Population-based mammography screening: comparison of screen-film and full-field digital mammography with soft-copy reading--Oslo I study

PURPOSE: To compare screen-film and full-field digital mammography with soft-copy reading in a population-based screening program. MATERIALS AND METHODS: Full-field digital and screen-film mammography were performed in 3,683 women aged 50-69 years. Two standard views of each breast were acquired with each modality. Images underwent independent double reading with use of a five-point rating scale for probability of cancer. Recall rates and positive predictive values were calculated. Cancer detection rates determined with both modalities were compared by using the McNemar test for paired proportions. Retrospective side-by-side analysis for conspicuity of cancers was performed by an external independent radiologist group with experience in both modalities. RESULTS: In 3,683 cases, 31 cancers were detected. Screen-film mammography depicted 28 (0.76%) malignancies, and full-field digital mammography depicted 23 (0.62%) malignancies. The difference between cancer detection rates was not significant (P =.23). The recall rate for full-field digital mammography (4.6%; 168 of 3,683 cases) was slightly higher than that for screen-film mammography (3.5%; 128 of 3,683 cases). The positive predictive value based on needle biopsy results was 46% for screen-film mammography and 39% for full-field digital mammography. Side-by-side image comparison for cancer conspicuity led to classification of 19 cancers as equal for probability of malignancy, six cancers as slightly better demonstrated at screen-film mammography, and six cancers as slightly better demonstrated at full-field digital mammography. CONCLUSION: There was no statistically significant difference in cancer detection rate between screen-film and full-field digital mammography. Cancer conspicuity was equal with both modalities. Full-field digital mammography with soft-copy reading is comparable to screen-film mammography in population-based screening.     

Contrast mammography in clinical practice: Current uses and potential diagnostic dilemmas

ObjectiveThis article will discuss the indications for Contrast Enhanced Spectral Mammography (CESM) with a focus on imaging interpretation including diagnostic dilemmas and pitfalls which may be encountered in practice.ConclusionUnderstanding potential diagnostic dilemmas and pitfalls of CESM allows for enhanced interpretation.The clinical utilization of Contrast Enhanced Spectral Mammography (CESM) has increased significantly over the last few years. CESM demonstrates comparable sensitivity and accuracy to magnetic resonance imaging (MRI) for the evaluation of breast cancer but is less time consuming and less expensive. Because of this, CESM is now being used in lieu of MRI for many diagnostic indicators including the evaluation of abnormal mammographic findings, extent of disease, and response to neoadjuvant therapy. Additionally, ongoing research into the role of CESM in asymptomatic screening for breast cancer is evolving. As this technique becomes more popular, focusing on appropriate technique and interpretation is important. This article reviews the current and potential roles of CESM. It provides examples of CESM utilized for diagnostic indications while highlighting diagnostic dilemmas, pitfalls, and artifacts that may be encountered when interpreting CESM images.     

CT screening for lung cancer: prevalence and incidence of mediastinal masses

PURPOSE: To determine the frequency and natural course of mediastinal masses in asymptomatic people at high risk for lung cancer who were undergoing computed tomographic (CT) screening. MATERIALS AND METHODS: Informed consent and institutional review board approval for this HIPAA-compliant study were obtained at each participating institution. All documented mediastinal masses among the 9263 baseline and 11 126 annual repeat screenings performed in the Early Lung Cancer Action Project (ELCAP) and its successor project, the New York ELCAP, were identified. Two radiologists confirmed all cases, identified the location and measured the diameter (average of length and width) of each mass, and reviewed all subsequent CT and clinical and surgical results. The prevalence and incidence of mediastinal masses were then determined. RESULTS: Of the 9263 individuals, 71 had a mediastinal mass seen at baseline screening (prevalence of 0.77%). Of the 71 masses, 41 were thymic, 16 were thyroidal, two were esophageal cancers, six were tracheal-esophageal diverticula, and six were other masses. Among the 11 126 annual repeat screenings, only one new mediastinal mass was identified (incidence of 0.01%). This suggests a long average duration for mediastinal masses in asymptomatic people. Among the 41 thymic masses, five were larger than 3.0 cm in diameter, and all five were resected; of these five, one was a thymic carcinoma and four were noninvasive thymomas. Of the remaining 36 thymic masses, 25 were evaluated at follow-up CT 1 year later: Five had increased in diameter, two had decreased, and 18 remained unchanged. All 16 thyroid masses were due to goiter; none of these were changed at follow-up CT 1 year later. CONCLUSION: Mediastinal masses found in the context of CT screening for lung cancer in asymptomatic people should be approached in a "conservative" manner; this includes thymic masses smaller than 3 cm in diameter, as most of these remain unchanged or even decrease in size.     

