Long-term quality of life among breast cancer survivors eligible for screening at diagnosis: a systematic review and meta-analysis.

OBJECTIVES: This study aimed to explore the long-term quality of life (QoL) among breast cancer survivors eligible for mammographic screening at diagnosis and compare that to QoL among women with no history of breast cancer. STUDY DESIGN: Systematic review and meta-analysis. METHODS: A systematic review of randomised controlled trials and observational studies published between January 2000 and July 2019 was performed. Eight studies were included in the review. Six studies with QoL measurement scales (0-100) were included in the meta-analysis. We used fixed and random effects models to obtain Cohen's d with 95% confidence interval (CI). Heterogeneity among studies was evaluated by the I2 statistics. RESULTS: Information about 6145 breast cancer survivors diagnosed between 1995 and 2012 and followed for >1-10 years was analysed. Four studies used SF-36/RAND-36, three studies used EORTC QLQ-C30, one study used FACT-G and one study used FACT-B. The mean score of QoL for breast cancer survivors varied from 63.0 (RAND SF-36, 0-100) to 110.5 (FACT-B, 0-123). Two studies showed better, three studies showed similar and two studies showed poorer mean scores for breast cancer survivors compared with women with no history of breast cancer. The meta-analysis showed no significant differences in QoL for breast cancer survivors compared with women with no history of breast cancer (Cohen's d = -0.07, 95% confidence interval [CI] -0.14 to 0.00 and I2 = 83.7% for the fixed effect model; Cohen's d = -0.00, 95% CI -0.18 to 0.17 and I2 = 82.4% for the random effects model). CONCLUSION: QoL did not differ between breast cancer survivors eligible for mammographic screening at diagnosis and followed for >1-10 years and women with no history of breast cancer.

Temporal trends in age at menarche and age at menopause: a population study of 312 656 women in Norway.

STUDY QUESTION: Have mean age at menarche or mean age at natural menopause changed from the 1939 birth cohort to the 1964 birth cohort? SUMMARY ANSWER: We estimated a minor decrease in mean age at menarche and an increase by nearly 3 years in mean age at natural menopause. WHAT IS KNOWN ALREADY: In the Western world, age at menarche decreased across birth cohorts from the early 1800s until the 1950s. Whether mean age at menarche has continued to decrease in birth cohorts after the 1950s remains uncertain. It is also uncertain whether mean age at natural menopause has changed across birth cohorts. STUDY DESIGN, SIZE, DURATION: We performed a retrospective population study of 312 656 women who were born in Norway during the years 1936-1964. PARTICIPANTS/MATERIALS, SETTING, METHODS: The data were obtained by two self-administered questionnaires from women who participated in the Norwegian breast cancer screening program (BreastScreen Norway) during the years 2006-2014. We used flexible parametric survival models with restricted cubic splines to estimate mean age at menarche, mean age at menopause and mean number of years between menarche and menopause according to the women's year of birth. The women who were still having menstrual periods contributed with follow-up time until the time of data collection, and the women who had reported surgical removal of the uterus and/or both ovaries prior to natural menopause contributed with follow-up time until the time of surgery. MAIN RESULTS AND THE ROLE OF CHANCE: The mean age at menarche was 13.42 years (95% CI: 13.40-13.44 years) among women born during 1936-1939, and it was 13.24 years (95% CI: 13.22-13.25 years) among women born during 1960-1964. The mean age at natural menopause increased from 50.31 years (95% CI: 50.25-50.37 years) among women born during 1936-1939 to 52.73 years (95% CI: 52.64-52.82 years) among women born during 1960-1964. The mean number of years between menarche and menopause increased from 36.83 years (95% CI: 36.77-36.89 years) to 40.22 years (95% CI: 40.11-40.34 years). LIMITATIONS, REASONS FOR CAUTION: Information about age at menarche and age at menopause was based on self-reports. WIDER IMPLICATIONS OF THE FINDINGS: Late menopause is associated with increased risk of breast cancer but also with increased life expectancy. Thus, higher mean age at menopause may partly explain the increase in breast cancer incidence after menopause and the increase in life expectancy in recent time. Also, a longer interval between menarche and menopause could suggest that the number of years of female fecundity has increased. STUDY FUNDING/COMPETING INTEREST(S): This work was funded by the South-Eastern Norway Regional Health Authority [grant number 2016112 to M.S.G.] and by the Norwegian Cancer Society [grant number 6863294-2015 to E.K.B.]. The authors declare no conflicts of interest.

