Population-based Mammography Screening Research Articles

Abstract PO5-07-12: Feasibility of organized population-based mass-level mammography screening (0.2 million women) –Report from LMIC-Uzbekistan

Abstract Background. Breast cancer is one of the leading diseases worldwide. The early detection of breast cancer is the best way to improve survival. Mammography is included in the standard guidelines of all the leading organizations. The procedure is technically demanding and cost sensitive. Despite being a standard, it is not practical in many countries, and more so in LMIC. The state of Uzbekistan embarked on a massive, unique, organized population-based program of mass-level mammography screening, starting from one region of the country and expanding to others. Here, we report the process of such establishment and the feasibility of this innovative model. Methods. Realizing the importance of breast cancer screening, the Republic of Uzbekistan initiated a pilot project in the Bukhara Region. The area is divided into 12 districts. Every district was equipped with a stationary mammography machine in a regional polyclinic and one mobile van. The personnel were appropriately trained and a selection process was established to invite women for screening. The invitation was sent using the local area's existing municipality residential directory, which contains the complete demographic details of every individual living in the area. The state has 100 % coverage in the registry. The study targeted every woman aged 45-65 starting May 2021. All mammographs were digitally recorded and sent in real time to a centralized server at the National Republican Cancer Center in Tashkent, Uzbekistan. Reporting is performed at a centralized reading center on the information system platform. The program envisages a complete care pathway, from screening to diagnosis and treatment. Results. Over a period of two years, 140506 women in the age range–45-65 underwent mammography screening. Depending on the size of the target group of the district, an average of 30-60 mammograms were performed per day. A reported preliminary analysis shows the presence of BIRADS 0 in 4495, BIRADS 1 IN 78634, BIRADS 2 in 64345, BIRADS 4 in 4998, BIRADS 5 in 893. All women with BIRADS 4 and 5 were referred to the regional comprehensive cancer center for further evaluation. A total of 7570 patients underwent cytology and 408 underwent core biopsy. Depending on the reports, the patients were appropriately managed. A total of 1885 patients were recalled for additional screening owing to their inappropriate quality. After a year of function, the project was expanded with “Mobile Vans” to other regions of the country. An additional 13 mobile mammography vans were added after 1.5 years. From January 2023, approximately 50000 mammograms were additionally performed, taking the total number of screened women to 190506. Conclusion. Thus, it is feasible to plan and successfully implement state-owned mass-level mammography screenings. This project has the potential for duplication in any part of the world, and other organizations can learn from this extensive, wide program. Citation Format: Mirzagaleb Tillyashaykhov, Aysulu Seytmuratova, Alexander Ososkov, Saide Djanklich, Yakhyo Ziyaev, Dinesh Pendharlkar. Feasibility of organized population-based mass-level mammography screening (0.2 million women) –Report from LMIC-Uzbekistan [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-07-12.

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.

Rethinking screening mammography in Japan: next-generation breast cancer screening through breast awareness and supplemental ultrasonography.

Breast cancer mortality has not been reduced in Japan despite more than 20years of population-based screening mammography. Screening mammography might not be suitable for Japanese women who often have dense breasts, thus decreasing mammography sensitivity because of masking. The J-START study showed that breast ultrasonography increases the sensitivity and the detection rate for early invasive cancers and lowers the rate of interval cancers for Japanese women in their 40s. Breast awareness and breast cancer survival are directly correlated; however, breast awareness is not widely known in Japan. Next-generation breast cancer screening in Japan should consist of breast awareness campaigns for improving breast cancer literacy and supplemental breast ultrasonography to address the problem of false-negative mammograms attributable to dense breasts.

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.

Overcoming the limitations of screening mammography in Japan and Korea: a paradigm shift to personalized breast cancer screening based on ultrasonography.

