Association of recall rates with sensitivity and positive predictive values of screening mammography

Swiss Pilot Low-Dose CT Lung Cancer Screening Study: First Baseline Screening Results

This pilot study conducted in Switzerland aims to assess the implementation, execution, and performance of low-dose CT lung cancer screening (LDCT-LCS). With lung cancer being the leading cause of cancer-related deaths in Switzerland, the study seeks to explore the potential impact of screening on reducing mortality rates. However, initiating a lung cancer screening program poses challenges and depends on country-specific factors. This prospective study, initiated in October 2018, enrolled participants meeting the National Lung Cancer Study criteria or a lung cancer risk above 1.5% according to the PLCOm2012 lung cancer risk-model. LDCT scans were assessed using Lung-RADS. Enrollment and follow-up are ongoing. To date, we included 112 participants, with a median age of 62 years (IQR 57-67); 42% were female. The median number of packs smoked each year was 45 (IQR 38-57), and 24% had stopped smoking before enrollment. The mean PLCOm2012 was 3.7% (±2.5%). We diagnosed lung cancer in 3.6% of participants (95%, CI:1.0-12.1%), with various stages, all treated with curative intent. The recall rate for intermediate results (Lung-RADS 3,4a) was 15%. LDCT-LCS in Switzerland, using modified inclusion criteria, is feasible. Further analysis will inform the potential implementation of a comprehensive lung cancer screening program in Switzerland.

Artificial intelligence assistance for women who had spot compression view: reducing recall rates for digital mammography

Background

Mammography yields inevitable recall for indeterminate findings that need to be confirmed with additional views.

Purpose

To explore whether the artificial intelligence (AI) algorithm for mammography can reduce false-positive recall in patients who undergo the spot compression view.

Material and Methods

From January to December 2017, 236 breasts from 225 women who underwent the spot compression view due to focal asymmetry, mass, or architectural distortion on standard digital mammography were included. Three readers who were blinded to the study purpose, patient information, previous mammograms, following spot compression views, and any clinical or pathologic reports retrospectively reviewed 236 standard mammograms and determined the necessity of patient recall and the probability of malignancy per breast, first without and then with AI assistance. The performances of AI and the readers were evaluated with the recall rate, area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and accuracy.

Results

Among 236 examinations, 8 (3.4%) were cancers and 228 (96.6%) were benign. The recall rates of all three readers significantly decreased with AI assistance ( P < 0.05). The reader-averaged recall rates significantly decreased with AI assistance regardless of breast composition (fatty breasts: 32.7% to 24.1%m P = 0.002; dense breasts: 33.6% to 21.2%, P < 0.001). The reader-averaged AUC increased with AI assistance and was comparable to that of standalone AI (0.835 vs. 0.895; P = 0.234). The reader-averaged specificity (71.2% to 79.8%, P < 0.001) and accuracy (71.3% to 79.7%, P  < 0.001) significantly improved with AI assistance.

Conclusion

AI assistance significantly reduced false-positive recall without compromising cancer detection in women with focal asymmetry, mass, or architectural distortion on standard digital mammography regardless of mammographic breast density.

Patient Navigation Can Improve Breast Cancer Outcomes among African American Women in Chicago: Insights from a Modeling Study

African American (AA) women experience much greater mortality due to breast cancer (BC) than non-Latino Whites (NLW). Clinical patient navigation is an evidence-based strategy used by healthcare institutions to improve AA women's breast cancer outcomes. While empirical research has demonstrated the potential effect of navigation interventions for individuals, the population-level impact of navigation on screening, diagnostic completion, and stage at diagnosis has not been assessed. An agent-based model (ABM), representing 50-74-year-old AA women and parameterized with locally sourced data from Chicago, is developed to simulate screening mammography, diagnostic resolution, and stage at diagnosis of cancer. The ABM simulated three counterfactual scenarios: (1) a control setting without any navigation that represents the "standard of care"; (2) a clinical navigation scenario, where agents receive navigation from hospital-affiliated staff; and (3) a setting with network navigation, where agents receive clinical navigation and/or social network navigation (i.e., receiving support from clinically navigated agents for breast cancer care). In the control setting, the mean population-level screening mammography rate was 46.3% (95% CI: 46.2%, 46.4%), the diagnostic completion rate was 80.2% (95% CI: 79.9%, 80.5%), and the mean early cancer diagnosis rate was 65.9% (95% CI: 65.1%, 66.7%). Simulation results suggest that network navigation may lead up to a 13% increase in screening completion rate, 7.8% increase in diagnostic resolution rate, and a 4.9% increase in early-stage diagnoses at the population-level. Results suggest that systems science methods can be useful in the adoption of clinical and network navigation policies to reduce breast cancer disparities.

Breast Density Awareness and Knowledge in a Mammography Screening Cohort of Predominantly Hispanic Women: Does Breast Density Notification Matter?

BACKGROUND

New York State law mandates that women with dense breasts receive a written notification of their breast density (BD) and its implications, but data on the impact of dense breast notification (DBN) on BD awareness and knowledge in diverse populations remain limited.

METHODS

Between 2016 and 2018, we collected survey and mammographic data from 666 women undergoing screening mammography in New York City (ages 40-60, 80% Hispanic, 69% Spanish-speaking) to examine the impact of prior DBN on BD awareness by sociodemographic and breast cancer risk factors, and describe BD knowledge by sources of information.

RESULTS

Only 24.8% of the overall sample and 34.9% of women receiving DBN had BD awareness. In multivariable models adjusting for DBN, awareness was significantly lower in women who were Spanish-speaking [OR, 0.16; 95% confidence interval (CI), 0.09-0.30 vs. English speakers], were foreign-born (OR, 0.31; 95% CI, 0.16-0.58 vs. U.S.-born), and had lower educational attainment (e.g., high school degree or less; OR, 0.14; 95% CI, 0.08-0.26 vs. college or higher degree). Women receiving DBN were more likely to be aware of BD (OR, 2.61; 95% CI, 1.59-4.27) but not more knowledgeable about the impact of BD on breast cancer risk and detection. However, women reporting additional communication about their BD showed greater knowledge in these areas.

CONCLUSIONS

DBN increases BD awareness disproportionately across sociodemographic groups.

IMPACT

Efforts to improve communication of DBN must focus on addressing barriers in lower socioeconomic and racially and ethnically diverse women, including educational and language barriers.

Does diagnostic mammography need to be a routine component of the initial evaluation of a breast symptom in women 30-39 years of age?