The relation of age at menarche with age at natural menopause: a population study of 336 788 women in Norway.

STUDY QUESTION: Is age at menarche associated with age at menopause or with duration of the reproductive period (interval between menarche and menopause)? SUMMARY ANSWER: The association of age at menarche with age at menopause was weak and non-linear, and the duration of the reproductive period decreased by increasing age at menarche. WHAT IS KNOWN ALREADY: It remains uncertain whether age at menarche is associated with age at menopause. Some studies report that women with early menarche also have early menopause. Other studies report that women with early menarche have late menopause, or they report no association. The duration of the reproductive period may be an indicator of the cumulative endogenous exposure to estrogens and progestogens during life course and is associated with risk of breast cancer and endometrial cancer. STUDY DESIGN, SIZE, DURATION: A retrospective cohort study of 336 788 women, aged 48-71 years, in the BreastScreen Norway during the years 2006-2014 was performed. PARTICIPANTS/MATERIALS, SETTING, METHODS: Information about age at menarche and menopausal status was obtained by self-administered questionnaires. We used time to event approaches to estimate the associations. MAIN RESULTS AND THE ROLE OF CHANCE: Median age at menopause was 51 years in most menarche groups. Women with menarche at age 16 years or age ≥ 17 years had menopause 1 year later [median: 52 years, interquartile range (IQR): 49-54 years] than women with menarche at age 13 years (median: 51 years, IQR: 49-54 years, reference) (crude hazard ratio (HR) = 0.95; 95% CI: 0.93-0.97 and 0.95; 95% CI: 0.92-0.99, Pnon-linearity < 0.001). The reproductive period decreased with increasing age at menarche (Pnon-linearity < 0.001), and women with menarche at age ≤ 9 years had 9 years longer median reproductive period than women with menarche at age ≥ 17 years (median: 43 versus 34 years). Adjustment for year of birth did not change the HR estimates notably. LARGE SCALE DATA: Not applicable. LIMITATIONS, REASONS FOR CAUTION: Information about age at menarche and age at menopause was based on self-reports. Particularly for age at menarche, the long time interval between the event and data collection may have caused imprecise reporting. WIDER IMPLICATIONS OF THE FINDINGS: Our study suggests that age at menarche is a strong indicator for the duration of women's reproductive period. Our findings should encourage studies of the independent role of duration of the reproductive period on the risk of breast cancer and endometrial cancer, since these cancers have been associated with exposure to estrogens and progestogens. STUDY FUNDING/COMPETING INTEREST(S): The present study was funded by the Norwegian Cancer Society [Grant number 6863294-2015]. The authors declare no conflicts of interest.

The impact of mammography screening programmes on incidence of advanced breast cancer in Europe: a literature review.

