Comparisons of assessment pathways after abnormal mammography screening in Denmark, Norway, and Spain.

PURPOSE: To ensure high-quality screening programmes and effective utilization of resources, it is important to monitor how cancer detection is affected by different strategies performed at recall assessment. This study aimed to describe procedures performed at recall assessment and compare and evaluate the performance of the assessment in Denmark, Norway, and Spain in terms of screen-detected cancer (SDC) and interval cancer (IC) rates. METHODS: We included women aged 50-69 years from Denmark, Norway, and Spain, who were recalled for assessment after screening mammography, and recorded all procedures performed during six months after diagnosis, and the timing of the procedures. Women were followed for two years and screen-detected and interval cancer, and sensitivity of recall was calculated and compared. RESULTS: In total, data from 24,645 Danish, 30,050 Norwegian, and 41,809 Spanish women were included in the study. Most of the women had some assessment within 2 months in all three countries. SDC rates were higher in Denmark (0.57) and Norway (0.60) compared to Spain (0.38), as were the IC rates, i.e. 0.25 and 0.18 vs. 0.12, respectively. The sensitivity of the diagnostic follow-up was somewhat higher in Denmark (98.3%) and Norway (98.2%), compared to Spain (95.4%), but when excluding non-invasive assessment pathways, the sensitivities were comparable. CONCLUSION: This comparison study showed variation in the assessment procedures used in the three countries as well as the SDC and IC rates and the sensitivity of recall.

Personalized Breast Cancer Screening: A Risk Prediction Model Based on Women Attending BreastScreen Norway.

BACKGROUND: We aimed to develop and validate a model predicting breast cancer risk for women targeted by breast cancer screening. METHOD: This retrospective cohort study included 57,411 women screened at least once in BreastScreen Norway during the period from 2007 to 2019. The prediction model included information about age, mammographic density, family history of breast cancer, body mass index, age at menarche, alcohol consumption, exercise, pregnancy, hormone replacement therapy, and benign breast disease. We calculated a 4-year absolute breast cancer risk estimates for women and in risk groups by quartiles. The Bootstrap resampling method was used for internal validation of the model (E/O ratio). The area under the curve (AUC) was estimated with a 95% confidence interval (CI). RESULTS: The 4-year predicted risk of breast cancer ranged from 0.22-7.33%, while 95% of the population had a risk of 0.55-2.31%. The thresholds for the quartiles of the risk groups, with 25% of the population in each group, were 0.82%, 1.10%, and 1.47%. Overall, the model slightly overestimated the risk with an E/O ratio of 1.10 (95% CI: 1.09-1.11) and the AUC was 62.6% (95% CI: 60.5-65.0%). CONCLUSIONS: This 4-year risk prediction model showed differences in the risk of breast cancer, supporting personalized screening for breast cancer in women aged 50-69 years.

Screening outcome for interpretation by the first and second reader in a population-based mammographic screening program with independent double reading.

BACKGROUND: Double reading of screening mammograms is associated with a higher rate of screen-detected cancer than single reading, but different strategies exist regarding reader pairing and blinding. Knowledge about these aspects is important when considering strategies for future use of artificial intelligence in mammographic screening. PURPOSE: To investigate screening outcome, histopathological tumor characteristics, and mammographic features stratified by the first and the second reader in a population based screening program for breast cancer. MATERIAL AND METHODS: The study sample consisted of data from 3,499,048 screening examinations from 834,691 women performed during 1996-2018 in BreastScreen Norway. All examinations were interpreted independently by two radiologists, 272 in total. We analyzed interpretation score, recall, and cancer detection, as well as histopathological tumor characteristics and mammographic features of the cancers, stratified by the first and second readers. RESULTS: For Reader 1, the rate of positive interpretations was 4.8%, recall 2.3%, and cancer detection 0.5%. The corresponding percentages for Reader 2 were 4.9%, 2.5%, and 0.5% (P < 0.05 compared with Reader 1). No statistical difference was observed for histopathological tumor characteristics or mammographic features when stratified by Readers 1 and 2. Recall and cancer detection were statistically higher and histopathological tumor characteristics less favorable for cases detected after concordant positive compared with discordant interpretations. CONCLUSION: Despite reaching statistical significance, mainly due to the large study sample, we consider the differences in interpretation scores, recall, and cancer detection between the first and second readers to be clinically negligible. For practical and clinical purposes, double reading in BreastScreen Norway is independent.

