A randomised trial of screening with digital breast tomosynthesis plus conventional digital 2D mammography versus 2D mammography alone in younger higher risk women

IntroductionDigital breast tomosynthesis (DBT) has been shown to increase invasive cancer detection rates at screening compared to full field digital (2D) mammography alone, and some studies have reported a reduction in the screening recall rate. No prospective randomised studies of DBT have previously been published. This study compares recall rates with 2D mammography with and without concurrent DBT in women in their forties with a family history of breast cancer undergoing incident screening.Materials and methodsAsymptomatic women aged 40–49 who had previously undergone mammography for an increased risk of breast cancer were recruited in two screening centres. Participants were randomised to screening with 2D mammography only at the first study screen followed a year later by screening with 2D plus DBT, or vice versa. Recall rates were compared using an intention to treat analysis. Reading performance was analysed for the larger centre.Results1227 women were recruited. 1221 first screens (604 2D, 617 2D + DBT) and 1124 second screens (558 2D + DBT, 566 2D) were analysed. Eleven women had screen-detected cancers: 5 after 2D, 6 after 2D + DBT. The false positive recall rates were 2.4% for 2D and 2.2% for 2D + DBT (p = 0.89). There was a significantly greater reduction between rounds in the number of women with abnormal reads who were not recalled after consensus/arbitration with 2D + DBT than 2D (p = 0.023).ConclusionThe addition of DBT to 2D mammography in incident screening did not lead to a significant reduction in recall rate. DBT may increase reader uncertainty until DBT screening experience is acquired.     

Detection of Contralateral Breast Cancer Using Diffusion-Weighted Magnetic Resonance Imaging in Women with Newly Diagnosed Breast Cancer: Comparison with Combined Mammography and Whole-Breast Ultrasound

ObjectiveTo compare the screening performance of diffusion-weighted (DW) MRI and combined mammography and ultrasound (US) in detecting clinically occult contralateral breast cancer in women with newly diagnosed breast cancer.Materials and MethodsBetween January 2017 and July 2018, 1148 women (mean age ± standard deviation, 53.2 ± 10.8 years) with unilateral breast cancer and no clinical abnormalities in the contralateral breast underwent 3T MRI, digital mammography, and radiologist-performed whole-breast US. In this retrospective study, three radiologists independently and blindly reviewed all DW MR images (b = 1000 s/mm² and apparent diffusion coefficient map) of the contralateral breast and assigned a Breast Imaging Reporting and Data System category. For combined mammography and US evaluation, prospectively assessed results were used. Using histopathology or 1-year follow-up as the reference standard, cancer detection rate and the patient percentage with cancers detected among all women recommended for tissue diagnosis (positive predictive value; PPV₂) were compared.ResultsOf the 30 cases of clinically occult contralateral cancers (13 invasive and 17 ductal carcinoma in situ [DCIS]), DW MRI detected 23 (76.7%) cases (11 invasive and 12 DCIS), whereas combined mammography and US detected 12 (40.0%, five invasive and seven DCIS) cases. All cancers detected by combined mammography and US, except two DCIS cases, were detected by DW MRI. The cancer detection rate of DW MRI (2.0%; 95% confidence interval [CI]: 1.3%, 3.0%) was higher than that of combined mammography and US (1.0%; 95% CI: 0.5%, 1.8%; p = 0.009). DW MRI showed higher PPV₂ (42.1%; 95% CI: 26.3%, 59.2%) than combined mammography and US (18.5%; 95% CI: 9.9%, 30.0%; p = 0.001).ConclusionIn women with newly diagnosed breast cancer, DW MRI detected significantly more contralateral breast cancers with fewer biopsy recommendations than combined mammography and US.     

Contrast-enhanced spectral mammography as work-up tool in patients recalled from breast cancer screening has low risks and might hold clinical benefits

