Long-term risk of false-positive screening results and subsequent biopsy as a function of mammography use

Use of Artificial Intelligence for Reducing Unnecessary Recalls at Screening Mammography: A Simulation Study

OBJECTIVE

To conduct a simulation study to determine whether artificial intelligence (AI)-aided mammography reading can reduce unnecessary recalls while maintaining cancer detection ability in women recalled after mammography screening.

MATERIALS AND METHODS

A retrospective reader study was performed by screening mammographies of 793 women (mean age ± standard deviation, 50 ± 9 years) recalled to obtain supplemental mammographic views regarding screening mammography-detected abnormalities between January 2016 and December 2019 at two screening centers. Initial screening mammography examinations were interpreted by three dedicated breast radiologists sequentially, case by case, with and without AI aid, in a single session. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and recall rate for breast cancer diagnosis were obtained and compared between the two reading modes.

RESULTS

Fifty-four mammograms with cancer (35 invasive cancers and 19 ductal carcinomas in situ) and 739 mammograms with benign or negative findings were included. The reader-averaged AUC improved after AI aid, from 0.79 (95% confidence interval [CI], 0.74-0.85) to 0.89 (95% CI, 0.85-0.94) (p < 0.001). The reader-averaged specificities before and after AI aid were 41.9% (95% CI, 39.3%-44.5%) and 53.9% (95% CI, 50.9%-56.9%), respectively (p < 0.001). The reader-averaged sensitivity was not statistically different between AI-unaided and AI-aided readings: 89.5% (95% CI, 83.1%-95.9%) vs. 92.6% (95% CI, 86.2%-99.0%) (p = 0.053), although the sensitivities of the least experienced radiologists before and after AI aid were 79.6% (43 of 54 [95% CI, 66.5%-89.4%]) and 90.7% (49 of 54 [95% CI, 79.7%-96.9%]), respectively (p = 0.031). With AI aid, the reader-averaged recall rate decreased by from 60.4% (95% CI, 57.8%-62.9%) to 49.5% (95% CI, 46.5%-52.4%) (p < 0.001).

CONCLUSION

AI-aided reading reduced the number of recalls and improved the diagnostic performance in our simulation using women initially recalled for supplemental mammographic views after mammography screening.

Tumor volume doubling time estimated from digital breast tomosynthesis mammograms distinguishes invasive breast cancers from benign lesions

OBJECTIVES

The aim of this study was to determine whether lesion size metrics on consecutive screening mammograms could predict malignant invasive carcinoma versus benign lesion outcome.

METHODS

We retrospectively reviewed suspicious screen-detected lesions confirmed by biopsy to be invasive breast cancers or benign that were visible on current and in-retrospect prior screening mammograms performed with digital breast tomosynthesis from 2017 to 2020. Four experienced radiologists recorded mammogram dates, breast density, lesion type, lesion diameter, and morphology on current and prior exams. We used logistic regression models to evaluate the association of invasive breast cancer outcome with lesion size metrics such as maximum dimension, average dimension, volume, and tumor volume doubling time (TVDT).

RESULTS

Twenty-eight patients with invasive ductal carcinoma or invasive lobular carcinoma and 40 patients with benign lesions were identified. The mean TVDT was significantly shorter for invasive breast cancers compared to benign lesions (0.84 vs. 2.5 years; p = 0.0025). Patients with a TVDT of less than 1 year were shown to have an odds ratio of invasive cancer of 6.33 (95% confidence interval, 2.18-18.43). Logistic regression adjusted for age, lesion maximum dimension, and lesion volume demonstrated that shorter TVDT was the size variable significantly associated with invasive cancer outcome.

CONCLUSION

Invasive breast cancers detected on current and in-retrospect prior screening mammograms are associated with shorter TVDT compared to benign lesions. If confirmed to be sufficiently predictive of benignity in larger studies, lesions visible on mammograms which in comparison to prior exams have longer TVDTs could potentially avoid additional imaging and/or biopsy.

