Population-based Mammography Screening Program Research Articles

Structured screening for sporadic breast cancer

The aim of secondary prevention of breast cancer is to detect the disease at the earliest curable stage and thus to reduce breast cancer-specific mortality. To this end, the nationwide population-based mammography screening program (MSP) was set up in Germany in 2005 in addition to an interdisciplinary prevention project for high-risk groups. Overview of the current state of the MSP, the upcoming age expansion, and potential further developments. Narrative review article with topic-guided literature and data search. Approximately 50% of the 70,500 new cases of breast cancer that occur each year are related to the age group of the MSP. 10years after introduction of the MSP, the incidence of advanced breast cancer stages and breast cancer-related mortality of the screening target group have steadily decreased by about one quarter, while no relevant trends were seen in the neighboring age groups at the population level. The MSP has effectively contributed to areduction of breast cancer mortality. With the expansion of the age groups to 45-75years, more women have access to structured, quality assured screening. With the use of advanced stratifications and diagnostics as well as artificial intelligence, the MSP could be further optimized.

Age-specific differences in tumour characteristics between screen-detected and non-screen-detected breast cancers in women aged 40-74 at diagnosis in Sweden from 2008 to 2017.

To analyze differences between screen-detected and non-screen-detected invasive breast cancers by tumour characteristics and age at diagnosis in the nationwide population-based mammography screening program in Sweden. Data were retrieved from the National Quality Register for Breast Cancer for 2008-2017. Logistic regression analysis was used to estimate the likelihood for a tumour to be screen-detected by tumour characteristics and age group at diagnosis. In total there were 51,429 invasive breast cancers in the target age group for mammography screening of 40-74 years. Likelihood of screen detection decreased with larger tumour size, lymph node metastases, higher histological grade and distant metastasis. Odds ratios (ORs) for negative oestrogen (ER) and progesterone (PgR) were 0.41 and 0.57; for positive HER2, 0.62; for Ki-67 high versus low, 0.49. Molecular sub-types had OR of 0.56, 0.40 and 0.28, respectively, for luminal B-like, HER2-positive and triple negative versus luminal A-like. Adjusting for tumour size (T), lymph node status (N), age, year and county at diagnosis slightly elevated the ORs. Statistically significant interactions between tumour characteristics and age were found (p < 0.05) except for ER and PgR. The age group 40-49 deviated most from the other age groups. Our study demonstrates that screen-detected invasive breast cancers had more favourable tumour characteristics than non-screen-detected after adjusting for age, year and county of diagnosis, and even after adjusting for T and N. The trend towards favourable tumour characteristics was less pronounced in the 40-49 age group compared to the other age groups, except for ER and PgR.

Prevalence of women with breast implants in Sweden: a study based on the population-based mammography screening programme.

Knowledge about the prevalence of women with breast implants is paramount in calculations of risks and in estimations of effects on screening and breast cancer treatment. Most of the estimations of prevalence made to date are rough and often based on sales data. The main aim of this study was to calculate the prevalence of breast implants in Swedish women. The secondary aim was to investigate if it is feasible to establish the occurrence of breast implants with the help of the public mammography screening programme, in a country with a publicly funded welfare-type healthcare system and with a clear documentation of screening. Information on implants was prospectively collected from all screening attendants from 1st of February 2022 to 1st of August 2022 based on a question from the radiographer to the woman and later verified on the mammogram. During the study period 4,639 women were screened, of which 182 had implants (3.9%). The frequency varies between 1.6 and 6.4% in different age groups. The prevalence of breast implants in Swedish women is estimated to be around 4%. The population-based mammography screening programme in countries with a publicly funded welfare-type healthcare system and a clear documentation of mammography screening attendance, seems to be a feasible way to establish the prevalence of breast implants in the population. The large number of women with breast implants warrants further studies regarding the best diagnostic and treatment alternatives for this group. Pre-registration: ClinicalTrials.Gov identifier NCT05222100.

The effect of a pre-scheduled appointment on attendance in a population-based mammography screening programme.