Screening mammography programs have been implemented in numerous Western countries with the aim of reducing breast cancer mortality. However, despite over 20 years of population-based screening mammography, the mortality rates in Japan and Korea continue to rise. This may be due to the fact that screening mammography is not as effective for Japanese and Korean women, who often have dense breasts. This density decreases the sensitivity of mammography due to a masking effect. Therefore, the early detection of small invasive cancers requires more than just mammography, particularly for women in their 40s. This review discusses the limitations and challenges of screening mammography, as well as the keys to successful population-based breast cancer screening in Japan and Korea. This includes a focus on breast ultrasonography techniques, which are based on histopathologic anatomical knowledge, and personalized screening strategies that are based on risk assessments measured by glandular tissue components.

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.

Our experience using synthesized mammography vs full field digital mammography in population-based screening

BackgroundSynthesized Mammogram (SM) from Digital Breast Tomosynthesis (DBT) images is introduced to replace the routine Full Field Digital Mammography (FFDM) to reduce radiation dose. Purposeto compare the conspicuity of cancer related findings between SM and FFDM and combination of these methods with DBT MethodsThe study was conducted in a tertiary breast imaging center, where 200 women referred for screening were enrolled in the study sequentially. Patients underwent FFDM and DBT simultaneously and a two-year follow-up was done. Data was evaluated for Breast Imaging Reporting and Data System (BI-RADS) score, breast density, mass lesions, calcification, and focal asymmetry by two expert breast radiologists. Comparison between different methods was made by Cohen Kappa test. Results22 patients with likely malignant findings went under biopsy. Taking histopathologic findings and two-year follow up as reference, the overall sensitivity and specificity for FFDM+DBT (86.1 and 88.9 respectively) and SM+DBT (86.1 and 88.2) didn’t show a meaningful difference. Comparing SM and FFDM, calcification in 20 subjects were overlooked on SM, but later detected when combined with DBT. Considering breast composition and BI-RADS categorization, an excellent agreement existed between the readers. ConclusionScreening with SM+DBT shows comparable results with FFDM+DBT considering BI-RADS categorization of the patients. Although SM showed slightly inferior sensitivity compared to FFDM, after combining DBT with SM no malignant appearing calcification or mass lesion was missed.

Breast cancer risk predictions by birth cohort and ethnicity in a population-based screening mammography program.

To examine whether birth cohorts affect the risk of breast cancer for East Asian, First Nations, African, South Asian and Caucasian ethnicities in British Columbia (BC). We used Cox PH models adjusted for well-known risk factors, such as age, breast density, mammographic features on false positives, and family history, to examine risk of breast cancer among East Asian, First Nations, African and South Asian ethnicities, relative to Caucasian, across three birth cohorts. There were 813,280 participants and 11,166 in situ and invasive breast cancer diagnoses. East Asians screened in BC were found to have a lower risk of breast cancer in the birth cohort born pre-1946 compared to Caucasian, but there was no statistically significant decrease for East Asians born after 1946. First Nations had an increased risk of breast cancer compared with Caucasian for all birth cohorts ranging from 1.1 to 2.0x the risk, which was statistically significant for those born after 1965. South Asians showed a statistically significant decrease in risk ranging from 0.58 to 0.81x lower compared with Caucasians for all birth cohorts. Risk of breast cancer for South Asians living in BC was found to be lower than Caucasians for each birth cohort examined, while East Asians had a comparable risk of breast cancer, First Nations had a consistently higher risk than Caucasians. When accounting for birth cohort, compared to Caucasians, South Asians have a decreased risk, First Nations have an increased risk, and East Asians have a similar risk of breast cancer.

Isolated ductal carcinoma in situ in patients presenting to two breast units in Johannesburg