KEY POINTS

• We propose tumor volume doubling time as a measure to distinguish benign from invasive breast cancer lesions. • Logistic regression results summarized the utility of the odds ratio in retrospective clinical mammography data.

Breast cancer screening in average and high-risk women

Breast cancer is the most common cancer among females worldwide with rising incidence. In the United States, screening mammography and advances in therapy have lowered mortality by 41% since 1990. Screening mammography is supported by randomized control trials (RCT), observational studies, and computer model data. Digital breast tomosynthesis is a new technology that addresses limitations in mammography resulting from overlapping breast tissue, improving its sensitivity and specificity. Patients at high risk for breast cancer include those with a ≥20% lifetime risk, high-risk germline mutation, or history of thoracic radiation treatment between 10-30 years of age. Such patients are recommended to undergo annual screening mammography and adjunctive annual screening breast MRI. Patients unable to undergo MRI may undergo whole breast ultrasound or contrast-enhanced mammography. Pregnant and lactating patients at average risk for breast cancer are recommended to undergo age-appropriate screening mammography.

Breast Cancer Screening Recommendations Inclusive of All Women at Average Risk: Update from the ACR and Society of Breast Imaging

Breast cancer remains the most common nonskin cancer, the second leading cause of cancer deaths, and the leading cause of premature death in US women. Mammography screening has been proven effective in reducing breast cancer deaths in women age 40 years and older. A mortality reduction of 40% is possible with regular screening. Treatment advances cannot overcome the disadvantage of being diagnosed with an advanced-stage tumor. The ACR and Society of Breast Imaging recommend annual mammography screening beginning at age 40, which provides the greatest mortality reduction, diagnosis at earlier stage, better surgical options, and more effective chemotherapy. Annual screening results in more screening-detected tumors, tumors of smaller sizes, and fewer interval cancers than longer screening intervals. Screened women in their 40s are more likely to have early-stage disease, negative lymph nodes, and smaller tumors than unscreened women. Delaying screening until age 45 or 50 will result in an unnecessary loss of life to breast cancer and adversely affects minority women in particular. Screening should continue past age 74 years, without an upper age limit unless severe comorbidities limit life expectancy. Benefits of screening should be considered along with the possibilities of recall for additional imaging and benign biopsy and the less tangible risks of anxiety and overdiagnosis. Although recall and biopsy recommendations are higher with more frequent screening, so are life-years gained and breast cancer deaths averted. Women who wish to maximize benefit will choose annual screening starting at age 40 years and will not stop screening prematurely.

Annual Screening Mammography Associated With Lower Stage Breast Cancer Compared With Biennial Screening

OBJECTIVE. The purpose of this study was to compare breast cancer characteristics and treatment regimens among women undergoing annual versus nonannual screening mammography. MATERIALS AND METHODS. In this retrospective, institutional review board-approved, HIPAA-compliant cohort study, a breast cancer database was queried for patients who received a mammographic or clinical diagnosis of breast cancer during 2016-2017. Annual versus biennial and annual versus nonannual (biennial and triennial) mammography screening cohorts were compared using t tests or Wilcoxon rank sum tests for continuous variables and chi-square or Fisher exact tests for categoric variables. RESULTS. A total of 490 patients were diagnosed with breast cancer during 2016-2017. Among these women, 245 had an assignable screening frequency and were 40-84 years old (mean, 61.8 ± 9.9 [SD] years; median, 62 years). Screening frequency was annual for 200 of these 245 patients (81.6%), biennial for 32 (13.1%), and triennial for 13 (5.3%). Annual screening resulted in fewer late-stage presentations (AJCC stage II, III, or IV in 48 of 200 patients undergoing annual [24.0%] vs 14 of 32 undergoing biennial [43.8%; p = .02] and vs 20 of 45 undergoing nonannual screening [44.4%; p = .006]), fewer interval cancers (21 of 200 for annual [10.5%] vs 12 of 32 for biennial [37.5%; p < .001] and vs 15 of 45 for nonannual [33.3%; p < .001]), and smaller mean tumor diameter (1.4 ± 1.2 cm for annual vs 1.8 ± 1.6 cm for biennial [p = .04] and vs 1.8 ± 1.5 cm nonannual [p = .03]). Lower AJCC stage, fewer interval cancers, and smaller tumor diameter also persisted among postmenopausal women undergoing annual screening. Patients undergoing biennial and nonannual screening showed nonsignificant greater use of axillary lymph node dissection (annual, 24 of 200 [12.0%]; biennial, 6 of 32 [18.8%]; nonannual, 7 of 45 [15.6%]) and chemotherapy (annual, 55 of 200 [27.5%]; biennial, 12 of 32 [37.5%]; nonannual, 16 of 45 [35.6%]). CONCLUSION. Annual mammographic screening was associated with lower breast cancer stage and fewer interval cancers than biennial or nonannual screening.