Pre-scheduled appointments can increase attendance in breast cancer screening programmes compared to 'open invitations' but relatively few randomized controlled trials exist. We investigated the effect of a pre-scheduled appointment on uptake in the Flemish population-based mammography screening programme. Between September and December 2022, a total of 4798 women were randomly assigned to receive either a pre-scheduled appointment or open invitation. The difference in attendance was compared with Poisson regression analysis for the primary endpoint (attendance ≤92 days after date of invitation), yielding relative risks (RRs). This was done separately for three groups: women invited to a mobile unit and a history of nonattendance (group M-NA); women invited to a hospital-based unit and a history of nonattendance (group HB-NA); women invited to a hospital-based unit and a history of irregular attendance (group HB-IA). There were no women invited to a mobile unit and a history of irregular attendance. The RRs in favour of the pre-scheduled appointment were 2.3 [95% confidence interval (CI) 1.80-2.88], 1.8 (95% CI 1.07-2.97) and 1.8 (95% CI 1.43-2.39), for groups M-NA, HB-NA and HB-IA, respectively. We found no statistically significant difference between the various RRs. The respective absolute gains in attendance between pre-scheduled appointment and open invitation were 8.3%, 4.4% and 15.8%. Sending an invitation with a pre-scheduled appointment is an effective tool to increase screening attendance in both mobile and hospital-based screening units. The pre-scheduled appointment is associated with a considerable absolute gain in attendance which varies depending on the screening history.

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

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. 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. 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. 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. 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.

The effect of the Flemish breast cancer screening program on breast cancer-specific mortality: A case-referent study

BackgroundBreast cancer screening programs were introduced in many countries worldwide following randomized controlled trials in the 1980s showing a reduction in breast cancer-specific mortality. However, their effectiveness remains debated and estimates vary. A breast cancer screening program was introduced in 2001 in Flanders, Belgium where high levels of opportunistic screening practices are observed. The effectiveness of this program was estimated by measuring its effect on breast cancer-specific mortality. MethodsWe performed a case-referent study to investigate the effect of participation in the Flemish population-based mammography screening program (PMSP) on breast cancer-specific mortality from 2005 to 2017. A multiple logistic regression model assessed the association between breast cancer-specific death and screening program participation status in the four years prior to (pseudo)diagnosis (yes/no), with adjustment for potential confounders (individual socio-economic position and calendar year of diagnosis) and stratified for age. In addition, we performed different sensitivity analyses. ResultsWe identified 1571 cases and randomly selected 6284 referents. After adjustment, women who participated in PMSP had a 51 % lower risk of breast cancer-specific mortality compared to those who did not (adjusted odds ratio [aOR] =0.49, 95 % CI: 0.44–0.55). Sensitivity analyses did not markedly change the estimated associations. Correction for self-selection bias reduced the effect size, but the estimate remained significant. ConclusionOur results indicate that in a context of high opportunistic screening rates, participation in breast cancer screening program substantially reduces breast cancer-specific mortality. For policy, these results should be balanced against the potential harms of screening, including overdiagnosis and overtreatment.

The impact of breast density notification on rescreening rates within a population-based mammographic screening program

BackgroundHigh participation in mammographic screening is essential for its effectiveness to detect breast cancers early and thereby, improve breast cancer outcomes. Breast density is a strong predictor of breast cancer risk and significantly reduces the sensitivity of mammography to detect the disease. There are increasing mandates for routine breast density notification within mammographic screening programs. It is unknown if breast density notification impacts the likelihood of women returning to screening when next due (i.e. rescreening rates). This study investigates the association between breast density notification and rescreening rates using individual-level data from BreastScreen Western Australia (WA), a population-based mammographic screening program.MethodsWe examined 981,705 screening events from 311,656 women aged 40+ who attended BreastScreen WA between 2008 and 2017. Mixed effect logistic regression was used to investigate the association between rescreening and breast density notification status.ResultsResults were stratified by age (younger, targeted, older) and screening round (first, second, third+). Targeted women screening for the first time were more likely to return to screening if notified as having dense breasts (Percentunadjusted notified vs. not-notified: 57.8% vs. 56.1%; Padjusted = 0.016). Younger women were less likely to rescreen if notified, regardless of screening round (all P < 0.001). There was no association between notification and rescreening in older women (all P > 0.72).ConclusionsBreast density notification does not deter women in the targeted age range from rescreening but could potentially deter younger women from rescreening. These results suggest that all breast density notification messaging should include information regarding the importance of regular mammographic screening to manage breast cancer risk, particularly for younger women. These results will directly inform BreastScreen programs in Australia as well as other population-based screening providers outside Australia who notify women about breast density or are considering implementing breast density notification.