ObjectiveContrast-enhanced spectral mammography (CESM) is a reliable problem solving tool in the work-up of women recalled from breast cancer screening. We evaluated additional findings caused by CESM alone and outweighed them against the disadvantages of this technique.MethodsFrom December 2012 to December 2015, all women recalled from screening who underwent CESM were considered for this study. Radiation exposure and number of adverse contrast reactions were analysed. An experienced breast radiologist reviewed all exams and identified cases with lesions detected by CESM alone and scored their conspicuity. From these cases, data on breast density and final diagnosis were collected. For malignant cases, tumour grade and receptor characteristics were also collected.ResultsDuring this study, 839 women underwent CESM after a screening recall, in which five minor adverse contrast reactions were observed. Median radiation dose per exam was 6.0 mGy (0.9–23.4 mGy). Seventy CESM-only lesions were detected in 65 patients. Of these 70 lesions, 54.3% proved to be malignant, most commonly invasive ductal carcinomas. The remaining CESM-only lesions were benign, predominantly fibroadenomas. No complications were observed during biopsy of these lesions. Retrospectively, the majority of the lesions were either occult or a ‘minimal sign’ on low-energy CESM images or the screening mammogram.ConclusionUsing CESM as a work-up tool for women recalled from screening carries low risk for the patient, while additionally detected tumour foci might hold important clinical implications which need to be further studied in large, randomized controlled trials.     

Impact of the New Jersey Breast Density Law on Imaging and Intervention Volumes and Breast Cancer Diagnosis

PurposeIncreased breast density is acknowledged as an independent risk factor for breast cancer and may obscure malignancy on mammography. Approximately half of all mammograms depict dense breasts. Legislation related to mandatory breast density notification was first enacted in Connecticut in 2009. On May 1, 2014, New Jersey joined other states with similar legislation. The New Jersey breast density law (NJBDL) mandates that mammography reports acknowledge the relevance and masking effect of mammographic breast density. The aim of this study was to assess the impact of the NJBDL at one of the state’s largest ACR-accredited breast centers.MethodsA retrospective chart review was performed to determine changes in imaging and intervention utilization and modality of cancer diagnosis after enactment of the legislation. Data for the present study were extracted from a review of all patients with core biopsy–proven malignancy at a large outpatient breast center between November 1, 2012, and October 31, 2015. Data were divided into the 18-month period before the implementation of the NJBDL (November 1, 2012 to April 30, 2014) and the 18-month period after passage of the law (May 1, 2014 to October 31, 2015).ResultsScreening ultrasound increased significantly after the implementation of the NJBDL, by 651% (1,530 vs 11,486). MRI utilization increased by 59.3% (2,595 vs 4,134). A total of 1,213 cancers were included in the final analysis, 592 in the first time period and 621 after law implementation. Breast cancer was most commonly detected on screening mammography, followed by diagnostic mammography with ultrasound for palpable concern, in both time periods. Of the 621 cancers analyzed, 26.1% (n = 162) were found in patients 50 years of age or younger. Results demonstrated that with respect to how malignancies were detected, age and average mammographic density were both statistically significant (P = .002).ConclusionsThe NJBDL succeeded in publicizing the masking effect of dense breasts. The number of supplemental screening ultrasound and MRI examinations increased after the implementation of this legislation. An efficacy analysis affirmed the high sensitivity of screening MRI compared with other modalities. The use of MRI increased core biopsy efficiency and reduced the number of biopsies needed per cancer diagnosed.     

Visibility of mammographically occult breast cancer on diffusion-weighted MRI versus ultrasound

PurposeTo investigate the visibility of mammographically occult breast cancers on diffusion-weighted MRI (DWI) versus ultrasound.Materials and methodsMammographically occult breast cancers (n = 60) initially detected on contrast-enhanced MRI that underwent pre-biopsy targeted ultrasound were retrospectively evaluated for visibility on DWI and ultrasound.ResultsMore cancers were visible on DWI than ultrasound (78% vs. 63%; p = 0.049), with 32 (53%) visible on both and 7 (12%) not visible on either. Visibility differences were more significant in larger lesions (92% vs. 68%, p = 0.006).ConclusionDWI may detect more mammographically occult cancers than ultrasound, warranting further investigation as an alternative supplemental screening technique.     