CAD in screening mammography

OBJECTIVE: The benefit and cost of computer-assisted detection (CAD) mammography screening remains a topic of great interest in breast imaging. Our purpose is to reflect on and interleave two articles in this issue of the AJR that highlight the difficulty in assessing the actual benefit of using CAD from either retrospective or prospective studies. CONCLUSION: This commentary describes the possible benefit and some of the issues associated with the clinical use of current CAD technology while emphasizing the expectation of and need for future improvements in CAD performance.     

The clinical importance of axillary lymphadenopathy detected on screening mammography: revisited

AIM: The aim of this study was to re-evaluate our protocol for the management of isolated axillary lymphadenopathy (ALP) on mammographic screening. METHODS: In a retrospective review of 200,716 women screened at the South West London Breast Screening Service (SWLBSS) over 7 years, 72 women with ALP with an otherwise normal mammogram were identified. Thirteen patients were not recalled, nine of who had a known underlying diagnosis and the remainder had longstanding unchanged mammograms. Fifty-nine patients were recalled for further clinical assessment and investigations, including ultrasound, further mammographic views, fine-needle aspiration cytology (FNAC), blood tests and a chest radiograph. Those with a definite diagnosis were referred for appropriate management and those with benign reactive cytology on FNAC reviewed at 6 weeks with subsequent referral for excision of persisting abnormal nodes. RESULTS: The ultimate diagnosis was benign in 45 cases: 26 benign reactive changes, 11 arthritides, five with dermatological and viral conditions and three with tuberculosis. Malignancy was diagnosed in 13 cases: four with metastatic breast carcinoma and nine with lymphoma/leukaemia. The total number of newly diagnosed malignancies was 20% of women recalled. Another 5% of patients had active tuberculosis. Of the 22 patients with benign reactive cytology, one had significant pathology on excision biopsy: tuberculosis. Over 95% of the results from excision biopsy in these patients did not alter management. CONCLUSION: In the majority of patients, the FNAC results were representative of the final excision pathology. The present study suggests that excision biopsy could be omitted for those patients whose FNAC and culture are negative.     

Medical audit of a rapid-throughput mammography screening practice: methodology and results of 27,114 examinations

Medical audit results from the entire experience of a rapid-throughput mammography screening practice are presented, comprising 27,114 examinations conducted from April 1985 to September 1989. The authors screened a self-selected physician-referred population, almost 94% of whom were asymptomatic. Estimated sensitivity of initial mammography interpretation was 93.1% with a specificity of 94.2% and a positive predictive value of 10.0%. Biopsies prompted by screening yielded a diagnosis of malignancy in 32.1% of cases; 170 breast cancers were identified, 67.1% requiring mammographic needle localization. Median cancer size was 12 mm, the rate of axillary nodal metastasis was 11.0%, and the systemic metastasis rate was 1.2%. Of the cancers found, 76.5% were stage 0 or stage 1. Conducting a medical audit is the most convincing way to demonstrate the success of a mammography screening practice, thereby providing this important information for the benefit of screenees, referring physicians, third-party payers, and the personnel who perform the screening.     