Diagnostic mammography is routinely ordered, along with targeted breast ultrasound, to evaluate breast symptoms in women 30-39 years of age. However, in this age group, mammography is often limited by breast density and the probability of detecting an occult malignancy is low. We sought to evaluate whether diagnostic mammography detected any new incidental malignancies in women aged 30-39 years presenting with focal breast symptoms. This retrospective study included women 30-39 years of age who had a diagnostic mammogram performed for focal breast symptoms at a single institution from 2002 to 2017. Descriptive analyses were performed to determine the rate of incidental mammographic findings outside of the region of the presenting symptom that 1) led to additional imaging and/or biopsies and 2) were found to be malignant. During the 16-year study period, 1770 evaluations were performed, of which 249 (14.1%) were found to have an additional incidental mammographic abnormality. Further diagnostic imaging was required in 211 (11.3%), core biopsy in 67 (3.8%), and excisional biopsy in 8 (0.5%). None of the mammographically detected incidental findings resulted in a new diagnosis of breast cancer. In the evaluation of focal benign breast symptoms in women 30-39 years of age, diagnostic mammography did not detect any new incidental malignancies outside of the area of interest, but instead led to additional unavailing imaging and biopsy procedures. The mammography component of the diagnostic evaluation of younger average-risk women may potentially be omitted if the presenting symptom is determined to be benign with ultrasound alone.

Association between radiologists' and facilities' characteristics and mammography screening detection of ductal carcinoma in situ

PURPOSE

The aim of our study was, first, to measure association between radiologists and facilities characteristics and DCIS detection. Second, to assess whether those characteristics affect differently the likelihood of detection of DCIS versus invasive breast cancer. When applicable, we examined whether the identified characteristics were similarly associated with low-grade and high-grade DCIS detection.

METHODS

This retrospective cohort study included 1,750,002 digital screening mammograms (2145 screen-detected DCIS) performed in the Quebec breast cancer screening program between 2007 and 2015 inclusively. The associations between radiologists' and facilities' characteristics and (1) the DCIS detection rate, (2) the invasive detection rate, and (3) the odds of DCIS on invasive detection were assess. For statistically significant associations in the latter analysis, analyses stratified by DCIS grade were performed. Multivariable logistic regression with generalized estimating equations estimates to account for correlation among mammograms was used.

RESULTS

Compared to radiologists with recall rate between 5.0 and 9.9%, radiologists with recall rate between 15.0-19.9% and ≥ 20% reached a higher DCIS detection rate, with adjusted detection ratios of, respectively, 1.33 (95% confidence interval = 1.15-1.53) and 1.43 (95% confidence interval = 1.13-1.81). Increase in radiologist' recall rate was statistically significantly associated with an increase in detection of low/intermediate-grade DCIS (P < 0.001), while not in high-grade DCIS (P = 0.15).

CONCLUSIONS

A major determinant of DCIS detection is the radiologists' recall rate. Abnormalities referred by radiologists with higher recall rates should be identified in order to understand how to decrease recall rate while keeping an optimal DCIS and invasive detection rate.

Impact of Breast Density Awareness on Knowledge about Breast Cancer Risk Factors and the Self-Perceived Risk of Breast Cancer

Breast density (BD) reduces sensitivity of mammography, and is a strong risk factor for breast cancer (BC). Data about women's awareness and knowledge of BD are limited. Our aim is to examine whether the BD information disclosure and BD awareness among women without BC are related to their knowledge about BC risk factors. We examined self-reported BC risk perception and its association to BD awareness and level of health literacy. A cross-sectional, single site study included 263 Croatian women without BC who had mammographic examination. Data were collected by interviews using questionnaires and a validated survey. Of the total, 77.1% had never heard of BD, and 22.9% were aware of their BD. Most participants who knew their BD (88.2%, p < 0.001) had higher levels of education. Majority of subjects (66.8%) had non-dense breasts and 33.2% had dense breasts. Subjects aware of their BD knew that post-menopausal hormone replacement therapy (p = 0.04) and higher BD (p = 0.03) are BC risk factors. They could more easily access information about health promotion (p = 0.03). High-BD informed women assessed their lifetime BC risk as significantly higher than all others (p = 0.03). Comprehension of BD awareness and knowledge is crucial for reinforcement of educational strategies and development of amendatory BC screening decisions.

Subjective Versus Quantitative Methods of Assessing Breast Density

In order to find a consistent, simple and time-efficient method of assessing mammographic breast density (MBD), different methods of assessing density comparing subjective, quantitative, semi-subjective and semi-quantitative methods were investigated. Subjective MBD of anonymized mammographic cases (n = 250) from a national breast-screening programme was rated by 49 radiologists from two countries (UK and USA) who were voluntarily recruited. Quantitatively, three measurement methods, namely VOLPARA, Hand Delineation (HD) and ImageJ (IJ) were used to calculate breast density using the same set of cases, however, for VOLPARA only mammographic cases (n = 122) with full raw digital data were included. The agreement level between methods was analysed using weighted kappa test. Agreement between UK and USA radiologists and VOLPARA varied from moderate (κw = 0.589) to substantial (κw = 0.639), respectively. The levels of agreement between USA, UK radiologists, VOLPARA with IJ were substantial (κw = 0.752, 0.768, 0.603), and with HD the levels of agreement varied from moderate to substantial (κw = 0.632, 0.680, 0.597), respectively. This study found that there is variability between subjective and objective MBD assessment methods, internationally. These results will add to the evidence base, emphasising the need for consistent, simple and time-efficient MBD assessment methods. Additionally, the quickest method to assess density is the subjective assessment, followed by VOLPARA, which is compatible with a busy clinical setting. Moreover, the use of a more limited two-scale system improves agreement levels and could help minimise any potential country bias.

Factors associated with false-positive mammography at first screen in an Asian population

Introduction

False-positive recall is an issue in national screening programmes. The aim of this study is to investigate the recall rate at first screen and to identify potential predictors of false-positive recall in a multi-ethnic Asian population-based breast cancer screening programme.

Methods

Women aged 50–64 years attending screening mammography for the first time (n = 25,318) were included in this study. The associations between potential predictors (sociodemographic, lifestyle and reproductive) and false-positive recall were evaluated using multivariable logistic regression models.

Results

The recall rate was 7.6% (n = 1,923), of which with 93.8% were false-positive. Factors independently associated with higher false-positive recall included Indian ethnicity (odds ratio [95% confidence interval]: 1.52 [1.25 to 1.84]), premenopause (1.23 [1.04 to 1.44]), nulliparity (1.85 [1.57 to 2.17]), recent breast symptoms (1.72 [1.31 to 2.23]) and history of breast lump excision (1.87 [1.53 to 2.26]). Factors associated with lower risk of false-positive recall included older age at screen (0.84 [0.73 to 0.97]) and use of oral contraceptives (0.87 [0.78 to 0.97]). After further adjustment of percent mammographic density, associations with older age at screening (0.97 [0.84 to 1.11]) and menopausal status (1.12 [0.95 to 1.32]) were attenuated and no longer significant.