Simultaneous whole-body 18F-FDG PET-MRI in primary staging of breast cancer: A pilot study

PurposeAccurate initial staging in breast carcinoma is important for treatment planning and for establishing the likely prognosis. The purpose of this study was to assess the utility of whole body simultaneous ¹⁸F-FDG PET-MRI in initial staging of breast carcinoma.Methods36 patients with histologically confirmed invasive ductal carcinoma underwent simultaneous whole body ¹⁸F-FDG PET-MRI on integrated 3 T PET-MR scanner (Siemens Biograph mMR) for primary staging. Primary lesion, nodes and metastases were evaluated on PET, MRI and PET-MRI for lesion count and diagnostic confidence (DC). Kappa co relation analysis was done to assess agreement between the satellite, nodal and metastatic lesions detected by PET and MRI. Histopathology, clinical/imaging follow-up served as the reference standard.Results36 patients with 37 histopathologically proven index breast cancer were retrospectively studied. Of 36 patients, 25 patients underwent surgery and 11 patients received systemic therapy. All index cancers were seen on PET and MR. Fused PET-MRI showed highest diagnostic confidence score of 5 as compared to PET (median 4; range 3–5) and MRI (median 4; range 4–5) alone. 2/36 (5.5%) patients were detected to have unsuspected contralateral synchronous cancer. 47 satellite lesions were detected on DCE MRI of which 23 were FDG avid with multifocality and multicentricity in 21 (58%) patients. Kappa co relation analysis revealed fair agreement for satellite lesion detection by the two modalities (κ = 0.303; P = 0.003).The study showed a sensitivity of 60% and 93.3% on PET and MRI respectively for detection of axillary lymph nodes with a specificity of 91% for both and a false negative rate of 6.7% on MRI and 40% on PET. Kappa co relation analysis between PET and MRI for all the lymph nodes detected revealed fair agreement by the two modalities (κ = 0.337; P = 0.000). Combined PET-MRI increased diagnostic confidence for nodal involvement (median DC 5, range 4–5; P < 0.05).Distant metastases were found in 8/36 (22%) patients at the time of diagnosis with a total of 91 metastatic lesions on PET (DC ≥ 4) and 105 on MRI (DC ≥ 4), the difference being statistically significant (P = 0.001) while Kappa co relation analysis showed significant agreement between the two modalities (κ = 0.667; P = 0.000). Overall PET-MRI led to a change in management in 12 (33.3%) patients.ConclusionIn this pilot study, simultaneous ¹⁸F-FDG PET-MR, has been found to be useful in whole-body initial staging of breast cancer patients.     

Accuracy of contrast-enhanced spectral mammography compared with MRI for invasive breast cancers: Prospective study in population of predominantly underrepresented minorities

ObjectivesThis prospective study compares contrast-enhanced spectral mammography (CESM) with contrast-enhanced breast MRI in assessing the extent of newly diagnosed breast cancer in a multiethnic cohort.MethodsThis study includes 41 patients with invasive breast cancer detected by mammography or conventional ultrasound imaging from May 2017 to March 2020. CESM and MRI scans were performed prior to any treatment. Results are compared with each other and to histopathology. Detection of the malignant lesion was assessed by sensitivity, specificity, PPV, NPV. Consistency of malignant tumor size measurement was compared between modalities using Intraclass Correlation Coefficient (ICC).ResultsIn a multiethnic cohort with over 65% Hispanic and African-American women, the sensitivity of detecting malignant lesions for CESM is 93.1% (77.23%, 99.15%) and MRI is 96.55% (82.24%, 99.91%). The PPV for CESM 96.43% (81.65%, 99.91%) is better compared to MRI 82.35% (65.47%, 93.24%). CESM is as effective as MRI in evaluating index cancers and multifocal/multicentric/contralateral disease. CESM has greater specificity and PPV since MRI tends to overcall benign lesions. There is a good agreement of tumor size between CESM to surgery and MRI to surgery with ICC of 0.85 (95% CI 0.69, 0.93) and 0.87 (95% CI 0.74, 0.94), respectively. There is good agreement of malignancy detection between CESM and MRI with Kappa of 0.74 (95% CI 0.52, 0.95).ConclusionsCESM is an effective imaging modality for evaluating the extent of disease in newly diagnosed invasive breast cancers and a good alternative to MRI in a multiethnic population.     

Travel Burden to Breast MRI and Utilization: Are Risk and Sociodemographics Related?