Overdiagnosis and Risks of Breast Cancer Screening

Since its widespread introduction 30 years ago, screening mammography has contributed to substantial reduction in breast cancer-associated mortality, ranging from 15% to 50% in observational trials. It is currently the best examination available for the early diagnosis of breast cancer, when survival and treatment options are most favorable. However, like all medical tests and procedures, screening mammography has associated risks, including overdiagnosis and overtreatment, false-positive examinations, false-positive biopsies, and radiation exposure. Women should be aware of the benefits and risks of screening mammography in order to make the most appropriate care decisions for themselves.

Comparison of cumulative false-positive risk of screening mammography in the United States and Denmark

INTRODUCTION

In the United States (US), about one-half of women screened with annual mammography have at least one false-positive test after ten screens. The estimate for European women screened ten times biennially is much lower. We evaluate to what extent screening interval, mammogram type, and statistical methods, can explain the reported differences.

METHODS

We included all screens from women first screened at age 50-69 years in the US Breast Cancer Surveillance Consortium (BCSC) (n=99,455) between 1996-2010, and from two population-based mammography screening programs in Denmark (n=230,452 and n=400,204), between 1991-2012 and 1993-2013, respectively. Model-based cumulative false-positive risks were computed for the entire sample, using two statistical methods (Hubbard Njor) previously used to estimate false-positive risks in the US and Europe.

RESULTS

Empirical cumulative risk of at least one false-positive test after eight (annual or biennial) screens was 41.9% in BCSC, 16.1% in Copenhagen, and 7.4% in Funen. Variation in screening interval and mammogram type did not explain the differences by country. Using the Hubbard method, the model-based cumulative risks after eight screens was 45.1% in BCSC, 9.6% in Copenhagen, and 8.8% in Funen. Using the Njor method, these risks were estimated to be 43.6, 10.9 and 8.0%.

CONCLUSION

Choice of statistical method, screening interval and mammogram type does not explain the substantial differences in cumulative false-positive risk between the US and Europe.

The Burden of False-Positive Results in Analog and Digital Screening Mammography: Experience of the Nova Scotia Breast Screening Program

Purpose

The Canadian Task Force on Preventive Health Care released recommendations for breast cancer screening, in part, based on harms associated with screening. The purpose of this study was to describe the rate of false-positive (FP) screening mammograms and to describe the extent of the investigations after an FP.

Methods

A cohort was identified that consisted of all screening mammograms performed through the Screening Program (2000-2011) with patients ages 40-69 years at screening. Rates of FP screening mammograms were calculated as well as rates of further investigations required, including additional imaging, needle core biopsy, and surgery. Analyses were stratified by 10-year age group, screening status (first vs rescreen), and technology.