Conclusion

For every breast cancer identified, 15 women without cancer were subjected to further testing. Efforts to educate Asian women on what it means to be recalled will be useful in reducing unnecessary stress and anxiety.

Patient, Radiologist, and Examination Characteristics Affecting Screening Mammography Recall Rates in a Large Academic Practice

OBJECTIVE

The aims of this study were to evaluate patient, radiologist, and examination characteristics affecting screening mammography recall rates in an academic breast imaging practice and to identify modifiable factors that could reduce recall variation.

METHODS

This institutional review board-approved retrospective study included screening mammographic examinations in female patients interpreted by 13 breast imaging specialists at an academic center and two outpatient centers from October 1, 2012, to May 31, 2015. Patient demographics were extracted via electronic medical record. Natural language processing captured breast density, BI-RADS assignment, and current and prior screening examination findings. Radiologists' annual screening volumes, clinical experience, and concentration in breast imaging were calculated. Risk aversion, stress from uncertainty, and malpractice concerns were derived via survey. Univariate and multivariate analyses assessed patient, radiologist, and examination characteristics associated with likelihood of mammography recall. The Pearson product-moment correlation coefficient was used to assess the relationship between cancer detection rate and recall rate.

RESULTS

Overall, 5,678 of 61,198 screening examinations (9.3%) were recalled. In multivariate analysis, patient and radiologist characteristics associated with higher odds of recall included patient's age < 50 years (P < .0001), prior mammographic findings (calcification [P < .0001], mass [P < .0001], higher density category [P < .0001]), baseline examination (P < .0001), annual reading volume < 1,250 examinations (P = .0282), and <10 years of experience (P = .0036). Radiologist's risk aversion, stress from uncertainty, malpractice concerns, and cancer detection rates were not associated with higher recall rates (r = -0.36, P = .23).

CONCLUSIONS

In addition to patient and examination factors, screening recall variations were associated with radiologists' annual reading volume and experience. Interventions targeting radiologist factors (screening volumes, second review of potential recalls) may help reduce unwarranted variation in screening recall.

Association between Screening Mammography Recall Rate and Interval Cancers in the UK Breast Cancer Service Screening Program: A Cohort Study

Purpose To determine whether low levels of recall lead to increased interval cancers and the magnitude of this effect. Materials and Methods The authors retrospectively analyzed prospectively collected data from the UK National Health Service Breast Screening Programme during a 36-month period (April 1, 2005 to March 31, 2008), with 3-year follow-up in women aged 50-70 years. Data on recall, cancers detected at screening, and interval cancers were available for each of the 84 breast screening units and for each year (n = 252). The association between interval cancers and recalls was modeled by using Poisson regression on aggregated data and according to age (5-year intervals) and screening type (prevalent vs incident). Results The authors analyzed 5 126 689 screening episodes, demonstrating an average recall to assessment rate (RAR) of 4.56% (range, 1.64%-8.42%; standard deviation, 1.15%), cancer detection rate of 8.1 per 1000 women screened, and interval cancer rate (ICR) of 3.1 per 1000 women screened. Overall, a significant negative association was found between RAR and ICR (Poisson regression coefficient: -0.039 [95% confidence interval: -0.062, -0.017]; P = .001), with approximately one fewer interval cancer for every additional 80-84 recalls. Subgroup analysis revealed similar negative correlations in women aged 50-54 years (P = .002), 60-64 years (P = .01), and 65-69 years (P = .008) as well as in incident screens (P = .001) and prevalent screens (P = .04). No significant relationship was found in women aged 55-59 years (P = .46). Conclusion There was a statistically significant negative correlation between RAR and ICR, which suggests the merit of a minimum threshold for RAR. © RSNA, 2018 Online supplemental material is available for this article.

Availability of prior mammograms affects incomplete report rates in mobile screening mammography

PURPOSE

Mobile mammography can improve access to screening mammography in rural areas and underserved populations. We evaluated the frequency of incomplete reports in mobile mammography screening and the relationships between prior mammograms and recall rates.

METHODS

The frequency of incomplete mammogram reports, the subgroups of those needing prior comparison mammograms, recalls for additional imaging, and availability of prior mammograms of a mobile screening mammography unit were compared with fixed site mammography from January 1, 2007 through December 31, 2009. All mobile unit mammograms were full field digital mammography (FFDM). Differences between rates of recall, incomplete reports, and availability of prior mammograms were calculated using the Chi-Square statistic.

RESULTS

Of 2640 mobile mammography cases, 21.9% (578) reports were incomplete, versus 15.2% (7653) (p ≤ 0.001) of 50325 fixed site reports. Of incomplete cases, recall for additional imaging occurred among 8.3% (218) of mobile mammography reports versus 11.3% (5708) (p ≤ 0.001) of fixed site reports. Prior mammograms were needed among 13.6% (360) of mobile mammography versus 3.9% (1945) (p ≤ 0.001) of fixed site reports. Mobile mammography recall rate varied with availability of prior mammograms: 16.0% (54) when no prior mammograms, 7.6% (127) when prior mammograms were elsewhere but unavailable and 5.9% (37) when prior FFDM were immediately available (p ≤ 0.001).

CONCLUSIONS

Incomplete reports were more frequent in mobile mammography than the fixed site. The availability of prior comparison mammograms at time of interpretation decreased the rate of incomplete mammogram reports. Recall rates were higher without prior comparison mammograms and lowest when comparison FFDM mammograms were available.

Assessing the Recall Rate for Screening Mammography: Comparing the Medicare Hospital Compare Dataset With the National Mammography Database

OBJECTIVE

High-quality screening mammography has been shown to substantially reduce mortality from breast cancer. Recall rate is a principal performance metric for screening mammography because it directly relates to the rate of false-positive examinations. This study aims to compare the recall rate derived using two sources-the claims-based Hospital Compare (HC) dataset from the Centers for Medicare & Medicaid Services versus the National Mammography Database (NMD) from the American College of Radiology-to understand the implications in pay-for-performance and quality improvement activities.

MATERIALS AND METHODS

This study retrospectively compared the recall rate reported by NMD facilities with that reported in the HC dataset. Site matching was performed by facility name and zip code, followed by manual verification. Scatterplots, correlations, a paired t test, and Bland-Altman analysis were performed to assess association between the two measures.

