 1.4% (2/146), respectively. Of 13 patients who had growing masses on follow-up ultrasonography, three (23.1%) were non-benign (two benign phyllodes tumors and one malignant phyllodes tumor).

Conclusion:

US-guided core needle biopsy of probably benign breast mass 2 cm or larger was accurate (98.6%) enough to rule out malignancy. But, it was difficult to rule out borderline lesions even when they were diagnosed as benign.

Rate of malignancy in MRI-detected probably benign (BI-RADS 3) lesions

OBJECTIVE

The purpose of this study was to evaluate the malignancy rate in MRI-detected probably benign (BI-RADS 3) lesions in women without a history of breast cancer.

MATERIALS AND METHODS

In this study, 1265 patients underwent breast MRI during a 7-year period. One hundred and eight (8.5%) patients with a nonpalpable breast lesion classified as BI-RADS 3 at MRI and with a needle biopsy or adequate follow-up of at least 24 months were included. Statistical analysis included calculation of the negative predictive value with its 95% CI.

RESULTS

Of 108 lesions, 107 (99.1%) were correctly assessed as probably benign, resulting in a negative predictive value of 99.1% (95% CI, 94.99-99.98%). Histopathology was requested by the patient or referring physician in 44 patients. Of these, 43 (39.8%) lesions were classified as benign and one (0.9%) as malignant. There were no changes evident in any of the remaining 64 (59.2%) lesions during follow-up (range, 2-9 years).

CONCLUSION

In MRI-detected probably benign (BI-RADS 3) lesions, the malignancy rate is low and within the accepted cancer rate for mammographically or sonographically detected BI-RADS 3 lesions. Short-term follow-up MRI at intervals of 6, 12, and 24 months in MRI BI-RADS 3 lesions remains a strong tool with which to detect suspicious lesions. Interval changes in size, morphology, or enhancement are regarded as indicative of malignancy.

BI-RADS® 3 lesions at contrast-enhanced breast MRI: is an initial short-interval follow-up necessary?

BACKGROUND

Magnetic resonance imaging (MRI) BI-RADS® 3 lesions should have a very high probability of being benign. To prove benignity most institutions do follow-up MRI.

PURPOSE

To evaluate the necessity of initial short-interval follow-up after 6 months as it is suggested for mammographic BI-RADS®3 lesions.

MATERIAL AND METHODS

We analyzed 163 consecutive MRI-BI-RADS® 3 lesions on follow-up MRI: 75 masses (46%), 67 foci (41.1%), and 21 (12.9%) non-mass-like enhancing lesions (NMLE).

RESULTS

During MRI follow-up (mean time, 563 days) 20% of the lesions disappeared, 23% decreased, 52% did not change, and 4.9% showed increase. All increasing lesions were biopsied (5 benign, 2 ductal carcinoma in situ, 1 invasive carcinoma). The rate of malignancy was 1.8%. All malignant lesions (1 mass, 1 focus, 1 NMLE) showed increase at initial follow-up after a mean interval of 190 days.

CONCLUSION

In this study the malignancy rate of MRI-BI-RADS® 3 lesions corresponded to mammographic BI-RADS® 3 lesions. Initial short-interval MRI should be suggested to identify malignant MRI-BI-RADS® 3 lesions.

BI-RADS 3 for magnetic resonance imaging

A BI-RADS (Breast Imaging Reporting and Data System) 3, or probably benign, assessment is given in approximately 7% to 12% of breast magnetic resonance (MR) images. However, the imaging features of probably benign lesions on MR imaging have not been well defined. As with mammography and ultrasonography, a BI-RADS 3 assessment should be used only when there is a less than 2% likelihood of malignancy. The use of BI-RADS 3 for classically benign findings should be avoided. Certain masses, foci, and areas of nonmass enhancement may be categorized as probably benign on baseline MR imaging.

Probably benign lesions at screening breast US in a population with elevated risk: prevalence and rate of malignancy in the ACRIN 6666 trial

PURPOSE

To prospectively validate predefined breast ultrasonographic (US) Breast Imaging Reporting and Data System (BI-RADS) category 3 criteria in a multicenter setting in an elevated-risk population.

MATERIALS AND METHODS

The American College of Radiology Imaging Network 6666 database was reviewed for prospectively defined BI-RADS category 3 lesions. Patient characteristics, lesion US features at initial detection, and work-up recommendations were analyzed with descriptive statistics. Exact 95% confidence intervals (CIs) were given, where appropriate. Lesion reference standard was biopsy or a minimum of 1-year follow-up. In addition, malignancy rate for lesions that had at least 2 years of follow-up data or that had biopsy data was calculated.