PurposeMammography, unlike MRI, is relatively geographically accessible. Additional travel time is often required to access breast MRI. However, the amount of additional travel time and whether it varies on the basis of sociodemographic or breast cancer risk factors is unknown.MethodsThe investigators examined screening mammography and MRI between 2005 and 2012 in the Breast Cancer Surveillance Consortium by (1) travel time to the closest and actual mammography facility used and the difference between the two, (2) women’s breast cancer risk factors, and (3) sociodemographic characteristics. Logistic regression was used to examine the odds of traveling farther than the closest facility in relation to women’s characteristics.ResultsAmong 821,683 screening mammographic examinations, 76.6% occurred at the closest facility, compared with 51.9% of screening MRI studies (n = 3,687). The median differential travel time among women not using the closest facility for mammography was 14 min (interquartile range, 8-25 min) versus 20 min (interquartile range, 11-40 min) for breast MRI. Differential travel time for both imaging modalities did not vary notably by breast cancer risk factors but was significantly longer for nonurban residents. For non-Hispanic black compared with non-Hispanic white women, the adjusted odds of traveling farther than the closest facility were 9% lower for mammography (odds ratio, 0.91; 95% confidence interval, 0.87-0.95) but more than two times higher for MRI (odds ratio, 2.64; 95% confidence interval, 1.36-5.13).ConclusionsBreast cancer risk factors were not related to excess travel time for screening MRI, but sociodemographic factors were, suggesting the possibility that geographic distribution of advanced imaging may exacerbated disparities for some vulnerable populations.     

Prediction of near-term risk of developing breast cancer using computerized features from bilateral mammograms

Asymmetry of bilateral mammographic tissue density and patterns is a potentially strong indicator of having or developing breast abnormalities or early cancers. The purpose of this study is to design and test the global asymmetry features from bilateral mammograms to predict the near-term risk of women developing detectable high risk breast lesions or cancer in the next sequential screening mammography examination. The image dataset includes mammograms acquired from 90 women who underwent routine screening examinations, all interpreted as negative and not recalled by the radiologists during the original screening procedures. A computerized breast cancer risk analysis scheme using four image processing modules, including image preprocessing, suspicious region segmentation, image feature extraction, and classification was designed to detect and compute image feature asymmetry between the left and right breasts imaged on the mammograms. The highest computed area under curve (AUC) is 0.754 ± 0.024 when applying the new computerized aided diagnosis (CAD) scheme to our testing dataset. The positive predictive value and the negative predictive value were 0.58 and 0.80, respectively.     

Role of MRI in screening women at high risk for breast cancer

Breast cancer is diagnosed in over one million women worldwide every year. Until breast cancer can be prevented, early detection offers the best chance for cure. Mammographic screening is an effective method for early detection in average-risk women. However, the sensitivity of mammography is decreased in women at high risk for breast cancer. Because of its high sensitivity, multiple investigators have studied the potential role of MRI in screening women at high risk. In the past few years, results from eight major clinical trials exploring breast MRI as a screening tool have been published. Combined, the studies included 4271 patients and found 144 breast cancers detected by MRI, for an overall cancer yield of 3%. The sensitivity of MRI ranged from 71% to 100% across the studies. Although its reported specificity was variable, the call-back rates and risk of benign biopsies were within acceptable limits. In general, patients who underwent breast MRI screening had a 10% risk of being called back, and a 5% risk of having a benign biopsy. This work reviews the literature and current practices and recommendations for MRI as a screening tool for high-risk women.     

Compression force and radiation dose in the Norwegian Breast Cancer Screening Program

PurposeCompression force is used in mammography to reduce breast thickness and by that decrease radiation dose and improve image quality. There are no evidence-based recommendations regarding the optimal compression force. We analyzed compression force and radiation dose between screening centers in the Norwegian Breast Cancer Screening Program (NBCSP), as a first step towards establishing evidence-based recommendations for compression force.Materials and methodsThe study included information from 17 951 randomly selected screening examinations among women screened with equipment from four different venors at fourteen breast centers in the NBCSP, January-March 2014. We analyzed the applied compression force and radiation dose used on craniocaudal (CC) and mediolateral-oblique (MLO) view on left breast, by breast centers and vendors.ResultsMean compression force used in the screening program was 116N (CC: 108N, MLO: 125N). The maximum difference in mean compression force between the centers was 63N for CC and 57N for MLO. Mean radiation dose for each image was 1.09 mGy (CC: 1.04mGy, MLO: 1.14mGy), varying from 0.55 mGy to 1.31 mGy between the centers. Compression force alone had a negligible impact on radiation dose (r² = 0.8%, p = < 0.001).ConclusionWe observed substantial variations in mean compression forces between the breast centers. Breast characteristics and differences in automated exposure control between vendors might explain the low association between compression force and radiation dose. Further knowledge about different automated exposure controls and the impact of compression force on dose and image quality is needed to establish individualised and evidence-based recommendations for compression force.     