RESULTS

During the period from October 1 to December 1, 2016, 92 facilities were unambiguously matched using 2014-2015 records in both datasets. The recall rates were positively correlated (r = 0.428, p < 0.001), but the mean HC recall rate (8.5% ± 2.86% [SD]) was significantly (p < 0.001) lower than the mean NMD recall rate (10.6% ± 3.90%).

CONCLUSION

The NMD and HC are two commonly used datasets for measuring screening mammography recall rate. Although recall rates are correlated at the individual facility level, there are important differences that have implications for quality improvement and pay-for-performance.

The Reproducibility of Changes in Diagnostic Figures of Merit Across Laboratory and Clinical Imaging Reader Studies

RATIONALE AND OBJECTIVES

In this paper we examine which comparisons of reading performance between diagnostic imaging systems made in controlled retrospective laboratory studies may be representative of what we observe in later clinical studies. The change in a meaningful diagnostic figure of merit between two diagnostic modalities should be qualitatively or quantitatively comparable across all kinds of studies.

MATERIALS AND METHODS

In this meta-study we examine the reproducibility of relative measures of sensitivity, false positive fraction (FPF), area under the receiver operating characteristic (ROC) curve, and expected utility across laboratory and observational clinical studies for several different breast imaging modalities, including screen film mammography, digital mammography, breast tomosynthesis, and ultrasound.

RESULTS

Across studies of all types, the changes in the FPFs yielded very small probabilities of having a common mean value. The probabilities of relative sensitivity being the same across ultrasound and tomosynthesis studies were low. No evidence was found for different mean values of relative area under the ROC curve or relative expected utility within any of the study sets.

CONCLUSION

The comparison demonstrates that the ratios of areas under the ROC curve and expected utilities are reproducible across laboratory and clinical studies, whereas sensitivity and FPF are not.

The Long-Term Effectiveness and Cost Effectiveness of Organized versus Opportunistic Screening for Breast Cancer in Austria

BACKGROUND

In 2014, Austrian health authorities implemented an organized breast cancer screening program. Until then, there has been a long-standing tradition of opportunistic screening.

OBJECTIVES

To evaluate the cost-effectiveness of organized screening compared with opportunistic screening, as well as to identify factors influencing the clinical and economic outcomes.

METHODS

We developed and validated an individual-level state-transition model and assessed the health outcomes and costs of organized and opportunistic screening for 40-year-old asymptomatic women. The base-case analysis compared a scenario involving organized biennial screening with a scenario reflecting opportunistic screening practice for an average-risk woman aged 45 to 69 years. We applied an annual discount rate of 3% and estimated the incremental cost-effectiveness ratio in terms of the cost (2012 euros) per life-year gained (LYG) from a health care perspective. Deterministic and probabilistic sensitivity analyses were performed to assess uncertainty.

RESULTS

Compared with opportunistic screening, an organized program yielded on average additional 0.0118 undiscounted life-years (i.e., 4.3 days) and cost savings of €41 per woman. In the base-case analysis, the incremental cost-effectiveness ratio of organized screening was approximately €20,000 per LYG compared with no screening. Assuming a willingness-to-pay threshold of €50,000 per LYG, there was a 70% probability that organized screening would be considered cost-effective. The attendance rate, but not the test accuracy of mammography, was an influential factor for the cost-effectiveness.

CONCLUSIONS

The decision to adopt organized screening is likely an efficient use of limited health care resources in Austria.

Simplifying Breast Imaging Reporting and Data System classification of mammograms with pure suspicious calcifications

Objectives

To investigate the risk of malignancy following stereotactic breast biopsy of calcifications classified as Breast Imaging Reporting and Data System (BI-RADS) 3, 4, and 5.

Methods

The study included women with pure calcifications (not associated with masses or architectural distortions) who underwent stereotactic breast biopsy at the Dutch Cancer Institute between January 2011 and October 2013. Suspicious calcifications (Breast Imaging Reporting and Data System 3, 4, or 5) detected on mammography were biopsied. All lesions were assessed by breast radiologists and classified according to the BI-RADS lexicon.

Results

Overall, 473 patients underwent 497 stereotactic breast biopsies. Sixty-six percent (326/497) of calcifications were classified B4, 30% (148/497) B3, and 4% (23/497) B5. Of the 226 (45%) malignant lesions, there were 182 pure ductal carcinoma in situ, 22 mixed ductal carcinoma in situ and invasive carcinomas (ductal or lobular), 21 pure invasive carcinomas, and one angiosarcoma. Malignancy was found in 32% (95% confidence interval [CI] 0.24 to 0.39) of B3, 49% (95% CI 0.43 to 0.54) of B4, and 83% (95% CI 0.61 to 0.95) of B5 calcifications.

Conclusions

Considering the high predictive value for malignancy in B3 calcifications, we propose that these lesions should be classified as suspicious (B4), especially in a screening setting.

Qualitative Versus Quantitative Mammographic Breast Density Assessment: Applications for the US and Abroad

Mammographic breast density (MBD) has been proven to be an important risk factor for breast cancer and an important determinant of mammographic screening performance. The measurement of density has changed dramatically since its inception. Initial qualitative measurement methods have been found to have limited consistency between readers, and in regards to breast cancer risk. Following the introduction of full-field digital mammography, more sophisticated measurement methodology is now possible. Automated computer-based density measurements can provide consistent, reproducible, and objective results. In this review paper, we describe various methods currently available to assess MBD, and provide a discussion on the clinical utility of such methods for breast cancer screening.

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.

Recall Rate Reduction with Tomosynthesis During Baseline Screening Examinations: An Assessment From a Prospective Trial

RATIONALE AND OBJECTIVES

Assess results of a prospective, single-site clinical study evaluating digital breast tomosynthesis (DBT) during baseline screening mammography.

MATERIALS AND METHODS

Under an institutional review board-approved Health Insurance Portability and Accountability Act (HIPAA)-compliant protocol, consenting women between ages 34 and 56 years scheduled for their initial and/or baseline screening mammogram underwent both full field digital mammography (FFDM) and DBT. The FFDM and the FFDM plus DBT images were interpreted independently in a reader by mode balanced approach by two of 14 participating radiologists. A woman was recalled for a diagnostic work-up if either radiologist recommended a recall. We report overall recall rates and related diagnostic outcome from the 1080 participants. Proportion of recommended recalls (Breast Imaging Reporting and Data System 0) were compared using a generalized linear mixed model (SAS 9.3) with a significance level of P = .0294.