Results

A total of 608,088 screening mammograms were included. The FP rate varied by age group, and decreased with increasing age (digital, 40-49 years old, FP = 8.0%; 50-59 years old, FP = 6.3%; 60-69 years old, FP = 4.6%). The FP rate also varied by screening status (digital, first screen, FP = 12.0%; rescreen, FP = 5.6%), and this difference was consistent across age groups. The need for further investigation varied by age group, with invasive procedures being more heavily used as women age (digital, rescreen group, surgery: 40-49 years old, 1.1%; 50-59 years old 1.6%, 60-69 years old, 1.8%).

Conclusions

Both the FP screening mammogram rate and the degree to which further investigation was required varied by age group and screening status. Reporting on these rates should form part of the evaluation of screening performance.

Evolving paradigm for imaging, diagnosis, and management of DCIS

Our understanding of the biology of breast cancer has dramatically expanded over the past decade, revealing that breast cancer is a heterogeneous group of diseases. This new knowledge can generate insights to improve screening performance and the management of ductal carcinoma in situ. In this article, the authors review the current state of the science of breast cancer and tools that can be used to improve screening and risk assessment. They describe several opportunities to improve clinical screening: (1) radiologists interpreting mammograms should aim to differentiate between the risk for invasive cancer and ductal carcinoma in situ to better assess the time frame for disease progression and the need for and optimal timing of biopsy; (2) imaging features associated with low risk, slow-growing cancer versus high risk, fast-growing cancer should be better defined and taught; and (3) as we learn more about assessing an individual's risk for developing breast cancer, we should incorporate these factors into a strategy for personalized screening to maximize benefit and minimize harm.

Circulating miR-148b and miR-133a as biomarkers for breast cancer detection

Circulating microRNAs have drawn a great deal of attention as promising novel biomarkers for breast cancer. However, to date, the results are mixed. Here, we performed a three-stage microRNA analysis using plasma samples from breast cancer patients and healthy controls, with efforts taken to address several pitfalls in detection techniques and study design observed in previous studies. In the discovery phase with 122 Caucasian study subjects, we identified 43 microRNAs differentially expressed between breast cancer cases and healthy controls. When those microRNAs were compared with published data from other studies, we identified three microRNAs, including miR-148b, miR-133a and miR-409-3p, whose plasma levels were significantly higher in breast cancer cases than healthy controls and were also significant in previous independent studies. In the validation phase with 50 breast cancer cases and 50 healthy controls, we validated the associations with breast cancer detection for miR-148b and miR-133a (P = 1.5×10-6 and 1.3×10-10, respectively). In the in-vitro study phase, we found that both miR-148b and miR-133a were secreted from breast cancer cell lines, showing their secretory potential and possible tumor origin. Thus, our data suggest that both miR-148b and miR-133a have potential use as biomarkers for breast cancer detection.

Reducing false-positive biopsies: a pilot study to reduce benign biopsy rates for BI-RADS 4A/B assessments through testing risk stratification and new thresholds for intervention

The aim of this study is to evaluate Breast Imaging Reporting and Data Systems (BI-RADS) 4A/B subcategory risk estimates for ductal carcinoma in situ (DCIS) and invasive cancer (IC), determining whether changing the proposed cutoffs to a higher biopsy threshold could safely increase cancer-to-biopsy yields while minimizing false-positive biopsies. A prospective clinical trial was performed to evaluate BI-RADS 4 lesions from women seen in clinic between January 2006 and March 2007. An experienced radiologist prospectively estimated a percent risk-estimate for DCIS and IC. Truth was determined by histopathology or 4-year follow-up negative for malignancy. Risk estimates were used to generate receiver-operating characteristic (ROC) curves. Biopsy rates, cancer-to-biopsy yields, and type of malignancies missed were then calculated across postulated risk thresholds. A total of 124 breast lesions were evaluated from 213 women. An experienced radiologist gave highly accurate risk estimates for IC, DCIS alone, or the combination with an area under ROC curve of 0.91 (95 % CI 0.84–0.99) (p < 0.001), 0.81 (95 % CI 0.69–0.93) (p = 0.011), and 0.89 (95 % CI 0.83–0.95) (p < 0.001), respectively. The cancer-to-biopsy yield was 30 %. Three hypothetical thresholds for intervention were analyzed: (1) DCIS or IC ≥ 10 %; (2) DCIS ≥ 50 % or IC ≥ 10 %; and (3) IC ≥ 10 %, which translated to 22, 48, and 56 % of biopsies avoided; cancer-to-biopsy yields of 36, 47, and 46 %; and associated chance of missing an IC of 0, 1, and 2 %, respectively. Expert radiologists estimate risk of IC and DCIS with a high degree of accuracy. Increasing the cut off point for recommending biopsy, substituting with a short-term follow-up protocol with biopsy if any change, may safely reduce the number of false-positive biopsies.