BACKGROUND: Ductal carcinoma in situ (DCIS) represents approximately 20% of all new breast cancers in countries with population-based mammography screening. South Africa is an upper middle-income country with no such screening programmes in place, and the proportion of isolated DCIS appears much lower than this. Most patients present with symptomatic disease and high-risk features. There are numerous controversies regarding the diagnosis and optimal management strategy for this premalignant condition, and the issue of overtreatment is much debated. Our study aimed to determine the proportion of patients presenting with isolated DCIS, to describe the clinical presentation and to describe the treatment provided. METHODS: This is a retrospective cohort study of patients with histologically confirmed isolated DCIS at Charlotte Maxeke Johannesburg Academic Hospital and Chris Hani Baragwanath Academic Hospital from July 2015 to March 2018. Records were collected from the existing clinical databases in both breast units and from the South African National Health Laboratory System. RESULTS: Out of 1 813 patients diagnosed and managed with breast malignancies in this period, 58 (3.1%) patients were identified with isolated DCIS. Forty-three (74.1%) of these patients were symptomatic. Thirty-four (58.6%) patients had a primary mastectomy, and 12 (20.6%) had breast-conserving surgery. CONCLUSION: The diagnosis of isolated DCIS is rare in our setting, and the majority of patients present with more advanced, symptomatic disease that is not deemed suitable for breast-conserving surgery. The short-term follow-up of our patients has shown a low rate of recurrence and mortality thus far. However, further long-term follow-up is needed.

Mammographic Breast Density, Benign Breast Disease, and Subsequent Breast Cancer Risk in 3.9 Million Korean Women.

Background Mammographic breast density and benign breast disease are strong risk factors for breast cancer. Accordingly, women with both risk factors may have a markedly high risk for developing breast cancer. Purpose To investigate the risk of breast cancer associated with the combination of mammographic density and benign breast disease in Korean women, where population-based mammographic breast cancer screening is provided for all women aged at least 40 years. Materials and Methods This is a retrospective analysis of data from a nationwide breast cancer screening program linked with the national cancer registry. The study included Korean women between 40-74 years of age screened for breast cancer between January 2009 and December 2010 and observed up to December 2020 (median follow-up of 10.6 years). Benign breast disease and breast density were extracted from mammography screening results. Cox proportional hazard regression analysis was used to calculate adjusted hazard ratios (HRs) for breast cancer risk. Results In this study, 3 911 348 women (mean age, 53 years ± 9 [SD]) were analyzed. During follow-up (median, 10.6 years), 58 321 women developed breast cancer. At screening, 10 729 (18.4%) cases of benign breast disease were detected among women who developed breast cancer. Women with extremely dense breasts (Breast Imaging Reporting and Data System [BI-RADS] density category D) and benign breast disease had a greater risk of breast cancer when compared with women presenting with fatty breast (BI-RADS density category A) and those without benign breast disease (HR, 2.75; 95% CI: 2.63, 2.88; P < .001). Women with benign breast disease and fatty breasts (HR, 1.49; 95% CI: 1.40, 1.58; P < .001) and women with extremely dense breasts and without benign breast disease (HR, 2.28; 95% CI: 2.20, 2.35; P < .001) also had an elevated breast cancer risk compared with women with fatty breast tissue. Conclusion Women with dense breasts and benign breast disease at screening mammography had an elevated risk of future breast cancer. © RSNA, 2022 Online supplemental material is available for this article.

The Fundamental Flaws of the CNBSS Trials: A Scientific Review.

Although the two Canadian National Breast Screening Study (CNBSS) trials were performed 40 years ago, their negative findings continue to heavily influence screening policies around the world. These policies, based on underestimates of the mortality reduction attributable to mammography particularly for women in the 40-49-year age range, contribute to increased mortality and morbidity from breast cancer. This review summarizes principles of a randomized controlled trial (RCT) and evaluates the compliance of the CNBSS1 and CNBSS2 RCTs in the context of these principles. We describe the fundamental flaws of the CNBSS trials, which failed to demonstrate mortality benefit of screening mammography and contribute to their being the only two outlier studies of eight screening mammography RCTs. The most significant flaws of the trials are (1) inadequate power to detect significant differences in breast cancer mortality; (2) very poor quality mammography with low sensitivity and cancer detection rates; (3) inclusion of women with symptoms of breast cancer; and (4) study design that allowed for violation of the randomization of the allocation process. Finally, we demonstrate that the conditions of the screening intervention in the CNBSS do not reflect the environment of modern population-based screening mammography programs.