Full-field digital mammography compared to screen film mammography in the prevalent round of a population-based screening programme: the Vestfold County Study

The purpose of the study was to compare the performance of full-field digital mammography (FFDM) with soft-copy reading to screen film mammography (SFM) used during the first prevalent 2-year round of population-based screening. A total of 18,239 women aged 50–69 years were screened with FFDM as part of the Norwegian Breast Cancer Screening Programme (NBCSP). Process indicators were compared to data from 324,763 women screened with SFM using the common national database of the NBCSP. The cancer detection rates were 0.77% (140/18,239) for FFDM and 0.65% (2,105/324,763) for SFM (p = 0.058). For ductal carcinoma in situ (DCIS) alone, the results were: FFDM 0.21% (38/18,239) compared to SFM 0.11% (343/324,763) (p < 0.001). Recall rates due to positive mammography were for FFDM 4.09% (746/18,239), while for SFM 4.16% (13,520/324,764) (p = 0.645), due to technically insufficient imaging: FFDM 0.22% (40/18,239) versus SFM 0.61% (1,993/324,763) (p < 0.001). The positive predictive value (PPV) in the FFDM group was 16.6% (140/843), while 13.5% (2,105/15,537) for SFM (p = 0.014). No statistically significant differences were recorded concerning histological morphology, tumour size, or lymph node involvement. In conclusion FFDM had a significantly higher detection rate for DCIS than SFM. For invasive cancers no difference was seen. FFDM also had a significantly higher PPV and a significantly lower technical recall rate.     

The usefulness of computers in managing the operation of a mammography screening practice

A conventional desktop microcomputer can be programmed to carry out a wide variety of activities that are useful in the operation and management of a mammography screening practice. These include storage and retrieval of the records of screening examinations, direct entry of film interpretation data by the radiologist, automatic printing of examination reports, scheduling of screening appointments, tracking of follow-up procedures (including the generation of reminder letters to clients and referring physicians), and the conduct of medical audits of screening results. In general, computer-based activities can be completed more rapidly, more reliably, and at lower cost than the conventional operations they are designed to replace. All mammography screening practices can benefit from computer support.     

Clinical outcome assessment in mammography: an audit of 7,506 screening and diagnostic mammography examinations

PURPOSE: To perform an audit of our routine mammographic practice and to compare our results to performance benchmarks. MATERIALS AND METHODS: We analyzed the outcomes of 7,506 consecutive examinations performed in 1 year. Screening and diagnostic cases were evaluated separately and mammographic assessments were based on the Breast Imaging Reporting and Data System (BI-RADS) classification. RESULTS: In 6,858 (91%) screening and 648 (9%) diagnostic cases, outcomes varied substantially. The recall rate was 10.9%. Estimated sensitivity and specificity were similar (100% vs. 98% and 88% vs. 94%) in the screening and diagnostic groups. Positive predictive values (PPV1, PPV2, and PPV3) were higher in the diagnostic group compared to the screening group (64%, 65%, and 68% vs. 4.9%, 33%, and 39%, respectively). Cancer outcomes in the screening and diagnostic groups were, respectively, as follows: cancer detection rate, 6.1 per thousand vs. 86.4 per thousand; mean invasive cancer size, 15.7 mm vs. 24.5 mm; minimal cancers, 38% vs. 19%; stage 0-1 cancers, 50% vs. 21%; and lymph node negativity, 76% vs. 29%. CONCLUSION: The measures of our screening outcomes were concordant with the literature and the performance benchmarks for screening mammography; however, in our diagnostic group, the reasons for the higher PPV, higher cancer detection rate, and the diagnosis of cancer in a more advanced stage compared to the performance benchmarks should be investigated with more detailed periodic audits.     