BACKGROUND: Observational studies have reported conflicting results on the impact of mammography service screening programmes on the advanced breast cancer rate (ABCR), a correlation that was firmly established in randomized controlled trials. We reviewed and summarized studies of the effect of service screening programmes in the European Union on ABCR and discussed their limitations. METHODS: The PubMed database was searched for English language studies published between 01-01-2000 and 01-06-2018. After inspection of titles and abstracts, 220 of the 8644 potentially eligible papers were considered relevant. Their abstracts were reviewed by groups of two authors using predefined criteria. Fifty studies were selected for full paper review, and 22 of these were eligible. A theoretical framework for their review was developed. Review was performed using a ten-point checklist of the methodological caveats in the analysis of studies of ABCR and a standardised assessment form designed to extract quantitative and qualitative information. RESULTS: Most of the evaluable studies support a reduction in ABCR following the introduction of screening. However, all studies were challenged by issues of design and analysis which could at least potentially cause bias, and showed considerable variation in the estimated effect. Problems were observed in duration of follow-up time, availability of reliable reference ABCR, definition of advanced stage, temporal variation in the proportion of unknown-stage cancers, and statistical approach. CONCLUSIONS: We conclude that much of the current controversy on the impact of service screening programmes on ABCR is due to observational data that were gathered and/or analysed with methodological approaches which could not capture stage effects in full. Future research on this important early indicator of screening effectiveness should focus on establishing consensus in the correct methodology.

Experience of pain during mammographic screening by three different compression paddles.

INTRODUCTION: Experience of pain during screening mammography is shown to affect further attendance negatively. We aimed to explore the experience of pain during screening mammography using three different breast compression paddles. METHODS: Using a self-report questionnaire, we collected information on pain experienced during mammography from 938 women screened in Bodø at Nordland Hospital County in 2018, as a part of BreastScreen Norway. Pain was assessed by a numeric rating scale (NRS, 0-10). A fixed paddle, a flexible paddle or a fixed paddle standardizing pressure (study paddle) were used during screening. Compression force (kg) was recorded by the radiographers for each screening examination. Log-binomial regression was used to determine the relative risk (RR) of severe (≥7 on NRS) versus mild/moderate (<7 on NRS) experience of pain associated with type of compression paddle, adjusting for breast tenderness, shoulder(s) and/or neck pain prior to screening, compression force, age, body mass index and screening history. RESULTS: Mean score of self-reported experienced pain was 2.8 for the fixed, 2.3 for the flexible and 2.8 for the study paddle (p < 0.03 for fixed versus flexible and for flexible versus study paddle). Adjusted RR of severe pain was higher for the fixed (RRAdj 2.01, 95%CI 1.13-3.59) and the study paddle (RRAdj 2.52, 95%CI 1.44-4.42) compared to the flexible paddle. Breast tenderness was associated with a higher risk (RRAdj 1.93, 95%CI 1.04-3.58) of severe pain compared to no breast tenderness. CONCLUSION: Women screened with the flexible paddle reported lower experience of pain than those screened with the fixed or study paddle. IMPLICATION FOR PRACTICE: The flexible compression paddle might be the best choice regarding experience of pain in screening mammography. Breast tenderness should be considered by the radiographers in a practical screening setting.

Breast cancer and ductal carcinoma in situ among women with prior squamous or glandular precancer in the cervix: a register-based study.

BACKGROUND: Human papillomavirus and hormonal contraceptives may be risk factors for cervical precancer and malignant breast tumours. METHODS: Standardised incidence ratios (SIRs) of malignant breast tumours during 1970-2008 were estimated separately for women with prior squamous and glandular cervical precancer. RESULTS: Women with squamous precancer and women with glandular precancer in the cervix had a significantly higher risk of malignant breast tumours than the general female population (SIR, 95% confidence interval: 1.10, 1.05-1.14 and 1.52, 1.11-2.08, respectively). INTERPRETATION: Shared risk factors or screening attendance may explain the excess risk of malignant breast tumours among women with a history of cervical precancer.

Standardised or individualised X-ray tube angle for mediolateral oblique projection in digital mammography?