RESULTS

The fraction of women without breast cancer recommended for recall using FFDM alone and FFDM plus DBT were 412 of 1074 (38.4%) and 274 of 1074 (25.5%), respectively (P < .001). Large inter-reader variability in terms of recall reduction was observed among the 14 readers; however, 11 of 14 readers recalled fewer women using FFDM plus DBT (5 with P < .015). Six cancers (four ductal carcinomas in situ [DCIS] and two invasive ductal carcinomas [IDC]) were detected. One IDC was detected only on DBT and one DCIS cancer was detected only on FFDM, whereas the remaining cancers were detected on both modalities.

CONCLUSIONS

The use of FFDM plus DBT resulted in a significant decrease in recall rates during baseline screening mammography with no reduction in sensitivity.

Screening for breast cancer with Breast-CT in a ProHTA simulation

Aims: The potential of dedicated Breast-CT is evaluated by simulating its impact onto the performance of the German breast cancer screening program. Attendance rates, cancer detection and economic implications are quantified. Methods: Based on a prospective health technology assessment approach, we simulated screening in different scenarios. Results: In the simulation, attendance rates increase from 54 to up to 72% due to reduced pain. Breast cancers will be detected earlier while nodal positives and distant recurrences decrease. Assuming no additional cost, cost savings of up to €55 million in one screening period are computed. Conclusion: The simulation indicates that earlier cancer detection, fewer unnecessary biopsies and less pain are potential benefits of Breast-CT resulting in cost savings and higher attendance.

2D mammography, digital breast tomosynthesis, and ultrasound: which should be used for the different breast densities in breast cancer screening?

PURPOSE

To determine which modalities [2D mammography (2D), digital breast tomosynthesis (DBT), whole breast sonography (WBS)] are optimal for screening depending on breast density.

METHODS

Institutional retrospective cohort study of 2013 screening mammograms (16,789), sorted by modalities and density.

RESULTS

Cancer detection is increased by adding WBS to 2D (P=.02) for the overall study population. Recall rate was lowest with 2D+DBT (10.2%, P<.001) and highest with 2D+DBT+WBS (23.6%, P<.001) for the overall study population as well.

CONCLUSION

Women with dense and nondense breasts benefit from reduced recall rate with the addition of DBT; however, this benefit is negated with the addition of WBS.

Geographic variation in volumetric breast density between screening regions in the Netherlands

OBJECTIVES

Differences in breast density between populations may explain part of the variation in regional breast cancer screening performance. This study aimed to determine whether regional differences in breast density distribution are present in the Dutch screening population.

METHODS

As part of the DENSE trial, mammographic density was measured using a fully-automated volumetric method. The regions in our study were based on the geographic coverage of 14 reading units representing a large part of the Netherlands. General linear models were used.

RESULTS

Four hundred eighty-five thousand and twenty-one screening participants with a median age of 60 years were included (2013-2014). The proportion of women with heterogeneously or extremely dense breasts ranged from 32.5% to 45.7% between regions. Mean percent dense volume varied between 6.51% (95% confidence interval [CI]: 6.46-6.55) and 7.68% (95% CI: 7.66-7.71). Age differences could not explain the variation. Socio-economic status (SES) was positively associated with volumetric density in all analyses (low SES: 6.95% vs. high SES: 7.63%; p trend  < 0.0001), whereas a potential association between urbanisation and breast density only became apparent after SES adjustment.

CONCLUSION

There appears to be geographic variation in mammographic density in the Netherlands, emphasizing the importance of including breast density as parameter in the evaluation of screening performance.

KEY POINTS

• Mammographic density may affect regional breast cancer screening performance. • Volumetric breast density varies across screening areas. • SES is positively associated with breast density. • Implications of volumetric breast density differences need to be studied further.

Awareness of breast density and its impact on breast cancer detection and risk

PURPOSE

Legislation mandating disclosure of breast density (BD) information has passed in 21 states; however, actual awareness of BD and knowledge of its impact on breast cancer detection and risk are unknown.

METHODS

We conducted a national cross-sectional survey administered in English and Spanish using a probability-based sample of screening-age women, with oversampling of Connecticut, the only state with BD legislation in effect for > 1 year before the survey.

RESULTS

Of 2,311 women surveyed, 65% responded. Overall, 58% of women had heard of BD, 49% knew that BD affects breast cancer detection, and 53% knew that BD affects cancer risk. After multivariable adjustment, increased BD awareness was associated with white non-Hispanic race/ethnicity (Hispanic v white non-Hispanic: odds ratio [OR], 0.23; P < .001), household income (OR, 1.07 per category increase; P < .001), education (OR, 1.19 per category increase; P < .001), diagnostic evaluation after a mammogram (OR, 2.64; P < .001), and postmenopausal hormone therapy (OR, 1.69; P = .002). Knowledge of the masking effect of BD was associated with higher household income (OR, 1.10; P < .001), education (OR, 1.22; P = .01), prior breast biopsy (OR, 2.16; P < .001), and residing in Connecticut (Connecticut v other states: OR, 3.82; P = .003). Connecticut residents were also more likely to have discussed their BD with a health care provider (67% v 43% for residents of other US states; P = .001).

CONCLUSION

Disparities in BD awareness and knowledge exist by race/ethnicity, education, and income. BD legislation seems to be effective in increasing knowledge of BD impact on breast cancer detection. These findings support continued and targeted efforts to improve BD awareness and knowledge among women eligible for screening mammography.

Performance of digital screening mammography among older women in the United States

BACKGROUND

Although healthy women aged 65 years have a life expectancy of 20 years, there is a paucity of data on the performance of digital screening mammography among these women. The authors examined the performance and outcomes of digital screening mammography among a national group of women aged ≥65 years.

METHODS

From Breast Cancer Surveillance Consortium data for the years 2005 to 2011, the authors included 296,496 full-field digital screening mammograms among 133,042 women ages ≥65 years without a history of breast cancer. Sensitivity, specificity, positive predictive value (PPV1 ), recall rates, and 95% confidence intervals (95% CIs) were calculated across the spectrum of age and breast density. Multivariate logistic regression was used to compare mammography accuracy, cancer-detection rates (CDRs), and tumor characteristics by age and breast density.

RESULTS

Multivariate analyses revealed a significant decrease in the recall rate with age (P for linear trend [Ptrend ] < .001) and significant increases in specificity, PPV1 , and CDR with age (Ptrend  < .001, Ptrend  < .001, and Ptrend  = .01, respectively). Sensitivity did not vary significantly with age. Among women with cancer, the proportion with invasive disease increased with age from 76% at ages 65 to 74 years to 81% at ages ≥80 years. There was a higher proportion of late stage cancers and positive lymph nodes among women ages 65 to 74 years compared with women in the older age groups.