Population-based mammography screening attendance in Sweden 2017–2018: A cross-sectional register study to assess the impact of sociodemographic factors

Sweden has a population-based mammography screening programme for women aged 40–74. The objective of this study was to examine the association between mammography screening attendance and sociodemographic factors in 15 of Sweden's 21 health care regions. Register-based information was collected on all mammography screening invitations and attendance during 2017 and 2018, and linked to individual-level sociodemographic data from Statistics Sweden. Odds ratios (ORs) and 95% confidence intervals (CIs) for attendance were computed by sociodemographic factor. The study sample included 1.5 million women, aged 40–75, with an overall screening attendance of 81.3%. The lowest odds of attending were found for women living without a partner (OR = 0.52, 95% CI: 0.52–0.53), low-income women (OR = 0.57, 95% CI: 0.56–0.57), and non-Nordic women born in Europe (OR = 0.60, 95% CI: 0.59–0.61). Other groups with lower odds of attending were women whose main source of income was social assistance or benefits (OR = 0.62, 95% CI: 0.62–0.63), those not owning their home (OR = 0.66, 95% CI: 0.66–0.67), and those with low level of education (OR = 0.72, 95% CI: 0.71–0.73). Having multiple of these sociodemographic characteristics further lowered the odds of attending. Although overall mammography screening attendance in Sweden is high, sociodemographic inequalities exist, and efforts should be made to address these. Particular attention should be given to low-income women who live without a partner.

Post-mammographic screening behaviour: A survey investigating what women do after being told they have dense breasts.

Despite widespread calls for women undergoing mammographic screening to be informed of their breast density, concerns remain as to how this is interpreted and acted upon given the absence of evidence-based supplemental screening recommendations for women with dense breasts. This study investigates the action women take in response to being notified they have dense breasts and what subsequent advice women receive from health professionals. Via a survey of nearly 7000 women, we assessed the post-screening actions of women attending a population-based mammographic screening program (BreastScreen) in Western Australia from 21 November 2017 to 19 April 2018. Women who reported that they were notified they had dense breasts were compared to controls (where applicable). Descriptive and logistic regression analyses were used to summarise responses from 6,183 women. Half of women notified that they have dense breasts consulted or intended to consult their General Practitioner (GP), particularly those notified for the first time (55%). Of those notified women who consulted their GP, 50% were referred to have supplemental screening. Overall, 20% of women notified as having dense breasts reported that they had an ultrasound due to their breast density. Self-reported health service usage after mammographic screening is higher in women who have been notified they have dense breasts. So what? There is growing pressure for screening programs in Australia and internationally to routinely measure and report breast density to participants. Results from this study can inform screening programs of the likely impact of breast density notification on health service usage. While more information is needed to fill knowledge gaps in recommended action for women with dense breasts, the greatest risks to women arise from not being screened. Hence, health promotion practitioners and health providers should continue to encourage women to participate in BreastScreen programs.

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

To explore the factors associated with attendance and attendance pattern in BreastScreen Norway. 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. 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. 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.

Incidence of advanced-stage breast cancer in regular participants of a mammography screening program: a prospective register-based study

BackgroundThe European Guidelines for breast cancer screening suggest that the impact of population-based mammography screening programmes (MSP) may be assessed using the relative reduction in the incidence of advanced breast cancer (ABC, that is, stage UICC II and higher) as a surrogate indicator of screening effectiveness.MethodsThis prospective, population register-based study contained individual data of 1,200,246 women (aged 50–69 years) who attended the initial prevalence screening between 2005 and 2009. Of them, 498,029 women returned for the regular (i.e., within 24 months) first subsequent, and 208,561 for the regular second subsequent incidence screenings. The incidence rate of ABC was calculated for the 24-months period following, but not including, the initial screening by incorporating all interval ABCs and all ABCs detected at the regular first incidence screening; the ABC rate for the second 24-months period was determined in the same way, including ABCs detected in the interval after the first and, respectively, at the second incidence screening. The relative reduction in the ABC incidence was derived by comparing the age-standardized rates in these two periods with an age-standardized reference incidence rate, observed in the target population before the MSP implementation. The strengths and weaknesses of this particular study design were contrasted with a recently published checklist of main methodological problems affecting studies of the effect of MSP on ABC incidence.ResultsThe age-standardized ABC incidence rate was 291.6 per 100,000 women for the 24-months period subsequent to the initial screening, and 275.0/100,000 for the 24-months period following the first subsequent screening. Compared to the 2-year incidence of 349.4/100,000 before the start of the MSP, this amounted to a relative reduction of 16.5 and 21.3%, respectively, in the incidence of ABC among regular MSP participants.ConclusionsThe design employed in this study avoids some of the substantial methodological limitations that compromised previous observational studies. Nevertheless, specific limitations prevail that demand a cautious interpretation of the results. Therefore, the study findings, indicating a reduction in ABC for regular MSP participants, need to be followed with respect to potential impacts on breast cancer mortality rates.