INTRODUCTION: We aimed to investigate whether there were any differences in positioning criteria related to the presentation of the pectoralis major muscle (pectoral muscle) for women of different heights using a standardized 60° X-ray tube angle for mammograms in mediolateral oblique (MLO) projection. METHODS: Data from MLO mammograms of right breasts of 45,193 women screened in BreastScreen Norway 2016-2019 were used. The positioning criteria were related to the pectoral muscle length (measure A and measure B), width and shape and considered adequate or inadequate depending on the degree of fulfilling the criteria. Data associated with the pectoral muscle were extracted from Volpara, an automated software for breast density assessment. Information on height was obtained from a self-reported questionnaire received by the women together with the invitation to attend the screening program. Women were divided into three groups based on the height percentiles (P) in the Norwegian growth curves: < 25th percentile (75th percentile (>P75th: >170 cm). Logistic regression was used to analyse the odds of adequate pectoral muscle length A and B, and shape, adjusting each model for screening technique and equipment model. Results were presented with odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Mean age of the screened women was 61.5 (SD = 4.8) years. The adequate measure for the pectoral muscle length A was obtained for 25.9% (11,724/45,193), length B for 76.3% (34,489/45,193), width for 75.0% (33,894/45,193) and shape for 97.6% (44,118/45,193) of the mammograms. Adjusted odds of an adequate pectoral muscle length A were lower for women of P75th (OR = 1.08, 95% CI 1.02-1.14) compared to women of P25-75. Odds of an adequate pectoral muscle shape were higher for women of P75th (OR = 0.92, 95% CI 0.87-0.97) compared to women of P25-75th. CONCLUSION: The 60° X-ray tube angle might suit most of the female population offered mammographic screening in Norway, but women of a relatively low height (163 cm or lower) might benefit from an X-ray tube angle less than 60-degrees. IMPLICATIONS FOR PRACTICE: Using 60° X-ray tube angle for the MLO mammograms in BreastScreen Norway fit the majority of the participating women. More research is needed to change the protocol associated with the tube angle for women shorter than 163 cm.

Mammographic features and screening outcome in a randomized controlled trial comparing digital breast tomosynthesis and digital mammography.

PURPOSE: To compare the distribution of mammographic features among women recalled for further assessment after screening with digital breast tomosynthesis (DBT) versus digital mammography (DM), and to assess associations between features and final outcome of the screening, including immunohistochemical subtypes of the tumour. METHODS: This randomized controlled trial was performed in Bergen, Norway, and included 28,749 women, of which 1015 were recalled due to mammographic findings. Mammographic features were classified according to a modified BI-RADS-scale. The distribution were compared using 95 % confidence intervals (CI). RESULTS: Asymmetry was the most common feature of all recalls, 24.3 % (108/444) for DBT and 38.9 % (222/571) for DM. Spiculated mass was most common for breast cancer after screening with DBT (36.8 %, 35/95, 95 %CI: 27.2-47.4) while calcifications (23.0 %, 20/87, 95 %CI: 14.6-33.2) was the most frequent after DM. Among women screened with DBT, 0.13 % (95 %CI: 0.08-0.21) had benign outcome after recall due to indistinct mass while the percentage was 0.28 % (95 %CI: 0.20-0.38) for DM. The distributions were 0.70 % (95 %CI: 0.57-0.85) versus 1.46 % (95 %CI: 1.27-1.67) for asymmetry and 0.24 % (95 %CI: 0.16-0.33) versus 0.54 % (95 %CI: 0.43-0.68) for obscured mass, among women screened with DBT versus DM, respectively. Spiculated mass was the most common feature among women diagnosed with non-luminal A-like cancer after DBT and after DM. CONCLUSIONS: Spiculated mass was the dominant feature for breast cancer among women screened with DBT while calcifications was the most frequent feature for DM. Further studies exploring the clinical relevance of mammographic features visible particularly on DBT are warranted.

Breast compression and reported pain during mammographic screening.