Stereoscopic digital mammography: improved specificity and reduced rate of recall in a prospective clinical trial

PURPOSE

To compare stereoscopic digital mammography (DM) with standard DM for the rate of patient recall and the detection of cancer in a screening population at elevated risk for breast cancer.

MATERIALS AND METHODS

Starting in September 2004 and ending in December 2007, this prospective HIPAA-compliant, institutional review board-approved screening trial, with written informed consent, recruited female patients at elevated risk for breast cancer (eg, personal history of breast cancer or breast cancer in a close relative). A total of 1298 examinations from 779 patients (mean age, 58.6 years; range, 32-91 years) comprised the analyzable data set. A paired study design was used, with each enrolled patient serving as her own control. Patients underwent both DM and stereoscopic DM examinations in a single visit, findings of which were interpreted independently by two experienced radiologists, each using a Breast Imaging Reporting and Data System (BI-RADS) assessment (BI-RADS category 0, 1, or 2). All patients determined to have one or more findings with either or both modalities were recalled for standard diagnostic evaluation. The results of 1-year follow-up or biopsy were used to determine case truth.

RESULTS

Compared with DM, stereoscopic DM showed significantly higher specificity (91.2% [1167 of 1279] vs 87.8% [1123 of 1279]; P = .0024) and accuracy (90.9% [1180 of 1298] vs 87.4% [1135 of 1298]; P = .0023) for detection of cancer. Sensitivity for detection of cancer was not significantly different for stereoscopic DM (68.4% [13 of 19]) compared with DM (63.2% [12 of 19], P .99). The recall rate for stereoscopic DM was 9.6% (125 of 1298) and that for DM was 12.9% (168 of 1298) (P = .0018).

CONCLUSION

Compared with DM, stereoscopic DM significantly improved specificity for detection of cancer, while maintaining comparable sensitivity. The recall rate was significantly reduced with stereoscopic DM compared with DM.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120382/-/DC1.

Long-term benefits of breast screening

SUMMARY A series of prospective randomized controlled trials of breast cancer screening convincingly demonstrated the efficacy of an invitation to mammography to reduce breast cancer deaths. Evaluation efforts since then have focused on the absolute benefit of breast cancer screening overall and in age-specific subgroups, with various measures of benefit versus harm, and an interest in the degree to which improvements in therapy and women’s improved reporting of symptoms have eclipsed some or all of the benefit of detection of occult disease by mammography. In this article we describe the summary measures of the efficacy of mammography demonstrated by the randomized controlled trials, the importance of long-term follow-up to measure the absolute benefit of mammography and the balance of benefits and harms, including the number needed to screen to save one life and overdiagnosis.

Predictive value of BI-RADS classification for breast imaging in women under age 50