Readmissions and complications in breast ductal carcinoma in situ: A retrospective study comparing screen- and non-screen-detected patients.

Objective:Population-wide mammographic screening programs aim to reduce breast cancer mortality. However, a broad view of the harms and benefits of these programs is necessary to favor informed decisions, especially in the earliest stages of the disease. Here, we compare the outcomes of patients diagnosed with breast ductal carcinoma in situ in participants and non-participants of a population-based mammographic screening program.Methods:A retrospective cohort study of all patients diagnosed with breast ductal carcinoma in situ between 2000 and 2010 within a single hospital. A total of 211 patients were included, and the median follow-up was 8.4 years. The effect of detection mode (screen-detected and non-screen-detected) on breast cancer recurrences, readmissions, and complications was evaluated through multivariate logistic regression analysis.Results:In the majority of women, breast ductal carcinoma in situ was screen-detected (63.5%). Screen-detected breast ductal carcinoma in situ was smaller in size compared to those non-screen-detected (57.53% < 20 mm versus 78.03%, p = 0.002). Overall, breast-conserving surgery was the most frequent surgery (86.26%); however, mastectomy was higher in non-screen-detected breast ductal carcinoma in situ (20.78% versus 9.7%, p = 0.024). Readmissions for mastectomy were more frequent in non-screen-detected breast ductal carcinoma in situ. Psychological complications, such as fatigue, anxiety, and depression, had a prevalence of 15% within our cohort. Risk of readmissions and complications was higher within the non-screen-detected group, as evidenced by an odds ratio = 6.25 (95% confidence interval = 1.95–19.99) for readmissions and an odds ratio = 2.41 (95% confidence interval = 1.95–4.86) for complications.Conclusions:Our findings indicate that women with breast ductal carcinoma in situ breast cancer diagnosed through population-based breast cancer screening program experience a lower risk of readmissions and complications than those diagnosed outside these programs. These findings can help aid women and health professionals make informed decisions regarding screening.

Flemish breast cancer screening programme: 15\u2009years of key performance indicators (2002\u20132016)

BackgroundWe examined 15 years of key performance indicators (KPIs) of the population-based mammography screening programme (PMSP) in Flanders, Belgium.MethodsIndividual screening data were linked to the national cancer registry to obtain oncological follow-up. We benchmarked crude KPI results against KPI-targets set by the European guidelines and KPI results of other national screening programmes. Temporal trends were examined by plotting age-standardised KPIs against the year of screening and estimating the Average Annual Percentage Change (AAPC).ResultsPMSP coverage increased significantly over the period of 15 years (+ 7.5% AAPC), but the increase fell to + 1.6% after invitation coverage was maximised. In 2016, PMSP coverage was at 50.0% and opportunistic coverage was at 14.1%, resulting in a total coverage by screening of 64.2%. The response to the invitations was 49.8% in 2016, without a trend. Recall rate decreased significantly (AAPC -1.5% & -5.0% in initial and subsequent regular screenings respectively) while cancer detection remained stable (AAPC 0.0%). The result was an increased positive predictive value (AAPC + 3.8%). Overall programme sensitivity was stable and was at 65.1% in 2014.In initial screens of 2015, the proportion of DCIS, tumours stage II+, and node negative invasive cancers was 18.2, 31.2, and 61.6% respectively. In subsequent regular screens of 2015, those proportions were 14.0, 24.8, and 65.4% respectively. Trends were not significant.ConclusionBesides a suboptimal attendance rate, most KPIs in the Flemish PMSP meet EU benchmark targets. Nonetheless, there are several priorities for further investigation such as a critical evaluation of strategies to increase screening participation, organising a biennial radiological review of interval cancers, analysing the effect that preceding opportunistic screening has on the KPI for initial screenings, and efforts to estimate the impact on breast cancer mortality.