INTRODUCTION: We aimed to investigate the association between breast compression and experienced pain during mammographic screening. METHODS: Using a questionnaire, we collected information on pain experienced during mammography from 1155 women screened in Akershus, February-March 2018, as a part of BreastScreen Norway. The questionnaire provided information on pain using a numeric rating scale (NRS, 0-10) and related factors. Data on compression force (Newton, N), pressure (kilopascal, kPa) and breast characteristics were extracted from the DICOM-header and a breast density software. Log-binomial regression was used to determine the relative risk (RR) of severe versus mild/moderate experienced pain associated with compression parameters, adjusting for breast characteristics and related factors. RESULTS: Mean score of experienced pain was 2.2, whereas 6% of the women reported severe pain (≥7) during the examination. High body mass index (BMI) (≥27.3 kg/m2) was associated with a higher RR of pain scores ≥7 (RR 1.86, 95%CI 1.02-3.36) compared to medium BMI (23.7-27.2 kg/m2). Low compression pressure (4.0-10.2 kPa) was associated with a higher RR of severe pain (RR 2.93, 95%CI 1.39-6.20), compared with medium compression pressure (10.3-13.5 kPa) after adjusting for contact area, age, compressed breast thickness, volumetric breast density and BMI. The risk of severe versus mild/moderate pain (≥7 versus <7) decreased by 2% with increasing compression force (RR 0.98, 95%CI 0.97-1.00). CONCLUSION: Women reported low levels of pain during mammography. Further knowledge about factors affecting experienced pain is needed to personalize the examination to the individual woman. IMPLICATIONS FOR PRACTICE: Pain in shoulder(s) and/or neck prior to screening should be considered by the radiographers in a practical screening setting. A compression force of 100-140 N and pressure of 10.3-13.5 kPa are acceptable with respect to reported pain during mammography.

Challenges of informed choice in organised screening.

CONTEXT: Despite much research on informed choice and the individuals' autonomy in organised medical screening, little is known about the individuals' decision-making process as expressed in their own words. OBJECTIVES: To explore the decision-making process among women invited to a mammography screening programme. SETTING: Women living in the counties of Sør- and Nord-Trøndelag, Norway, invited to the first round of the Norwegian Breast Cancer Screening Program (NBCSP) in 2003. METHODS: Qualitative methods based on eight semistructured focus-group interviews with a total of 69 women aged 50-69 years. RESULTS: The decision to attend mammography screening was not based on the information in the invitation letter and leaflet provided by the NBCSP. They perceived the invitation letter with a prescheduled appointment as if a decision for mammography had already been made. This was experienced as an aid in overcoming the postponements that easily occur in daily lives. The invitation to mammography screening was embraced as an indication of a responsible welfare state, "like a mother taking care." CONCLUSION: In a welfare state where governmental institutions are trusted, mass screening for disease is acknowledged by screening participants as a valued expression of paternalism. Trust, gratitude, and convenience were more important factors than information about benefits, harms, and risks when the women made their decisions to attend screening. These elements should be included in the ethical debates on informed choice in preventive medicine.

Mammographic features and histopathological findings of interval breast cancers.

BACKGROUND: Interval cancers are considered a shortcoming in screening mammography due to less favorable prognostic tumor characteristics compared to screening-detected cancers and consequently a lower chance of survival from the disease. PURPOSE: To describe the mammographic features and prognostic histopathological tumor characteristics of interval breast cancers. MATERIAL AND METHODS: A total of 231 interval breast cancer cases diagnosed in prevalently screened women aged 50-69 years old were examined. Thirty-five percent of the cases were retrospectively classified as missed cancers, 23% as minimal sign, and 42% as true negative (including occult cancers) in a definitive classification performed by six experienced breast radiologists. The retrospective classification described the mammographic features of the baseline screening mammograms in missed and minimal-sign interval cancers, while histopathological reports were used to describe the tumor characteristics in all the subgroups of interval cancers. RESULTS: Fifty percent of the missed and minimal-sign interval cancers combined presented poorly defined mass or asymmetric density, and 26% calcifications with or without associated density or mass at baseline screening. Twenty-seven percent of invasive tumors were <15 mm for missed and 47% for true interval cancers (P<0.001). Lymph node involvement was more common in missed (49%) compared with the true cases (33%, P<0.05). CONCLUSION: Missed interval cancers have less prognostically favorable histopathological tumor characteristics compared with true interval cancers. Improving the radiologist's perception and interpretation by establishing systematic collection of features and implementation of organized reviews may decrease the number of interval cancers in a screening program.