Screen-detected and interval breast cancer after concordant and discordant interpretations in a population based screening program using independent double reading.

OBJECTIVES: To analyze rates, odds ratios (OR), and characteristics of screen-detected and interval cancers after concordant and discordant initial interpretations and consensus in a population-based screening program. METHODS: Data were extracted from the Cancer Registry of Norway for 487,118 women who participated in BreastScreen Norway, 2006-2017, with 2 years of follow-up. All mammograms were independently interpreted by two radiologists, using a score from 1 (negative) to 5 (high suspicion of cancer). A score of 2+ by one of the two radiologists was defined as discordant and 2+ by both radiologists as concordant positive. Consensus was performed on all discordant and concordant positive, with decisions of recall for further assessment or dismiss. OR was estimated with logistic regression with 95% confidence interval (CI), and histopathological tumor characteristics were analyzed for screen-detected and interval cancer. RESULTS: Among screen-detected cancers, 23.0% (697/3024) had discordant scores, while 12.8% (117/911) of the interval cancers were dismissed at index screening. Adjusted OR was 2.4 (95% CI: 1.9-2.9) for interval cancer and 2.8 (95% CI: 2.5-3.2) for subsequent screen-detected cancer for women dismissed at consensus compared to women with concordant negative scores. We found 3.4% (4/117) of the interval cancers diagnosed after being dismissed to be DCIS, compared to 20.3% (12/59) of those with false-positive result after index screening. CONCLUSION: Twenty-three percent of the screen-detected cancers was scored negative by one of the two radiologists. A higher odds of interval and subsequent screen-detected cancer was observed among women dismissed at consensus compared to concordant negative scores. Our findings indicate a benefit of personalized follow-up. KEY POINTS: • In this study of 487,118 women participating in a screening program using independent double reading with consensus, 23% screen-detected cancers were detected by only one of the two radiologists. • The adjusted odds ratio for interval cancer was 2.4 (95% confidence interval: 1.9, 2.9) for cases dismissed at consensus using concordant negative interpretations as the reference. • Interval cancers diagnosed after being dismissed at consensus or after concordant negative scores had clinically less favorable prognostic tumor characteristics compared to those diagnosed after false-positive results.

Factors associated with attendance and attendance patterns in a population-based mammographic screening program.

OBJECTIVE: To explore the factors associated with attendance and attendance pattern in BreastScreen Norway. METHODS: We evaluated the number of invitations (n = 1,253,995) and attendances, 2015-2019, stratified by age, invitation method, screening unit and time of appointment. Attendance pattern was analysed for women invited 10 times (n = 47,979), 1996-2019. The association of education level, body mass index, physical activity and smoking status with attendance was analysed for a sub-sample of women (n = 37,930). Descriptive statistics were used to analyse attendance, and negative binomial regression was used to analyse the association between the total number of attendances and education level and lifestyle factors. RESULTS: The attendance rate was 76.0%, 2015-2019. The rate was 78.0% for women aged >64 and 73.9% for those <55 . We found a rate of 82.0% for women who received a digital invitation, while it was 73.7% for those invited by post. The rate was 78.1% for invitations in the late afternoon, 3-6 p.m., while later appointments reached a rate of 73.7%. Half of the women invited 10 times attended all times. The predicted total number of attendances was 9 out of 10 for the factors investigated. CONCLUSION: The highest attendance rates were shown for women aged >64, those who received digital invitations and those having appointments in late afternoon. The differences in predicted number of attendances between the investigated factors were minor. Overall, BreastScreen Norway has a high attendance rate. However, efforts aimed at increasing the attendance in specific groups should be considered.

Validity and reliability of self-reported health indicators among women attending organized mammographic screening.

AIMS: Risk factors for breast cancer are often used for adjustment in epidemiological studies, including in the evaluation of early performance measures in mammographic screening. Information about risk factors among participants in the Norwegian Breast Cancer Screening Program has been collected since 2006. We aimed to examine the validity of self-reported history of breast cancer and mammographic screening, as well as the reliability of weight and height amongt women attending the program. METHODS: Information from a questionnaire handed in by participants in the program, 2006-2015, was linked to outcomes from the Cancer Registry of Norway. Sensitivity, specificity, and positive predictive values (PPV) were calculated for self-reported histories of breast cancer and screening. Results were stratified by five-year age groups and evaluated using the χ2 statistic. The reliability of self-reported weight and height were assessed using descriptive statistics, histograms, and mean differences. RESULTS: A total of 538,907 of 611,711 (88%) women attending the program during the study period returned at least one part of the questionnaire. The overall sensitivity, specificity, and PPV for breast cancer and mammography were 96.5%, 99.8%, and 81.3%; and 99.9%, 84.4%, and 97.6% respectively. The mean difference in self-reported weight was 0.35 kg and for height was -0.14 cm, over a period of up to 10 years. CONCLUSIONS: Norwegian women attending the screening program are reasonably accurate in self-reporting their breast cancer and mammography histories. On average, women consistently reported weight and height within one kg/cm.