CONCLUSIONS

The specificity, PPV1 , recall rate, and CDR of digital screening mammography improved with increased age. In addition, as age increased, the proportion of women with invasive versus ductal carcinoma in situ rose, whereas the proportion of women with positive lymph nodes decreased.

Pursuing optimal thresholds to recommend breast biopsy by quantifying the value of tomosynthesis

A 2% threshold has been traditionally used to recommend breast biopsy in mammography. We aim to characterize how the biopsy threshold varies to achieve the maximum expected utility (MEU) of tomosynthesis for breast cancer diagnosis. A cohort of 312 patients, imaged with standard full field digital mammography (FFDM) and digital breast tomosynthesis (DBT), was selected for a reader study. Fifteen readers interpreted each patient's images and estimated the probability of malignancy using two modes: FFDM versus FFDM + DBT. We generated receiver operator characteristic (ROC) curves with the probabilities for all readers combined. We found that FFDM+DBT provided improved accuracy and MEU compared with FFDM alone. When DBT was included in the diagnosis along with FFDM, the optimal biopsy threshold increased to 2.7% as compared with the 2% threshold for FFDM alone. While understanding the optimal threshold from a decision analytic standpoint will not help physicians improve their performance without additional guidance (e.g. decision support to reinforce this threshold), the discovery of this level does demonstrate the potential clinical improvements attainable with DBT. Specifically, DBT has the potential to lead to substantial improvements in breast cancer diagnosis since it could reduce the number of patients recommended for biopsy while preserving the maximal expected utility.

Addressing the challenge of assessing physician-level screening performance: mammography as an example

Background

Motivated by the challenges in assessing physician-level cancer screening performance and the negative impact of misclassification, we propose a method (using mammography as an example) that enables confident assertion of adequate or inadequate performance or alternatively recognizes when more data is required.

Methods

Using established metrics for mammography screening performance–cancer detection rate (CDR) and recall rate (RR)–and observed benchmarks from the Breast Cancer Surveillance Consortium (BCSC), we calculate the minimum volume required to be 95% confident that a physician is performing at or above benchmark thresholds. We graphically display the minimum observed CDR and RR values required to confidently assert adequate performance over a range of interpretive volumes. We use a prospectively collected database of consecutive mammograms from a clinical screening program outside the BCSC to illustrate how this method classifies individual physician performance as volume accrues.

Results

Our analysis reveals that an annual interpretive volume of 2770 screening mammograms, above the United States’ (US) mandatory (480) and average (1777) annual volumes but below England’s mandatory (5000) annual volume is necessary to confidently assert that a physician performed adequately. In our analyzed US practice, a single year of data uniformly allowed confident assertion of adequate performance in terms of RR but not CDR, which required aggregation of data across more than one year.

Conclusion

For individual physician quality assessment in cancer screening programs that target low incidence populations, considering imprecision in observed performance metrics due to small numbers of patients with cancer is important.

Beyond the mammography quality standards act: measuring the quality of breast cancer screening programs

OBJECTIVE

A high-quality screening mammography program should find breast cancer when it exists and when the lesion is small and ensure that suspicious findings receive prompt follow-up. The Mammography Quality Standards Act (MQSA) guidelines related to tracking outcomes are insufficient for assessing quality of care. We used data from a quality improvement project to determine whether screening mammography facilities could show that they met certain quality benchmarks beyond those required by MQSA.

MATERIALS AND METHODS

Participating facilities provided aggregate data on screening mammography examinations performed in calendar year 2009 and corresponding diagnostic follow-up, including patients lost to follow-up, timing of diagnostic imaging and biopsy, cancer detection rates, and the proportion of cases of cancer detected as minimal and early-stage tumors.

RESULTS

Among the 52 participating institutions, the percentage of institutions meeting each benchmark varied from 27% to 83%. Facilities with American College of Surgeons or National Consortium of Breast Centers designation were more likely to meet benchmarks pertaining to cancer detection and early detection, and disproportionate share facilities were less likely to meet benchmarks pertaining to timeliness of care.

CONCLUSION

The results suggest a combination of quality of care issues and incomplete tracking of patients. To accurately measure the quality of the breast cancer screening process, it is critical that there be complete tracking of patients with abnormal screening mammography findings so that results can be interpreted solely in terms of quality of care. The MQSA guidelines for tracking outcomes and measuring quality indicators should be strengthened for better assessment of quality of care.

CAD May Not be Necessary for Microcalcifications in the Digital era, CAD May Benefit Radiologists for Masses

Objective:

The aim of this study was to evaluate the effectiveness of computer-aided detection (CAD) to mark the cancer on digital mammograms at the time of breast cancer diagnosis and also review retrospectively whether CAD marked the cancer if visible on any available prior mammograms, thus potentially identifying breast cancer at an earlier stage. We sought to determine why breast lesions may or may not be marked by CAD. In particular, we analyzed factors such as breast density, mammographic views, and lesion characteristics.

Materials and Methods:

Retrospective review from 2004 to 2008 revealed 3445 diagnosed breast cancers in both symptomatic and asymptomatic patients; 1293 of these were imaged with full field digital mammography (FFDM). After cancer diagnosis, in a retrospective review held by the radiologist staff, 43 of these cancers were found to be visible on prior-year mammograms (false-negative cases); these breast cancer cases are the basis of this analysis. All cases had CAD evaluation available at the time of cancer diagnosis and on prior mammography studies. Data collected included patient demographics, breast density, palpability, lesion type, mammographic size, CAD marks on current- and prior-year mammograms, needle biopsy method, pathology results (core needle and/or surgical), surgery type, and lesion size.

Results:

On retrospective review of the mammograms by the staff radiologists, 43 cancers were discovered to be visible on prior-year mammograms. All 43 cancers were masses (mass classification included mass, mass with calcification, and mass with architectural distortion); no pure microcalcifications were identified in this cohort. Mammograms with CAD applied at the time of breast cancer diagnosis were able to detect 79% (34/43) of the cases and 56% (24/43) from mammograms with CAD applied during prior year(s). In heterogeneously dense/extremely dense tissue, CAD marked 79% (27/34) on mammograms taken at the time of diagnosis and 56% (19/34) on mammograms with CAD applied during the prior year(s). At time of diagnosis, CAD marked lesions in 32% (11/34) on the craniocaudal (CC) view, 21% (7/34) on the mediolateral oblique (MLO) view. Lesion size of those marked by CAD or not marked were similar, the average being 15 and 12 mm, respectively.