Breast Arterial Calcification on screening mammography can predict significant Coronary Artery Disease in women

IntroductionBreast Arterial Calcification (BAC) on digital mammography has been associated with an increased risk of Coronary Artery Disease (CAD). We aimed to investigate the association of BAC with findings on Coronary Computed Tomography Angiography (CCTA) within a cohort of women from the national breast screening program.MethodsSymptomatic women (chest pain) aged between 50 and 65 who underwent a CCTA and who also had a screening mammography between 2014 and 2015 were recorded. BAC and CAD-RADS™: Coronary Artery Disease–Reporting and Data System were scored by separate blinded specialist radiologists. Cardiac risk factors were recorded. Patients' cardiac follow up (with Exercise Stress Test, Percutaneous Coronary Intervention or echocardiography) and cardio-protective medications were also documented.Results219 eligible women underwent a CCTA. Of these, 104 patients also underwent digital mammography. Using standard linear regression BAC was identified as a significant predictor of CAD-RADs ≥ 3 disease. Using binomial logistic regression, BAC remained associated with CAD-RADs ≥ 3 (p = 0.023). A significantly higher proportion of patients with BAC > 1 were on cardio-protective medications (p = 0.041) and had medications initiated or changed, or had further cardiac investigation (p = 0.037 and p = 0.019, respectively) than those with no BAC, after a mean follow-up of 20.6 (range 15–27) months.ConclusionBAC diagnosed on 2 yearly screening mammography predicts CAD-RADs ≥ 3 disease in symptomatic patients.     

Using sonography to screen women with mammographically dense breasts

OBJECTIVE: Mammographically dense breast tissue has been reported both as a cause of false-negative findings on mammography and as an indicator of increased breast cancer risk. We conducted this study to evaluate the role of breast sonography as a second-line screening test in women with mammographically dense breast tissue. MATERIALS AND METHODS: Between January 2000 and January 2002, 1517 asymptomatic women with dense breasts and normal mammography and physical examination findings underwent physician-performed breast sonography as an adjunct screening test. Within the study group, 318 women had a first-degree family history or personal history of breast cancer. The high-risk subgroup comprised these women. The detection rate of breast cancer in this subgroup was compared with the detection rate in the remaining study population with baseline risk. RESULTS: Of 1517 women examined, seven breast cancers were diagnosed (cancer-detection rate, 0.46%). Four carcinomas were detected in high-risk women and three in women with baseline risk. The cancer-detection rate in the subgroup of high-risk women was 1.3%, significantly higher (p < 0.04) than the cancer-detection rate of 0.25% in the baseline risk subgroup. All cancers were T1 (range, 4-12 mm; mean, 9.6 mm). Sentinel lymph nodes were negative for cancer in six of seven carcinomas. CONCLUSION: Screening breast sonography in the population of women with dense breast tissue is useful in detecting small breast cancers that are not detected on mammography or clinical breast examination. The use of sonography as an adjunct to screening mammography in women with increased risk of breast cancer and dense breasts may be especially beneficial.     

Preoperative breast MR Imaging in patients with primary breast cancer has the potential to decrease the rate of repeated surgeries

PurposeThe impact of preoperative MRI on re-excisions and mastectomy rate is discussed controversially in the literature. Aim of this study was to evaluate the effect of preoperative breast MRI on the surgical procedure and rate of repeated surgeries.Material and methodsA total of 991 consecutive patients in the years 2009 and 2010 with 1036 primary breast cancers were retrospectively analyzed. Sixty percent (599 patients with 626 cancers) received preoperative breast MRI. Planned surgical procedures before and after MRI and numbers of repeated surgeries in patients with (MR+ ) and without preoperative MRI (MR−) were compared.ResultsThe result of preoperative MRI changed the surgical procedure in 25% (157/626) of the cases. In 81% (127/157), MRI was beneficial for the patients, as otherwise occult carcinomas were removed (n = 122) or further biopsy could be prevented (n = 5). Mastectomy rates did not differ between MR+ and MR- group (39% vs. 39%). On multiple regression analysis, the MR+ group had a lower chance for repeated surgery (p < 0.05).ConclusionPreoperative MRI could lower the chance for repeated surgery in patients with primary breast cancer. The rate of mastectomy did not differ between patients undergoing preoperative MRI and those who did not.     