Interval Breast Cancer Rates and Histopathologic Tumor Characteristics after False-Positive Findings at Mammography in a Population-based Screening Program.

Purpose To compare rates and tumor characteristics of interval breast cancers (IBCs) detected after a negative versus false-positive screening among women participating in the Norwegian Breast Cancer Screening Program. Materials and Methods The Cancer Registry Regulation approved this retrospective study. Information about 423 445 women aged 49-71 years who underwent 789 481 full-field digital mammographic screening examinations during 2004-2012 was extracted from the Cancer Registry of Norway. Rates and odds ratios of IBC among women with a negative (the reference group) versus a false-positive screening were estimated by using logistic regression models adjusted for age at diagnosis and county of residence. Results A total of 1302 IBCs were diagnosed after 789 481 screening examinations, of which 7.0% (91 of 1302) were detected among women with a false-positive screening as the most recent breast imaging examination before detection. By using negative screening as the reference, adjusted odds ratios of IBCs were 3.3 (95% confidence interval [CI]: 2.6, 4.2) and 2.8 (95% CI: 1.8, 4.4) for women with a false-positive screening without and with needle biopsy, respectively. Women with a previous negative screening had a significantly lower proportion of tumors that were 10 mm or less (14.3% [150 of 1049] vs 50.0% [seven of 14], respectively; P < .01) and grade I tumors (13.2% [147 of 1114] vs 42.9% [six of 14]; P < .01), but a higher proportion of cases with lymph nodes positive for cancer (40.9% [442 of 1080] vs 13.3% [two of 15], respectively; P = .03) compared with women with a previous false-positive screening with benign biopsy. A retrospective review of the screening mammographic examinations identified 42.9% (39 of 91) of the false-positive cases to be the same lesion as the IBC. Conclusion By using a negative screening as the reference, a false-positive screening examination increased the risk of an IBC three-fold. The tumor characteristics of IBC after a negative screening were less favorable compared with those detected after a previous false-positive screening. © RSNA, 2017 Online supplemental material is available for this article.

Monthly variation in mammographic screening attendance in Norway.

Breast Cancer Awareness Month (BCAM) increases screening attendance in the USA. However, this effect has not been investigated in Europe, where organized screening is widespread. We examined monthly attendance within the Norwegian Breast Cancer Screening Programme, 2005-15. Relative to October, the odds of attending screening in January, February, March, August, September or December were slightly decreased (ORadj 0.93-0.98, P ≤ 0.003 for all). BCAM may marginally increase attendance in October but seasonal factors such as weather may also explain this observed variation. Furthermore, it is possible that organized screening with predetermined appointments evens out the effect BCAM has on screening attendance.

[Attendance in the Norwegian Breast Cancer Screening Programme]. / Oppmøte i Mammografiprogrammet.

BACKGROUND: A high rate of attendance among women invited to the Norwegian Breast Cancer Screening Programme (NBCSP) is essential to achieve optimal effect, including reduction in breast cancer mortality. This article describes attendance in the programme by county, period and women's age at invitation. MATERIAL AND METHOD: All women in the age group 50 ­ 69 years who are registered in the National Population Register are invited to attend the NBCSP every second year. In the study period 2007 ­ 2014, 2 142 369 invitations were sent, and 1 600 293 screening examinations were performed for 710 169 women. Use of the data is pursuant to the Cancer Registry Regulations. RESULTS: Altogether 84 % of the women invited attended at least once in the study period. The average attendance rate per screening round was 75 %. In Rogaland, Nordland and Sogn og Fjordane counties more than 80 % attended, while in Oslo the figure was 62 %. The highest rate of attendance recorded was for women in the age group 62 ­ 67 years. The attendance in the prior screening round was of influence for reattendance. INTERPRETATION: The mammography screening programme has a high level of acceptance among women in the target group. Possible reasons for the variation in attendance among the county districts should be identified.