Computer-aided detection in screening mammography: variability in cues

PURPOSE: To evaluate the variability of true-positive and false-positive cues by using a commercially available computer-aided detection (CAD) system for analysis of 50 malignancies in a screening population. MATERIALS AND METHODS: Fifty breast cancers detected at screening were analyzed by using a commercially available CAD system. Mean patient age was 62.2 years. Each set of mammograms (craniocaudal and mediolateral oblique views) was digitized and analyzed by the CAD system 10 times. One radiologist compared CAD output with the location of the malignancy at mammography and determined whether each lesion was marked accurately in one mammographic view, both views, or neither. Sensitivity and reproducibility of the CAD system were determined for both case- and image-based analysis. RESULTS: Overall sensitivity of the CAD system when at least one of the two mammographic views was marked correctly (case-base sensitivity) was 82.4%. Sensitivity when each mammographic view was considered separately (image-based sensitivity) was 61.1%. For case-based analysis, variability in true-positive CAD cues was demonstrated for 14 of 50 (28%) cases. For image-based analysis, inconsistency in CAD output was observed in 33 of 100 (33%) mammographic views that contained malignancies detected at screening. However, the CAD system consistently detected 40-43 of the 50 breast cancers in each of the 10 CAD runs. Variability for false-positive marks was significantly greater than that for true-positive marks. CONCLUSION: Inconsistency was demonstrated for CAD analysis of breast cancers detected at screening. However, the CAD system was reasonably consistent in the overall number of cancers identified from run to run. Greater variability of the CAD system was also demonstrated for false-positive marks, as compared with true-positive marks.     

Economic issues in screening mammography.

The issues surrounding screening mammography present apparent conflicts: conflicting guidelines for screening; an oversupply of facilities, yet inadequate access to mammography for some groups of women; increased medicolegal vulnerability as participation in screening is promoted; disparate results from studies of cost-effectiveness; wide variations in delivery modes and practice patterns of facilities, yet an evolution toward a single set price for mammography by payers for screening. This review does not claim to offer solutions to these conflicts, rather it attempts to carry forward a discussion of the issues. With these conflicts, screening mammography may be only a microcosm of similar economic issues in general health care delivery. Our health care system has room for variety, if access and quality are improved at an affordable cost. Screening for breast cancer with mammography will not reach its full potential to reduce mortality until many of these issues can be resolved.     

Auditing and benchmarks in screening and diagnostic mammography

Radiologists can use outcome data such as cancer size and stage to determine how well their own practice provides benefit to their patients and can use measures such as screening recall rates and positive predictive values to assess how well adverse consequences are being contained. New data on national benchmarks for screening and diagnostic mammography in the United States allow radiologists to evaluate their own performance with respect to their peers. This article discusses recommended outcome values in the United States and Europe, current Mammography Quality Standards Act audit requirements, and Institute of Medicine proposals for future requirements.     

Real-time reading in mammography breast screening

PURPOSE: This study was undertaken to assess the role of real-time reading in the mammography screening programme carried out at the Hospital of Marzana, Verona, Italy. MATERIALS AND METHODS: During the 5-year period 1999-2004, 54,472 women attended the screening programme (32,291 first calls: unadjusted uptake 41.4%, adjusted uptake 50.3%; 21,551 2- year routine recalls: unadjusted uptake 86.4%, adjusted uptake 89.9%). Further diagnostic investigations [(FDI), imaging and cytohistological] were performed immediately after real-time reading of the screening mammograms (FDI rate among first calls 10.9%; FDI rate among 2-year recalls 5.4%). Overall, cytohistological FDI were requested in 27% of imaging FDI, with a clear prevalence of cytological [fine-needle aspiration cytology (FNAC) 87%] over histological procedures [core needle biopsy (CNB) 11%; vacuum aspiration biopsy (VAB) 2%]. RESULTS: Imaging FDI proved to be conclusive in 73%. Cytohistological FDI led to the use of surgical biopsy (SB) in 39.5% (ratio between benign and malignant SB: 0.19/first calls, 0.14/2-year recalls). There were a total of 427 screen-detected breast cancers (BC), with a very good breast cancer detection rate (BCDR/first calls 9.7 per thousand; BCDR/2-year recalls 5.1 per thousand). In the 427 screen-detected BC, the incidence of pTis, pT1a,b cancers was 59.6% (diagnostic anticipation); the incidence of pN0 cancers was 61.2%; the incidence of conservative surgical procedures was 78.6%. In interval cancers, the false negative rate was 8.3% only, whereas the proportional incidence was very low indeed (14% first year; 38% second year). CONCLUSIONS: The high sensitivity exhibited by the Marzana mammography screening programme suggests that the value of real-time reading should be validated by other programmes adopting a similar approach.