Background uptake of breast-specific gamma imaging: correlation with mammographic breast density and background enhancement of breast MRI

PurposeTo investigate the relationship between background uptake of breast-specific gamma imaging (BSGI) mammographic breast density and background enhancement of breast magnetic resonance imaging (MRI).Materials and methodsThe level and texture of background uptake of BSGI, mammographic breast density, and background enhancement of breast MRI are retrospectively reviewed in 104 patients.ResultsHeterogeneous and increased background uptake of BSGI was significantly correlated with high mammographic breast density (P= .016, P= .001) and increased background enhancement of breast MRI (P= .015, P= .017).ConclusionInterpreting BSGI of women showing high mammographic breast density or background enhancement of breast MRI needs to be carried out with caution.     

The use of magnetic resonance imaging in breast cancer screening

Screening mammography is a powerful tool for reducing breast cancer mortality. Mammography can often detect clinically occult, early-stage breast cancer that is amenable to successful treatment. However, mammography is not a perfect test and has lower sensitivity in young women and in those with dense breasts. Magnetic resonance imaging (MRI) has been shown to depict breast cancers that are occult to other forms of detection, including mammography. This has generated interest in the use of MRI for breast cancer screening. Although preliminary studies in highly selected populations show promise for the potential efficacy of breast cancer screening with MRI, there are many questions that should be addressed before this technique is offered to the general population.     

Valoración de los factores pronósticos radiopatológicos del cáncer de mama triple negativo y análisis del carcinoma in situ como factor pronóstico

ObjectivesTo analyze what factors in magnetic resonance imaging (MRI) and histological study of triple-negative breast cancers are related to tumor recurrence and to shorter disease-free survival. To analyze survival and recurrence in function of the presence of an in situ component.Material and methodsThis was a retrospective study of MRI staging examinations in 122 women with triple-negative breast cancer done from 2007 through 2014. In the MRI, we evaluated morphological variables (size, margins, morphology, internal signal in T2-weighted sequences) and dynamic variables (perfusion and diffusion). In the histological study, we evaluated Ki67, p53, CK5/6, nuclear grade, and Scarff-Bloom grade, as well as the presence of an in situ component and tumor grade (high grade or not high grade). We compared the variables between patients with tumor recurrence and those without, and we conducted a survival analysis.ResultsNon-nodular enhancement was more common in patients with tumor recurrence (p  = 0.038) and was associated with shorter disease-free survival (p = 0.023). Neither diffusion restriction (p = 0.079) nor ki67 (p = 0.052) was associated with a worse prognosis. An in situ component was detected in 44% of triple-negative tumors, and a greater proportion of patients in the group with tumor recurrence had an in situ component; however, the presence of an in situ component was not associated with shorter survival (p = 0.185).ConclusionNon-nodular enhancement was associated with a worse prognosis. Diffusion restriction, ki67, and the presence of an in situ component were not associated with shorter disease-free survival.     

Effective lifetime radiation risk for a number of national mammography screening programmes

Background and purposeThe performance of mammography screening programmes is focussed mainly on breast cancer detection rates. However, when the benefits and risks of mammography are considered, the risk of radiation-induced cancer is calculated for only the examined breast using Mean Glandular Dose (MGD). The risk from radiation during mammography is often described as low or minimal. This study aims to evaluate the effective lifetime risk from full field digital mammography (FFDM) for a number of national screening programmes.Material and MethodsUsing an ATOM phantom, radiation doses to multiple organs were measured during standard screening mammography. Sixteen FFDM machines were used and the effective lifetime risk was calculated across the female lifespan for each machine. Once the risks were calculated using the phantom, the total effective lifetime risk across 48 national screening programmes was then calculated; this assumed that all these programmes use FFDM for screening.ResultsLarge differences exist in effective lifetime risk, varying from 42.21 [39.12–45.30] cases/10⁶ (mean [95% CI]) in the Maltese screening programme to 1099.67 [1019.25–1180.09] cases/10⁶ for high breast cancer risk women in the United States of America. These differences are mainly attributed to the commencement age of screening mammography and the time interval between successive screens.ConclusionsEffective risk should be considered as an additional parameter for the assessment of screening mammography programme performance, especially for those programmes which recommend an early onset and more frequent screening mammography.