RESULTS

Of 2662 participants, 519 (19.5%) had 745 BI-RADS category 3 lesions (25.5% of 2916 US lesions other than simple cysts), with a median size of 7 mm (range, 2-135 mm). The number of new BI-RADS category 3 lesions decreased with year 2-3 screening, but the percentage of new BI-RADS category 3 lesions was stable at 26.4% (506 of 1920 lesions), 23.6% (142 of 601 lesions), and 24.6% (97 of 395 lesions), respectively. Of 745 BI-RADS category 3 lesions, 124 (16.6%) were ultimately sampled for biopsy. Six malignancies (0.8% of BI-RADS category 3 lesions; 95% confidence interval [CI]: 0.3%, 1.7%) occurred in five (1.0%) of 519 participants: Five malignancies were invasive (median size, 10 mm; size range, 2-18 mm), and one was node positive. When the analysis is limited to lesions with at least 2-year follow-up or biopsy, the malignancy rate among BI-RADS category 3 lesions is 0.9% (95% CI: 0.3%, 2.0%). Three malignant BI-RADS category 3 lesions were sampled for biopsy because of a suspicious change at follow-up (two N0 lesions, one each at 6- and 12-month follow-up; one N1 lesion at 24-month follow-up), one was sampled for biopsy because of an upgrade after additional mammography (NX), one was found at mastectomy for another cancer (N0), and one was found at prophylactic contralateral mastectomy in the same patient (NX).

CONCLUSION

As BI-RADS category 3 lesions have a low malignancy rate (0.8%; 95% CI: 0.3%, 1.7%) and only 0.1% of the cancers had suspicious changes at 6-month follow-up and only one (17%; 95% CI: 0.4%, 64%) of six malignancies were node positive at detection (24-month follow-up), a recommendation of 1-year diagnostic follow-up may be appropriate for BI-RADS category 3 lesions detected at screening US. Online supplemental material is available for this article.

Probably benign breast MRI lesions: frequency, lesion type, and rate of malignancy

PURPOSE

To determine the frequency, malignancy rate, and imaging characteristics of BI-RADS (Breast Imaging Reporting and Data System) 3 MRI detected lesions.

MATERIALS AND METHODS

A total of 4370 consecutive contrast-enhanced breast MRI exams from March 1, 2004, to March 1, 2009, were retrospectively reviewed. The study was HIPAA (Health Insurance Portability Accountability Act) compliant and Institutional Review Board approved. The frequency of BI-RADS 3 MRI interpretations and lesion type, as well as malignancy rate at follow-up were calculated.

RESULTS

There were 348/4370 (8%) BI-RADS 3 exams performed on 345 patients. There were 125 foci (35.9%), 52 non-masslike enhancements (14.9%), and 171 masses (49.1%). There were 207 lesions with biopsy or imaging follow-up of at least 24 months (mean, 32 months; range, 6-77 months) of the BI-RADS 3 lesion. Five of these 207 (2.4%) lesions were found to be malignant.

CONCLUSION

Rate of malignancy among BI-RADS 3 MRI exams with follow-up was 2.4%. Types of lesions assigned as probably benign were 35.9% foci, 14.9% non-masslike enhancements, and 49.1% masses.

Optimal Policies for Reducing Unnecessary Follow-up Mammography Exams in Breast Cancer Diagnosis

Mammography is the most effective screening tool for early diagnosis of breast cancer. Based on the mammography findings, radiologists need to choose from one of the following three alternatives: 1) take immediate diagnostic actions including prompt biopsy to confirm breast cancer; 2) recommend a follow-up mammogram; 3) recommend routine annual mammography. There are no validated structured guidelines based on a decision-analytical framework to aid radiologists in making such patient management decisions. Surprisingly, only 15-45% of the breast biopsies and less than 1% of short-interval follow-up recommendations are found to be malignant, resulting in unnecessary tests and patient-anxiety. We develop a finite-horizon discrete-time Markov decision process (MDP) model that may help radiologists make patient-management decisions to maximize a patient's total expected quality-adjusted life years. We use clinical data to find the policies recommended by the MDP model and also compare them to decisions made by radiologists at a large mammography practice. We also derive the structural properties of the MDP model, including sufficiency conditions that ensure the existence of a double control-limit type policy.

Risk of malignancy in palpable solid breast masses considered probably benign or low suspicion: implications for management

OBJECTIVES

To determine whether solid palpable breast masses with benign sonographic features have less than 2% incidence of malignancy, allowing management by surveillance instead of biopsy.