Conclusion:

CAD marked cancers on mammograms at the time of diagnosis in 79% of the cases and in 56% of the cases from the mammograms with CAD applied in the prior year(s). Our review demonstrated that CAD can mark invasive breast carcinomas in even dense breast tissue. CAD marked a significant portion on the CC view only, which may be an indicator to radiologists to be especially vigilant when a lesion is marked on this view.

Characteristics and screening outcome of women referred twice at screening mammography

OBJECTIVES

To determine the characteristics and screening outcome of women referred twice at screening mammography.

METHODS

We included 424,703 consecutive screening mammograms and collected imaging, biopsy and surgery reports of women with screen-detected breast cancer. Review of screening mammograms was performed to determine whether or not an initial and second referral comprised the same lesion.

RESULTS

The overall positive predictive value of referral for cancer was 38.6% (95% CI 37.3-39.8%). Of 147 (2.6%) women referred twice, 86 had been referred for a different lesion at second referral and 32 of these proved malignant (37.2%, 95% CI 27.0-47.4%). Sixty-one women had been referred twice for the same lesion, of which 22 proved malignant (36.1%, 95% CI 24.1-48.0%). Characteristics of these women were comparable to women with cancer diagnosed after first referral. Compared with women without cancer at second referral for the same lesion, women with cancer more frequently showed suspicious densities at screening mammography (86.4% vs 53.8%, P = 0.02) and work-up at first referral had less frequently included biopsy (22.7% vs 61.5%, P = 0.004).

CONCLUSIONS

Cancer risk in women referred twice for the same lesion is similar to that observed in women referred once, or referred for a second time but for a different lesion.

KEY POINTS

Cancer risk was 36% for lesions referred twice at screening mammography. The cancer risk was similar for lesions referred only once at screening. Densities at first referral were associated with increased cancer risk at second referral. No biopsy at first referral was associated with increased cancer risk at second referral. Patient and tumour characteristics were similar for women with and without diagnostic delay.

Should breast cancer survivors be excluded from, or invited to, organised mammography screening programmes?

BACKGROUND

The prevalence of breast cancer in developed countries has steadily risen over recent decades. Immediate and long-term health needs of patients, including preventive care and screening services, are receiving increasing attention. A question still unresolved is whether breast cancer survivors should receive mammographic surveillance in the clinical or screening setting and, thus, whether they should be excluded from, or invited to, organised mammography screening programmes. The objective of this article is to discuss the many contradictory aspects of this matter.

DISCUSSION

Problems with mammographic surveillance of breast cancer survivors include: weak evidence of a reduction in mortality; lack of evidence in favour of one setting or the other; lack of evidence-based guidelines for the frequency and duration of surveillance; disproportionate emphasis placed on the first few years post-treatment, probably dictated by surgical and oncological priorities; a variety of screening policies, as these women are permanently or temporarily or partially excluded from many - but not all - organised screening programmes worldwide; an even greater disparity in follow-up protocols used in the clinical setting; a paucity of data on compliance to mammographic surveillance in both settings; and a difficulty in coordinating the roles of health care providers. In the future, the use of mammography in breast cancer survivors will be influenced by the inclusion of women aged > 69 years in organised screening programmes and the implementation of multidisciplinary breast units, and will probably be investigated by research activities on individual risk assessment and risk-tailored screening. In the interim, current problems can be partially alleviated with some technical solutions in screening data recording, patient flows, and care coordination.

SUMMARY

Mammographic surveillance of breast cancer survivors is situated at the crossroads of numerous different specialist areas of breast cancer control and management. The solutions for current problems probably lie in some important modifications in the conventional screening procedure that are underway or under study. These developments appear to be directed towards a partial modification of the screening rationale, with an adaptation to meet the diversified breast care needs of women. The complexity of the matter constitutes a call to action for several entities to eliminate the barriers to effective research in this field.

Radiographic findings after breast augmentation by autologous fat transfer

BACKGROUND

Fat transfer to healthy breasts, that is, in women with no history of breast disease, particularly breast cancer, is becoming increasingly popular. The main issue remains whether the transfer of fat cells to the native breast hampers breast imaging. This pilot study aimed to assess the effectiveness of radiographic evaluation after breast lipomodeling and to propose objective elements for the detection of mammographic signs, and for postoperative evaluation of breast density and Breast Imaging Reporting and Data System (American College of Radiology) classification.

METHODS

The authors retrospectively reviewed the radiographic findings of patients undergoing breast lipomodeling between 2000 and 2008. A descriptive semiologic analysis was conducted. Then, the authors compared breast tissue density and Breast Imaging Reporting and Data System categorization in 20 patients with preoperative and postoperative images available for review.

RESULTS

The descriptive analysis identified 16 percent of mammograms with microcalcifications, 9 percent with macrocalcifications, 25 percent with clear well-focused images of cystic lesions, and 12 percent with tissue remodeling. The comparative study showed no statistically significant difference between breast density findings before and after fat injection, whether using the American College of Radiology classification or a personalized rating system. Similarly, no significant difference was observed using the American College of Radiology Breast Imaging Reporting and Data System categorization before and after fat grafting.

CONCLUSIONS

Radiographic follow-up of breasts treated with fat grafting is not problematic and should not be a hindrance to the procedure. However, the authors' preliminary results should be confirmed in larger series, and the radiographic follow-up of women undergoing breast lipomodeling should be standardized to ensure reproducibility and improve patient safety.

Dedicated breast computed tomography: the optimal cross-sectional imaging solution?

Dedicated breast computed tomography (DBCT) is a burgeoning technology that has many advantages over current breast-imaging systems. Three-dimensional visualization of the breast mitigates the limiting effects of superimposition noted with mammography. Postprocessing capabilities will allow application of advanced technologies, such as creation of maximum-intensity projection and subtraction images, and the use of both computer-aided detection and possible computer-aided diagnosis algorithms. Excellent morphologic detail and soft tissue contrast can be achieved, due in part to the isotropic image data that DBCT produces. The expected cost should be more reasonable than magnetic resonance imaging. At present, because the breast is not compressed, patients find it more comfortable than mammography. Physiologic information can be obtained when intravenous contrast material is used and/or when DBCT is combined with single photon emission-computed tomography or positron emission tomography. DBCT provides an excellent platform for multimodality systems including integration with interventional and therapeutic procedures. With a slightly altered design, the DBCT platform may also be useful for external-beam radiation with image guidance.

Best ways to provide feedback to radiologists on mammography performance

OBJECTIVE

The Mammography Quality Standards Act of 1992 required a minimum performance audit of radiologists performing mammography. Since then, no studies have evaluated radiologists' perceptions of their audit reports, such as which performance measures are the most or least useful, or what the best formats are to present performance data.