Current status of breast cancer undetected by mammography in population-based breast cancer screening and associated factors

Objective This study aimed to promote the application of mammography (MMG) screening without performing a clinical breast examination (CBE). It examined population-based screening data, including history taking findings, to elucidate the status of breast cancer cases, detected solely by CBE, and to reveal the factors associated with breast cancer. Through this, it explored alternative methods for evaluating breast cancer cases, undetected by MMG, when CBE is omitted.Methods The linked anonymized data from women, who underwent breast cancer screening in 2014, 2016, or 2017, were prepared. The data were obtained from the Nishinomiya City database. Breast cancer, undetected by MMG, were defined as breast cancer cases diagnosed by close examination based on CBE only (MMG findings were category 2 or lower, with no abnormalities). To assess the quality of breast cancer screening, process indices were calculated for the overall population, and for patients indicated for close examination based on CBE but not MMG. The association of breast cancer with each factor was statistically analyzed (χ2 test, etc.).Results In total, 13,504 women underwent breast cancer screening. Close examination was required in 1,247 women (9.2%). Breast cancer was diagnosed in 44 women (3.5%), including four, who had breast cancer undetected by MMG. All of the process indices satisfied the acceptable values. Three of the four women with breast cancer, undetected by MMG, noticed a lump. Breast cancer was significantly associated with "subjective symptoms". The presence of a "lump" and "nipple discharge" were significantly more common in breast cancer patients.Conclusion Three of the four breast cancer cases, undetected by MMG screening, had a subjective symptom (lump). There was a significant association between subjective symptoms (lump and nipple discharge) and breast cancer. To avoid missing breast cancer, undetected by MMG alone, these symptoms should be especially evaluated in women to compensate for the omission of a CBE. This can be achieved by encouraging women experiencing symptoms to seek consult, performing a thorough history-taking and observation, engaging in multidisciplinary collaboration (communication from medical staff to physicians), and promoting breast awareness.

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.

National health system characteristics, breast cancer stage at diagnosis, and breast cancer mortality: a population-based analysis.

In some countries, breast cancer age-standardised mortality rates have decreased by 2-4% per year since the 1990s, but others have yet to achieve this outcome. In this study, we aimed to characterise the associations between national health system characteristics and breast cancer age-standardised mortality rate, and the degree of breast cancer downstaging correlating with national age-standardised mortality rate reductions. In this population-based study, national age-standardised mortality rate estimates for women aged 69 years or younger obtained from GLOBOCAN 2020 were correlated with a broad panel of standardised national health system data as reported in the WHO Cancer Country Profiles 2020. These health system characteristics include health expenditure, the Universal Health Coverage Service Coverage Index (UHC Index), dedicated funding for early detection programmes, breast cancer early detection guidelines, referral systems, cancer plans, number of dedicated public and private cancer centres per 10 000 patients with cancer, and pathology services. We tested for differences between continuous variables using the non-parametric Kruskal-Wallis test, and for categorical variables using the Pearson χ2 test. Simple and multiple linear regression analyses were fitted to identify associations between health system characteristics and age-standardised breast cancer mortality rates. Data on TNM stage at diagnosis were obtained from national or subnational cancer registries, supplemented by a literature review of PubMed from 2010 to 2020. Mortality trends from 1950 to 2016 were assessed using the WHO Cancer Mortality Database. The threshold for significance was set at a p value of 0·05 or less. 148 countries had complete health system data. The following variables were significantly higher in high-income countries than in low-income countries in unadjusted analyses: health expenditure (p=0·0002), UHC Index (p<0·0001), dedicated funding for early detection programmes (p=0·0020), breast cancer early detection guidelines (p<0·0001), breast cancer referral systems (p=0·0030), national cancer plans (p=0·014), cervical cancer early detection programmes (p=0·0010), number of dedicated public (p<0·0001) and private (p=0·027) cancer centres per 10 000 patients with cancer, and pathology services (p<0·0001). In adjusted multivariable regression analyses in 141 countries, two health system characteristics were significantly associated with lower age-standardised mortality rates: higher UHC Index levels (β=-0·12, 95% CI -0·16 to -0·08) and increasing numbers of public cancer centres (β=-0·23, -0·36 to -0·10). These findings indicate that each unit increase in the UHC Index was associated with a 0·12-unit decline in age-standardised mortality rates, and each additional public cancer centre per 10 000 patients with cancer was associated with a 0·23-unit decline in age-standardised mortality rate. Among 35 countries with available breast cancer TNM staging data, all 20 that achieved sustained mean reductions in age-standardised mortality rate of 2% or more per year for at least 3 consecutive years since 1990 had at least 60% of patients with invasive breast cancer presenting as stage I or II disease. Some countries achieved this reduction without most women having access to population-based mammographic screening. Countries with low breast cancer mortality rates are characterised by increased levels of coverage of essential health services and higher numbers of public cancer centres. Among countries achieving sustained mortality reductions, the majority of breast cancers are diagnosed at an early stage, reinforcing the value of clinical early diagnosis programmes for improving breast cancer outcomes. None.