METHODS

With Institutional Review Board approval, sonography reports of palpable solid breast masses from January 1, 2006, to December 31, 2009, prospectively classified as probably benign (American College of Radiology Breast Imaging Reporting and Data System [BI-RADS] 3) or low suspicion (BI-RADS 4A) were reviewed. Category 4A lesions were included because many palpable benign-appearing masses at our institution are classified as 4A for palpability. The BI-RADS categories were correlated with outcome data, comprising tissue diagnosis, imaging stability for at least 24 months, or decrease/resolution during imaging surveillance.

RESULTS

The study population included 440 lesions in 381 patients (mean age, 31.0 years; range, 15-68 years). A total of 161 lesions were prospectively classified as BI-RADS 3 and 279 as BI-RADS 4A. A total of 295 lesions (67%) had biopsy within 4.5 months of presentation, with 3 invasive malignancies; 145 of 440 lesions (33%) underwent surveillance. Forty-one lesions were considered benign for the following reasons: stability for at least 24 months (n = 28), benign tissue diagnosis during surveillance (n = 5), and decrease/resolution during follow-up (n = 8). The malignancy rate in lesions with adequate follow-up or biopsy was 3 of 336 (0.9%). All 3 malignancies occurred in women older than 40 years.

CONCLUSIONS

The incidence of malignancy in palpable solid breast masses classified as BI-RADS 3 or 4A in this study was less than 2%. In young women, surveillance rather than biopsy is appropriate for BI-RADS 3 palpable lesions. Palpability does not merit a BI-RADS 4A classification in solid masses with otherwise benign-appearing morphologic features, particularly in young women.

What is the optimal threshold at which to recommend breast biopsy?

Background

A 2% threshold, traditionally used as a level above which breast biopsy recommended, has been generalized to all patients from several specific situations analyzed in the literature. We use a sequential decision analytic model considering clinical and mammography features to determine the optimal general threshold for image guided breast biopsy and the sensitivity of this threshold to variation of these features.

Methodology/Principal Findings

We built a decision analytical model called a Markov Decision Process (MDP) model, which determines the optimal threshold of breast cancer risk to perform breast biopsy in order to maximize a patient’s total quality-adjusted life years (QALYs). The optimal biopsy threshold is determined based on a patient’s probability of breast cancer estimated by a logistic regression model (LRM) which uses demographic risk factors (age, family history, and hormone use) and mammographic findings (described using the established lexicon–BI-RADS). We estimate the MDP model's parameters using SEER data (prevalence of invasive vs. in situ disease, stage at diagnosis, and survival), US life tables (all cause mortality), and the medical literature (biopsy disutility and treatment efficacy) to determine the optimal “base case” risk threshold for breast biopsy and perform sensitivity analysis. The base case MDP model reveals that 2% is the optimal threshold for breast biopsy for patients between 42 and 75 however the thresholds below age 42 is lower (1%) and above age 75 is higher (range of 3–5%). Our sensitivity analysis reveals that the optimal biopsy threshold varies most notably with changes in age and disutility of biopsy.

Conclusions/Significance

Our MDP model validates the 2% threshold currently used for biopsy but shows this optimal threshold varies substantially with patient age and biopsy disutility.

Utility of targeted sonography in management of probably benign breast lesions identified on magnetic resonance imaging

OBJECTIVES

The purpose of this study was to determine the utility of targeted sonography in the management of probably benign breast lesions detected on magnetic resonance imaging (MRI).

METHODS

A total of 4370 consecutive contrast-enhanced breast MRI examinations from March 1, 2004, to March 1, 2009, were retrospectively reviewed. The study was Health Insurance Portability and Accountability Act compliant and Institutional Review Board approved. When targeted sonography was recommended for a Breast Imaging Reporting and Data System (BI-RADS) category 3 examination, results of the sonography and any subsequent breast pathologic examinations were recorded. The frequency of identifying the MRI-detected lesions and the rate at which the BI-RADS category was changed by sonography were calculated for mass and non-mass-like lesions.

RESULTS

Of the 4370 examinations, 349 (8%) had BI-RADS 3 findings in 346 patients. One hundred eighteen lesions underwent targeted sonography for evaluation of 85 masses and 33 areas of non-mass-like enhancement. Of these 118 lesions, 54 (46%) were seen on sonography. No cancers were detected on sonography in the areas of non-mass-like enhancement. Two of the 85 masses (2.4%) evaluated with targeted sonography had a malignant diagnosis before initiation of follow-up.

CONCLUSIONS

Selective use of targeted sonography, particularly in masses, may help identify some malignancies before initiating short-interval follow-up for MRI-detected BI-RADS 3 lesions.