Trends in surgical treatment for breast cancer in Germany after the implementation of the mammography screening program.

In Germany, the nationwide population-based mammography screening program (MSP) was introduced in 2005 and is full-running since 2010. By 2014, incidence rates for invasive breast cancer were very similar to those of the pre-screening era. Therefore, the ongoing effect of the MSP on breast cancer surgery rates can now be investigated. We analyzed population-based breast-conserving (BCS) and mastectomy (MET) surgery rates (per 100,000) among women aged < 50, 50-69 (eligible for the MSP), and 70+ years among women with in situ and invasive breast cancer during 2005-2015. For invasive breast cancer, both BCS and MET rates slightly increased in the age group < 50years (38.3 in 2005 vs 42.5 in 2015 and 15.7 vs 18.2, respectively). In contrast, MET rates considerably decreased among women aged 50-69 and 70+ years (92 vs 65.4 and 155.4 vs 122.1, respectively), while BCS rates increased in both age groups (210.6 vs 254.4 and 147.2 vs 187, respectively). For in situ breast cancer, MET rates slightly increased in all age groups. BCS rates slightly increased in women aged < 50, but nearly doubled for women aged 50-69 (26.9 vs 49.1) and markedly increased in the 70+ age group (11.5 vs 16.1). During and after the implementation of MSP, there was a strong shift towards BCS within the screening-eligible age group and for women aged 70+ . Women with invasive breast cancer in these age groups may profit from screening with a decline of MET rates in favor of BCS rates at the expense of higher surgery rates for in situ breast cancer.

Evidence based mammography screening: is evidence changing?

Population-based mammography screening programmes were launched by developed countries in the latter half of the twentieth century based on the promising evidence on mortality benefits reported by the earliest randomised control trials (RCTs). It was widely accepted that screening mammography significantly reduced breast cancer mortality in women invited for screening. However, since the first RCT in the 1960s, varying evidence has been tabled by many researchers, sometimes alarming the public, drawing attention to the harms of screening mammography, mainly identified as overdiagnosis and false positives. While overtreatment is recognised as a consequence of over diagnosis, a relatively newer set of harms categorized under psychological distress have been highlighted as resultant from false positive screening tests. Currently, the magnitude of the harms of screening mammography remains uncertain. The most turbulent reviews on breast screening, however, were the queries into the well and long believed mortality benefits of mammography screening first tabled in the 1970s by the Canadian national breast screening study. A Cochrane review by Gotzsche and Jorgensen further added to the negative attributes of mammography screening as they concluded that the actual current mortality benefits are nonsignificant and smaller than that claimed by many RCTs which were poorly randomised. Although heavily criticized, sparks ignited by these reports have led many countries worldwide to conduct their panel discussions on evidence on population screening mammography. While many countries have decided to continue their programmes understanding the harms involved, Switzerland in this light has discontinued their population-based mammography screening programme. The debate continues; currently while not overlooking the mortality benefits of mammography, it is also understood that the mortality benefits are not solely due to mammography but are also contributed by other factors such as advancement in therapeutic measures and awareness on breast cancer created among the females. In this regard, critical evaluation of global literature is imperative to make country-specific policy decisions for middle-income countries such as Sri Lanka, who are contemplating the options for expanding opportunistic mammography screening services to reach wider population screening targets.

Knowledge about mammography screening in Germany by education and migrant status \u2013 results of a cross-sectional study (InEMa)