Retrospective Analysis of Clinicopathological Features and Familial Cancer History of Synchronous Bilateral Breast Cancer.

Bilateral breast cancer is a strong predictor of BRCA 1/2 mutation and hence one criterion indicated for hereditary genetic testing. The purpose of this study is to assess the characteristics of synchronous bilateral breast cancer (SBBC) and its association with personal and familial cancer traits. Patients diagnosed with SBBC in our institute between 1992 and 2018 were retrospectively reviewed, and the information of clinicopathological features, personal and family cancer history were analyzed. Of the 307 SBBCs enrolled, the growing case number generally aligned with the regional breast cancer incidence after the era of population-based mammography screening. SBBC patients had similar cancer stages but worse survival outcomes than those in the standard scenario. A total of 42.0% had mixed pathological diagnoses, and 22.8% had discordant immunohistochemistry (IHC) subtypes from both sides, which contributed to treatment challenges. The correlation of SBBC with hereditary breast and ovarian cancer (HBOC) syndrome was strongly implied, as 20.7% of our SBBC patients with known familial cancer histories had HOBC-related familial cancers (breast, ovarian, or prostate cancers). These findings highlight the need for genetic counseling and germline mutation testing in patients with SBBC. Early PARP inhibitor treatment should also be considered in high-risk cases for outcome improvement.

Breast Density and Risk of Interval Cancers: The Effect of Annual Versus Biennial Screening Mammography Policies in Canada

Regular screening mammography reduces breast cancer mortality. However, in women with dense breasts, the performance of screening mammography is reduced, which is reflected in higher interval cancer rates (ICR). In Canada, population-based screening mammography programs generally screen women biennially; however, some provinces and territories offer annual mammography for women with dense breast tissue routinely and/or on recommendation of the radiologist. This study compared the ICRs in those breast screening programs with a policy of annual vs. those with biennial screening for women with dense breasts. Among 148,575 women with dense breasts screened between 2008 to 2010, there were 288 invasive interval breast cancers; screening programs with policies offering annual screening for women with dense breasts had fewer interval cancers 63/70,814 (ICR 0.89/1000, 95% CI: 0.67-1.11) compared with those with policies of usual biennial screening 225/77,761 (ICR 1.45 /1000 (annualized), 95% CI: 1.19-1.72) i.e. 63% higher (p = 0.0016). In screening programs where radiologists’ screening recommendations were able to be analyzed, a total of 76,103 women were screened, with 87 interval cancers; the ICR was lower for recommended annual (65/69,650, ICR 0.93/1000, 95% CI: 0.71, 1.16) versus recommended biennial screening (22/6,453, ICR 1.70/1000 (annualized), 95%CI: 0.70, 2.71)(p = 0.0605). Screening program policies of annual as compared with biennial screening in women with dense breasts had the greatest impact on reducing interval cancer rates. We review our results in the context of current dense breast notification in Canada.

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.