The current role of vacuum assisted breast biopsy system in breast disease

The gold standard for breast biopsy procedures is currently an open excision of the suspected lesion. However, an excisional biopsy inevitably makes a scar. The cost and morbidity associated with this procedure has prompted many physicians to evaluate less invasive, alternative procedures. More recently, image-guided percutaneous core-needle biopsy has become a frequently used method for diagnosing palpable and non-palpable breast lesions. Although sensitivity rates for core-needle biopsy are high, it has the disadvantage of histological underestimation, which renders the management of atypical ductal hyperplasia, papillary lesions, and fibroepithelial lesions somewhat difficult. Vacuum assisted breast biopsy (VABB) was developed to overcome some of these negative aspects of core-needle biopsy. VABB allows for a sufficient specimen to be obtained with a single insertion and can provide a more accurate diagnosis and completely remove the lesion under real-time ultrasonic guidance. The advantage of complete lesion removal with VABB is to reduce or eliminate sampling error, to decrease the likelihood of a histological underestimation, to decrease imaging-histological discordance, to decrease the re-biopsy rate, and to diminish the likelihood of subsequent growth on follow-up. In recent years, with the advancement of VABB instruments and techniques, many outcome studies have reported on the use of VABB for resecting benign breast lesions with a curative intent. VABB is highly accurate for diagnosing suspicious breast lesions and is highly successful at treating presumed benign breast lesions. Thus, in the near future, VABB will be routinely offered to all appropriately selected patients.

The mammographic density of a mass is a significant predictor of breast cancer

PURPOSE

To determine whether the mammographic density of noncalcified solid breast masses is associated with malignancy and to measure the agreement between prospective and retrospective assessment.

MATERIALS AND METHODS

The institutional review board approved this study and waived informed consent. Three hundred forty-eight consecutive breast masses in 328 women who underwent image-guided or surgical biopsy between October 2005 and December 2007 were included. All 348 biopsy-proved masses were randomized and assigned to a radiologist who was blinded to biopsy results for retrospective assessment by using the Breast Imaging Reporting and Data System (retrospectively assessed data set). Clinical radiologists prospectively assessed the density of 180 of these masses (prospectively assessed data set). Pathologic result at biopsy was the reference standard. Benign masses were followed for at least 1 year by linking each patient to a cancer registry. Univariate analyses were performed on the retrospectively assessed data set. The association of mass density and malignancy was examined by creating a logistic model for the prospectively assessed data set. Agreement between prospective and retrospective assessments was calculated by using the κ statistic.

RESULTS

In the retrospectively assessed data set, 70.2% of high-density masses were malignant, and 22.3% of the isodense or low-density masses were malignant (P < .0001). In the prospective logistic model, high density (odds ratio, 6.6), irregular shape (odds ratio, 9.9), spiculated margin (odds ratio, 20.3), and age (β = 0.09, P < .0001) were significantly associated with the probability of malignancy. The κ value for prospective-retrospective agreement of mass density was 0.53.

CONCLUSION

High mass density is significantly associated with malignancy in both retrospectively and prospectively assessed data sets, with moderate prospective-retrospective agreement. Radiologists should consider mass density as a valuable descriptor that can stratify risk.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100328/-/DC1.

Interval growth of probably benign breast lesions on follow-up ultrasound: how can these be managed?

OBJECTIVES

To investigate the malignancy rate in probably benign lesions with interval growth on follow-up ultrasound (US) and the cut-off values for predicting malignancy.

METHODS

By retrospective reviewing 19,435 US examinations assessed as probably benign lesions, a total of 214 lesions with interval growth in 199 patients were included. The increased volume (%V),%V per month, the most increased diameter (D), and D per month were compared between malignant and benign lesions. Malignancy rates were compared between lesions with or without newly developed suspicious malignant features.

RESULTS

Twenty-two (10.3%) malignancies showed significant increase in%V,%V per month, D, and D per month compared with 192 (89.7%) benign lesions (p = 0.0083, <0.0001, <0.0001, and <0.0001, respectively). Fifteen (38.5%) of 39 lesions where suspicious features developed proved malignant, whereas 7 (4%) out of 175 without were malignant (p = 0.0011). In nodules without suspicious features, 24.2% of%V per month and 1.9 mm of D per month showed high sensitivity (85.7% and 71.4%) and specificity (67.8% and 97.6%) for predicting malignancy.

CONCLUSIONS

Probably benign lesions with interval growth should undergo prompt biopsy because of the 10.3% malignancy rate. In lesions where suspicious features developed, the malignancy rate increased to 38.5%.