Radiographers' opinions on radiography research in Norway - A national survey.

OBJECTIVE: The objective of the Norwegian Radiography Research Group is to establish a strategy for radiography research in Norway. A survey investigating radiographers' opinions on research was conducted to establish a basis for this strategy. METHODS: A questionnaire was sent to all members of the Norwegian Society of Radiographers using the society's e-mail list from May 2014 (n = 2273). The respondents, 31% (n = 697), were divided into six groups; general radiographers (n = 392), specialised radiographers (n = 124), managers (n = 74), radiation therapists (n = 59), professors (n = 13), and others (n = 35). The questionnaire included four parts: introduction, participation in research, research performed at the respondent's work place, and opinions on radiography research. The first parts consisted of close-ended questions, while the fourth part also included a Likert scale. RESULTS: Among all respondents, 63% respondents agreed that there is a need for radiography research and 50% agreed that general radiographers/radiation therapists should be the principal investigators of such research. However, only 19% reported participation in a research project during the last five years, and of those, 50% knew how the results of their research had been communicated. CONCLUSION: The majority of radiographers agreed that there was a need for radiography research and that radiographers/radiation therapists should take a leading role in such work. The results indicate that radiographers/radiation therapists would benefit from training in informal and formal research skills.

Development of a phantom to test fully automated breast density software - A work in progress.

OBJECTIVES: Mammographic density (MD) is an independent risk factor for breast cancer and may have a future role for stratified screening. Automated software can estimate MD but the relationship between breast thickness reduction and MD is not fully understood. Our aim is to develop a deformable breast phantom to assess automated density software and the impact of breast thickness reduction on MD. METHODS: Several different configurations of poly vinyl alcohol (PVAL) phantoms were created. Three methods were used to estimate their density. Raw image data of mammographic images were processed using Volpara to estimate volumetric breast density (VBD%); Hounsfield units (HU) were measured on CT images; and physical density (g/cm3) was calculated using a formula involving mass and volume. Phantom volume versus contact area and phantom volume versus phantom thickness was compared to values of real breasts. RESULTS: Volpara recognized all deformable phantoms as female breasts. However, reducing the phantom thickness caused a change in phantom density and the phantoms were not able to tolerate same level of compression and thickness reduction experienced by female breasts during mammography. CONCLUSION: Our results are promising as all phantoms resulted in valid data for automated breast density measurement. Further work should be conducted on PVAL and other materials to produce deformable phantoms that mimic female breast structure and density with the ability of being compressed to the same level as female breasts. ADVANCES IN KNOWLEDGE: We are the first group to have produced deformable phantoms that are recognized as breasts by Volpara software.

Audit feedback on reading performance of screening mammograms: An international comparison.

OBJECTIVE: Providing feedback to mammography radiologists and facilities may improve interpretive performance. We conducted a web-based survey to investigate how and why such feedback is undertaken and used in mammographic screening programmes. METHODS: The survey was sent to representatives in 30 International Cancer Screening Network member countries where mammographic screening is offered. RESULTS: Seventeen programmes in 14 countries responded to the survey. Audit feedback was aimed at readers in 14 programmes, and facilities in 12 programmes. Monitoring quality assurance was the most common purpose of audit feedback. Screening volume, recall rate, and rate of screen-detected cancers were typically reported performance measures. Audit reports were commonly provided annually, but more frequently when target guidelines were not reached. CONCLUSION: The purpose, target audience, performance measures included, form and frequency of the audit feedback varied amongst mammographic screening programmes. These variations may provide a basis for those developing and improving such programmes.