BackgroundThe population-based mammography screening program (MSP) is aimed to reduce breast cancer mortality, to detect breast cancer at an early stage, and to allow for less invasive treatment. However, it also has some potential harms, such as overdiagnosis and overtreatment. Therefore, it is necessary that women receive sufficient and balanced information to enable informed decision-making. We examined knowledge about benefits and harms of the MSP in Germany among first-time invitees of different socio-demographic backgrounds.MethodsThis observational study assessed knowledge about benefits and harms of the MSP among women who were invited to the MSP for the first time by six multiple choice items, using a postal survey. We investigated (i) single items of knowledge, (ii) the distribution of sufficient knowledge stratified by education, migration status and invitation, and (iii) possible determinants of sufficient knowledge by analyzing Odds Ratios (ORs) using bivariate and multivariate logistic regression.ResultsIn total, 5397 women included in the analyses. 46.1% of the study population had sufficient knowledge about benefits and harms of the MSP. However, women with low educational level and migration background had higher proportions of insufficient knowledge and used most frequently the option “don’t know”. Women had the most difficulties answering the numeric question and the question about the target group correctly. Results from the logistic regression showed that the odds of having sufficient knowledge were higher among well-educated women (OR 3.84, 95%CI 3.24–4.55), among women who already received the MSP invitation (OR 1.38, 95%CI 1.20–1.59) and lowest among Turkish women (OR 0.14, 95%CI 0.07–0.25).ConclusionsWomen with low education and migration background need adapted information regarding benefits and harms of the MSP and are important target groups for further developing the information material about mammography screening to reduce disparities in knowledge and enable informed decision-making.

Abstract P4-02-02: Outcomes of diagnostic surgical biopsy in a population-based mammographic screening program

Abstract Background: Screening mammography allows earlier diagnosis of breast cancer resulting in reduced breast cancer specific mortality, and potentially reduced morbidity from less intense treatment. These benefits may be offset by investigation and treatment of lesions that are detected on screening but which are eventually found to be clearly benign, have uncertain malignant potential, or are malignant but pose no threat to the person during her natural life. Abnormalities detected on screening mammograms are recalled for further assessment. The outcomes of assessment may be confirmation of the absence suspicious findings. It may be a core biopsy is performed to clarify the nature of a persistently indeterminate or suspicious lesion. In cases when workup has neither diagnosed malignancy nor excluded its possibility, diagnostic surgical biopsy (DSB) is recommended. DSB of a lesion where final pathology is benign is a harm from a screening program. The benefit of DSB where a core needle biopsy (CNB) has shown a high-risk lesion is dependent on identifying more significant pathology than that of the CNB. Trials are currently recruiting which investigate a non-operative approach for DCIS, yet DSB is still standard of care for less significant/benign pathologies in much of the world. We aimed to determine the outcomes for patients recommended for DSB in a population-based mammographic screening program in order to identify situations in which this may safely be omitted. Methods: Ethics approval was obtained through Melbourne Health. Cases of DSB were reviewed from Northwest BreastScreen and Southern BreastScreen in Melbourne, Australia. Registry data was extracted including all patients where recommendation for DSB was made over a ten-year period (January 2004- December 2013). Patient demographics, imaging characteristics, core biopsy &amp; surgical pathology were reviewed manually from individual BreastScreen files. Data points were entered to an Excell database. We reviewed assessment reports, tabulated indications for DSB, and surgical pathology reports for final histopathology. Results: 1286 patients underwent DSB over the ten-year period. The overall upgrade rate to malignancy on DSB after non-malignant finding on CNB was 21.6% (14% to DCIS and 7.6% to invasive cancer). Atypical ductal hyperplasia (ADH) was the most common pathology identified on CNB generating recommendation for DSB. The overall upgrade rate for ADH was 31%, including 5.5% to invasive cancer, and 25.5% to DCIS. Further analysis of these ADH upgrades to DCIS revealed majority to low grade DCIS. Discussion: A minority of patients with high-risk lesions, detected through screening mammography, were upgraded to malignancy on DSB in this cohort. The psychological and cost-effectiveness implications of this low upgrade rate to significant, life-threatening pathologies warrants further investigation. Future recommendations may involve including lesions of uncertain malignant potential or “high-risk” lesions in prospective observation and/or chemoprevention trials. This series suggests there may not be benefit in earlier diagnosis of the malignancies associated with ADH. Our data may therefore allow identification of groups of women who could be safely managed with less intensive treatment. Citation Format: Keane HJ, Elder K, Mann GB. Outcomes of diagnostic surgical biopsy in a population-based mammographic screening program [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-02-02.

Increasing trends in in situ breast cancer incidence in a region with no population-based mammographic screening program: results from Zurich, Switzerland 2003-2014.