In this study, we assessed the positive-predictive value (PPV) of mammography and/or ultrasonography in women age 50 based on recommendations for biopsies and final pathology results. We performed a retrospective analysis of all mammography and ultrasonography reports issued from 9/2005 to 1/2007 resulting in biopsy among women aged 18-50 at a large county hospital. Data included demographics, imaging modality, breast density, type of finding, BI-RADS, and final pathology. Results were compared to women aged >50 at the same institution. Four hundred and seventy-five biopsies in 395 patients were reviewed. The PPV of BI-RADS 3 (n = 11) was 9.1%, BI-RADS 4 (n = 440) 5.9%, and BI-RADS 5 (n = 24) 66.7%. Forty three (9%) were malignant, of which 31 (6.5%) were invasive carcinomas and 12 (2.5%) were noninvasive. None of the biopsies on patients aged <30 were malignant. Recommended biopsies based on mammography alone were malignant in 20.2% (20/99) compared to 3.4% (7/205) for ultrasonography alone, and 8.9% (15/168) for both mammography and ultrasonography. Suspicious calcifications were malignant in 25% compared to 6.8% for masses/nodules and 3.6% for cysts. Lesions larger than 2 cm are more likely to be malignant (11.8%) than lesions between 1 and 2 cm (3.6%) or below 1 cm (4.3%). The PPV of the current screening modalities diminishes markedly in women under the age of 50 and even more below the age of 40. Calcifications and masses larger than 2 cm should be biopsied, but the current BI-RADS criteria may benefit from revision for other findings in young patients.

Modelling the cumulative risk of a false-positive screening test

The goal of a screening test is to reduce morbidity and mortality through the early detection of disease; but the benefits of screening must be weighed against potential harms, such as false-positive (FP) results, which may lead to increased healthcare costs, patient anxiety, and other adverse outcomes associated with diagnostic follow-up procedures. Accurate estimation of the cumulative risk of an FP test after multiple screening rounds is important for program evaluation and goal setting, as well as informing individuals undergoing screening what they should expect from testing over time. Estimation of the cumulative FP risk is complicated by the existence of censoring and possible dependence of the censoring time on the event history. Current statistical methods for estimating the cumulative FP risk from censored data follow two distinct approaches, either conditioning on the number of screening tests observed or marginalizing over this random variable. We review these current methods, identify their limitations and possibly unrealistic assumptions, and propose simple extensions to address some of these limitations. We discuss areas where additional extensions may be useful. We illustrate methods for estimating the cumulative FP recall risk of screening mammography and investigate the appropriateness of modelling assumptions using 13 years of data collected by the Breast Cancer Surveillance Consortium (BCSC). In the BCSC data we found evidence of violations of modelling assumptions of both classes of statistical methods. The estimated risk of an FP recall after 10 screening mammograms varied between 58% and 77% depending on the approach used, with an estimate of 63% based on what we feel are the most reasonable modelling assumptions.

Effectiveness of early detection on breast cancer mortality reduction in Catalonia (Spain)

Background

At present, it is complicated to use screening trials to determine the optimal age intervals and periodicities of breast cancer early detection. Mathematical models are an alternative that has been widely used. The aim of this study was to estimate the effect of different breast cancer early detection strategies in Catalonia (Spain), in terms of breast cancer mortality reduction (MR) and years of life gained (YLG), using the stochastic models developed by Lee and Zelen (LZ).

Methods

We used the LZ model to estimate the cumulative probability of death for a cohort exposed to different screening strategies after T years of follow-up. We also obtained the cumulative probability of death for a cohort with no screening. These probabilities were used to estimate the possible breast cancer MR and YLG by age, period and cohort of birth. The inputs of the model were: incidence of, mortality from and survival after breast cancer, mortality from other causes, distribution of breast cancer stages at diagnosis and sensitivity of mammography. The outputs were relative breast cancer MR and YLG.

Results

Relative breast cancer MR varied from 20% for biennial exams in the 50 to 69 age interval to 30% for annual exams in the 40 to 74 age interval. When strategies differ in periodicity but not in the age interval of exams, biennial screening achieved almost 80% of the annual screening MR. In contrast to MR, the effect on YLG of extending screening from 69 to 74 years of age was smaller than the effect of extending the screening from 50 to 45 or 40 years.

Conclusion

In this study we have obtained a measure of the effect of breast cancer screening in terms of mortality and years of life gained. The Lee and Zelen mathematical models have been very useful for assessing the impact of different modalities of early detection on MR and YLG in Catalonia (Spain).