Women treated with breast conserving surgery do better than those with mastectomy independent of detection mode, prognostic and predictive tumor characteristics.

BACKGROUND: Primary breast conserving treatment (BCT) is well known to have similar long-term survival as mastectomy in breast cancer patients. However, recent studies are suggesting better survival among women treated with BCT compared with mastectomy. More knowledge is needed to understand how disease specific survival is influenced by detection mode, prognostic and predictive tumor characteristics. We aimed to investigate this issue among women targeted by the Norwegian Breast Cancer Screening Program. METHOD: Information about 9547 women aged 50-69 years diagnosed with primary invasive breast cancer without distant metastasis, who underwent either BCT or mastectomy, 2005-2011, were included in the study. Kaplan-Meier plots were used to estimate six years survival, while Cox proportional hazards models were used to estimate the hazard ratio (HR) of breast cancer death associated with surgical treatment. Information about molecular subtype, detection mode, age at diagnosis, tumor size, lymph node involvement, and histologic grade, in addition to radiation treatment, chemotherapy and endocrine therapy were included in adjusted analyses. RESULTS: BCT was performed among 61.9% of the women included in the study. Women treated with BCT had prognostic and predictive favorable tumor characteristics compared to women treated with mastectomy. Adjusted analyses revealed a 1.7 (95% CI: 1.3-2.4) higher risk of breast cancer death among women who underwent mastectomy compared with BCT. CONCLUSION: Women treated with BCT have significantly better breast cancer-specific survival and a lower risk of dying from breast cancer compared to women treated with mastectomy, independent of detection mode, prognostic and predictive tumor characteristic.

The cumulative risk of false-positive screening results across screening centres in the Norwegian Breast Cancer Screening Program.

BACKGROUND: Recall for assessment in mammographic screening entails an inevitable number of false-positive screening results. This study aimed to investigate the variation in the cumulative risk of a false positive screening result and the positive predictive value across the screening centres in the Norwegian Breast Cancer Screening Program. METHODS: We studied 618,636 women aged 50-69 years who underwent 2,090,575 screening exams (1996-2010. Recall rate, positive predictive value, rate of screen-detected cancer, and the cumulative risk of a false positive screening result, without and with invasive procedures across the screening centres were calculated. Generalized linear models were used to estimate the probability of a false positive screening result and to compute the cumulative false-positive risk for up to ten biennial screening examinations. RESULTS: The cumulative risk of a false-positive screening exam varied from 10.7% (95% CI: 9.4-12.0%) to 41.5% (95% CI: 34.1-48.9%) across screening centres, with a highest to lowest ratio of 3.9 (95% CI: 3.7-4.0). The highest to lowest ratio for the cumulative risk of undergoing an invasive procedure with a benign outcome was 4.3 (95% CI: 4.0-4.6). The positive predictive value of recall varied between 12.0% (95% CI: 11.0-12.9%) and 19.9% (95% CI: 18.3-21.5%), with a highest to lowest ratio of 1.7 (95% CI: 1.5-1.9). CONCLUSIONS: A substantial variation in the performance measures across the screening centres in the Norwegian Breast Cancer Screening Program was identified, despite of similar administration, procedures, and quality assurance requirements. Differences in the readers' performance is probably of influence for the variability. This results underscore the importance of continuous surveillance of the screening centres and the radiologists in order to sustain and improve the performance and effectiveness of screening programs.

Stage distribution of breast cancer diagnosed before and after implementation of population-based mammographic screening.