Increase in in situ breast cancer (BCIS) incidence has been reported across Europe and the USA. However, little is known about the trends in BCIS incidence in regions without population-based mammographic screening programs. We set out to investigate these trends in Zurich, Switzerland, where only opportunistic mammographic screening exists. Data from 989 women diagnosed with a primary BCIS between 2003 and 2014 were used in our analyses. Age-standardized incidence rates per 100,000 person-years (ASR) were computed per year. Additional analyses by BCIS subtype, by age group at diagnosis and by incidence period were conducted. Incidence trends over time were assessed using joinpoint regression analysis. The overall BCIS ASR was 10.7 cases per 100,000 person-years with an increasing trend over the study period. A similar trend was observed for the ductal carcinoma in situ (DCIS) ASR, while the lobular carcinoma in situ (LCIS) ASR decreased. Age-specific analyses revealed that the 50-59year age group had the highest BCIS ASR. The highest increase in BCIS ASR, even though not statistically significant, was observed for the < 40year age group. BCIS ASR increased linearly over a 12-year period. The increase was reflected by an increase in DCIS ASR, whereas LCIS ASR decreased over time. The highest increase in BCIS ASR over the study period was observed for the < 40year age group, even though not statistically significant. Patient and tumor characteristics of this group that may be associated with BCIS development warrant further investigation.

Reasons for (non)participation in supplemental population-based MRI breast screening for women with extremely dense breasts

To determine the willingness of women with extremely dense breasts to undergo breast cancer screening with magnetic resonance imaging (MRI) in a research setting, and to examine reasons for women to participate or not. Between 2011 and 2015, 8,061 women (50-75 years) were invited for supplemental MRI as part of the Dense Tissue and Early Breast Neoplasm Screening (DENSE) trial (ClinicalTrials.gov Identifier: NCT01315015), after a negative screening mammography in the national population-based mammography screening programme. Demographics of participants and non-participants were compared. All invitees were asked to report reasons for (non)participation. Ethical approval was obtained. Participants provided written informed consent. Of the 8,061 invitees, 66% answered that they were interested, and 59% eventually participated. Participants were on average 54-years old (interquartile range: 51-59 years), comparable to women with extremely dense breasts in the population-based screening programme (55 years). Women with higher socio-economic status (SES) were more often interested in participation than women with lower SES (68% versus 59%, p<0.001). The most frequently stated reasons for non-participation were "MRI-related inconveniences and/or self-reported contraindications to MRI" (27%) and "anxiety regarding the result of supplemental screening" (21%). "Expected personal health benefit" (68%) and "contribution to science" (43%) were the most frequent reasons for participation. Of women invited for MRI because of extremely dense breasts, 59% participated. Common reasons for non-participation were "MRI-related inconveniences" and "anxiety regarding the result of supplemental screening". In case of future implementation, availability of precise evidence on benefits and harms might reduce this anxiety.

3.4-O7Informed choice in mammography screening program among migrant and non-migrant women: a survey among first-time invitees in Germany, 2013-2015

Background: In Germany, women aged 50 to 69 are invited biennially to the population-based mammography screening programme (MSP). There is still a broad discussion whether the benefits of the programme outweigh its harms. Hence, the concept of informed choice is of particular importance for MSP. The aim of this survey was to assess the proportion of informed choices among migrant and non-migrant women invited to the German MSP for the first time. Methods: A random sample of 17,349 women aged 50 from a sub-region of North Rhine Westphalia was invited to participate in a postal cross-sectional survey conducted in German and Turkish. Turkish and other migrants were identified by country of birth and German resettlers additionally by self-reported resettler-status. Turkish migrant women were oversampled, due to expected lower response-rates. The effect of migration status on informed choice and on its three components (knowledge, attitude and intention) were assessed by chi-square tests and logistic regression modelling. Results:5,847 (33.7%) women responded to the postal questionnaire. 4,113 complete cases were included in the analyses. The proportion of women making informed choices was low (27.1%). Turkish migrant women had the highest odds for making an uninformed choice (OR 5.30, 95%CI 1.92-14.66) independent of educational level. Other migrant groups only had slightly higher odds for making an uninformed choice (German resettlers: OR 1.50, 95%CI 1.00-2.25; other migrants: OR 1.57, 95%CI 0.96-2.57) compared to non-migrant women. Fewer Turkish and other immigrant women intended to participate in the MSP. Immigrant women had a more positive attitude and a lower proportion of sufficient knowledge compared to non-migrant women. Conclusions: The overall proportion of informed choice in the German MSP is low and knowledge is poor. Measures are needed to improve information materials, strengthen health literacy and create a user-friendly environment facilitating informed choices especially for migrant women.