MATERIALS AND METHODS

We conducted a qualitative study with focus groups and interviews of 25 radiologists currently practicing mammography. All radiologists practiced at one of three sites in the Breast Cancer Surveillance Consortium (BCSC). The discussion guide included open-ended questions to elicit opinions on the following subjects: the most useful performance outcome measures, examples of reports and formats that are easiest to understand (e.g., graphs or tables), thoughts about comparisons between individual-level and aggregate data, and ideas about additional performance measures they would find useful. All discussions were tape-recorded and transcribed. We developed a set of themes and used ethnographic software to qualitatively analyze and extract quotes from transcripts.

RESULTS

Radiologists thought that almost all performance measures were useful. They particularly liked seeing individual data presented in graphic form with a national benchmark or guideline for each performance measure clearly marked on the graph. They appreciated comparisons between their individual data and their peers' data (within their facility or state) and requested comparisons with national data (such as the BCSC). Many thought customizable, Web-based reports would be useful.

CONCLUSION

Radiologists think that most audit statistics are useful; however, presenting performance data graphically with clear benchmarks may make them easier to understand.

Do the results of the process indicators in the Norwegian Breast Cancer Screening Program predict future mortality reduction from breast cancer?

Continuous emphases of quality control are required to achieve reduction in mortality from breast cancer as a consequence of breast cancer screening. Results of the process indicators in the first 6 years in 4 counties in the Norwegian Breast Cancer Screening Program are evaluated and will be presented. Data from women who had their initial (n = 173402) and subsequent (n = 220 058) screening provide the basis for the analysis. The breast cancer detection ratio was 3.2 the expected incidence (based on the incidence before the screening started, 1991-1995) among the initially screened women, decreasing to 2.3 among the subsequently screened. The ratio of interval cancer among the initially screened was 0.25 and 0.72 of the expected incidence, 0-12 and 13-23 months after screening, respectively. For those subsequently screened the proportions were 0.22 and 0.64, respectively. More than 50% of the invasive tumors were less than 15 mm in size, and more than 75% were lymph node negative, among both the initially and subsequently screened. The process indicators achieved in the NBCSP are promising as regards future mortality reduction. The incidence of interval cancer 13-24 months after screening is higher than recommended in the European guidelines.

[Sensitivity and specificity of the breast screening program in the Isere region based on positive results between 1991 and 1999]

PURPOSE

The screening program guidelines specify that the call back rate of women for additional imaging (positive mammogram) should not exceed 7% at initial screening, and 5% at subsequent screening. Materials and methods. Results in the Isere region (12%) have prompted a review of the correlation between the call back rate and indicators of quality (detection rate, sensitivity, specificity, positive predictive value) for the radiologists providing interpretations during that time period.

RESULTS

Three groups of radiologists were identified: the group with call back rate of 10% achieved the best results (sensitivity: 92%, detection rate: 0.53%, specificity: 90%). The group with lowest call back rate (7.7%) showed insufficient sensitivity (58%). The last group with call back rate of 18.3%, showed no improvement in sensitivity (82%) and detection rate (0.53%), but showed reduced specificity (82%).

CONCLUSION

The protocol update in 2001 does not resolve this problematic situation and national results continue to demonstrate a high percentage of positive screening mammograms. A significant increase in the number of positive screening examinations compared to recommended guidelines is not advantageous and leads to an overall decrease in the quality of the screening.

Inter-observer variability in mammography screening and effect of type and number of readers on screening outcome

We prospectively determined the variability in radiologists' interpretation of screening mammograms and assessed the influence of type and number of readers on screening outcome. Twenty-one screening mammography radiographers and eight screening radiologists participated. A total of 106 093 screening mammograms were double-read by two radiographers and, in turn, by two radiologists. Initially, radiologists were blinded to the referral opinion of the radiographers. A woman was referred if she was considered positive at radiologist double-reading with consensus interpretation or referred after radiologist review of positive cases at radiographer double-reading. During 2-year follow-up, clinical data, breast imaging reports, biopsy results and breast surgery reports were collected of all women with a positive screening result from any reader. Single radiologist reading (I) resulted in a mean cancer detection rate of 4.64 per 1000 screens (95% confidence intervals (CI)=4.23–5.05) with individual variations from 3.44 (95% CI=2.30–4.58) to 5.04 (95% CI=3.81–6.27), and a sensitivity of 63.9% (95% CI=60.5–67.3), ranging from 51.5% (95% CI=39.6–63.3) to 75.0% (95% CI=65.3–84.7). Sensitivity at non-blinded, radiologist double-reading (II), radiologist double-reading followed by radiologist review of positive cases at radiographer double-reading (III), triple reading by one radiologist and two radiographers with referral of all positive readings (IV) and quadruple reading by two radiologists and two radiographers with referral of all positive readings (V) were as follows: 68.6% (95% CI=65.3–71.9) (II); 73.2% (95% CI=70.1–76.4) (III); 75.2% (95% CI=72.1–78.2) (IV), and 76.9% (95% CI=73.9–79.9) (V). We conclude that screener performance significantly varied at single-reading. Double-reading increased sensitivity by a relative 7.3%. When there is a shortage of screening radiologists, triple reading by one radiologist and two radiographers may replace radiologist double-reading.

Cost-effectiveness analysis of mammography and clinical breast examination strategies: a comparison with current guidelines

PURPOSE

Breast cancer screening by mammography and clinical breast exam are commonly used for early tumor detection. Previous cost-effectiveness studies considered mammography alone or did not account for all relevant costs. In this study, we assessed the cost-effectiveness of screening schedules recommended by three major cancer organizations and compared them with alternative strategies. We considered costs of screening examinations, subsequent work-up, biopsy, and treatment interventions after diagnosis.

METHODS

We used a microsimulation model to generate women's life histories, and assessed screening and treatment effects on survival. Using statistical models, we accounted for age-specific incidence, preclinical disease duration, and age-specific sensitivity and specificity for each screening modality. The outcomes of interest were quality-adjusted life years (QALY) saved and total costs with a 3% annual discount rate. Incremental cost-effectiveness ratios were used to compare strategies. Sensitivity analyses were done by varying some of the assumptions.

RESULTS

Compared with guidelines from the National Cancer Institute and the U.S. Preventive Services Task Force, alternative strategies were more efficient. Mammography and clinical breast exam in alternating years from ages 40 to 79 years was a cost-effective alternative compared with the guidelines, costing $35,500 per QALY saved compared with no screening. The American Cancer Society guideline was the most effective and the most expensive, costing over $680,000 for an added QALY compared with the above alternative.

CONCLUSION

Screening strategies with lower costs and benefits comparable with those currently recommended should be considered for implementation in practice and for future guidelines.