PURPOSE: The German mammographic screening program is very similar to the Norwegian Breast Cancer Screening Program (NBCSP), which started about 10 years earlier. This study analyzes the stage distribution of invasive breast cancers diagnosed in the pre-screening and screening period, and evaluates the overall mortality in women aged 55-74 in the pilot and non-pilot counties of the NBCSP. MATERIALS AND METHODS: The NBCSP invites women aged 50-69 to participate in two-view mammography biennially. Chi-square statistics were used to compare percentages of the stage and treatment of invasive breast cancers diagnosed in women residing in the four pilot counties in the pre-screening (1984-1995) and screening (1996-2007) period. An ecological approach was used to analyze the age-specific mortality in the pilot and non-pilot counties for the period 1970-2007. RESULTS: 50% of the breast cancers diagnosed in the pre-screening period, 70% of the cases detected with screening, 43% of the interval cancers, and 52% of the cancers diagnosed outside the NBCSP were stage I. Stage III+was present in 11% of the cancers in the pre-screening period, and in 1% of the cancers detected with screening. In the screening period, the breast cancer mortality rate decreased substantially more in the pilot counties than in the non-pilot counties. CONCLUSION: The stage distribution of breast cancer diagnosed in the NBCSP is prognostically favorable compared to cancers diagnosed outside the screening program. The reduction in the breast cancer mortality rate was more pronounced in the four pilot counties compared to the non-pilot counties. It is necessary to evaluate the program based on individual data.

Sensitivity and specificity of mammographic screening as practised in Vermont and Norway.

OBJECTIVE: The aim of this study was to examine the sensitivity and specificity of screening mammography as performed in Vermont, USA, and Norway. METHODS: Incident screening data from 1997 to 2003 for female patients aged 50-69 years from the Vermont Breast Cancer Surveillance System (116 996 subsequent screening examinations) and the Norwegian Breast Cancer Screening Program (360 872 subsequent screening examinations) were compared. Sensitivity and specificity estimates for the initial (based on screening mammogram only) and final (screening mammogram plus any further diagnostic imaging) interpretations were directly adjusted for age using 5-year age intervals for the combined Vermont and Norway population, and computed for 1 and 2 years of follow-up, which ended at the time of the next screening mammogram. RESULTS: For the 1-year follow-up, sensitivities for initial assessments were 82.0%, 88.2% and 92.5% for 1-, 2- and >2-year screening intervals, respectively, in Vermont (p=0.022). For final assessments, the values were 73.6%, 83.3% and 81.2% (p=0.047), respectively. For Norway, sensitivities for initial assessments were 91.0% and 91.3% (p=0.529) for 2- and >2-year intervals, and 90.7% and 91.3%, respectively, for final assessments (p=0.630). Specificity was lower in Vermont than in Norway for each screening interval and for all screening intervals combined, for both initial (90.6% vs 97.8% for all intervals; p<0.001) and final (98.8% vs 99.5% for all intervals; p<0.001) assessments. CONCLUSION: Our study showed higher sensitivity and specificity in a biennial screening programme with an independent double reading than in a predominantly annual screening program with a single reading. ADVANCES IN KNOWLEDGE: This study demonstrates that higher recall rates and lower specificity are not always associated with higher sensitivity of screening mammography. Differences in the screening processes in Norway and Vermont suggest potential areas for improvement in the latter.

Patient doses from screen-film and full-field digital mammography in a population-based screening programme.

The aim of this study was to compare mean glandular dose (MGD) in all full-field digital mammography (FFDM) and screen film mammography (SFM) systems used in a national mammography screening program. MGD from 31 screening units (7 FFDM and 24 SFM), based on an average of 50 women at each screening unit, representing 12 X-ray models (6 FFDM and 6 SFM) from five different manufacturers were calculated. The MGD was significantly lower for FFDM compared with SFM (craniocaudal): 1.19 versus 1.27 mGy, respectively, mediolateral oblique: 1.33 versus 1.45 mGy, respectively), but not all of the FFDM units provided lower doses than the SFM units. Comparing FFDMs, the photon counting scanning-slit technology provides significantly lower MGDs than direct and indirect conversion digital technology. The choice of target/filter combination influences the MGD, and has to be optimised with regard to breast thickness.