Quebec Breast Cancer Screening Program Research Articles

Association between radiologists' and facilities' characteristics and mammography screening detection of ductal carcinoma in situ.

The aim of our study was, first, to measure association between radiologists and facilities characteristics and DCIS detection. Second, to assess whether those characteristics affect differently the likelihood of detection of DCIS versus invasive breast cancer. When applicable, we examined whether the identified characteristics were similarly associated with low-grade and high-grade DCIS detection. This retrospective cohort study included 1,750,002 digital screening mammograms (2145 screen-detected DCIS) performed in the Quebec breast cancer screening program between 2007 and 2015 inclusively. The associations between radiologists' and facilities' characteristics and (1) the DCIS detection rate, (2) the invasive detection rate, and (3) the odds of DCIS on invasive detection were assess. For statistically significant associations in the latter analysis, analyses stratified by DCIS grade were performed. Multivariable logistic regression with generalized estimating equations estimates to account for correlation among mammograms was used. Compared to radiologists with recall rate between 5.0 and 9.9%, radiologists with recall rate between 15.0-19.9% and ≥ 20% reached a higher DCIS detection rate, with adjusted detection ratios of, respectively, 1.33 (95% confidence interval = 1.15-1.53) and 1.43 (95% confidence interval = 1.13-1.81). Increase in radiologist' recall rate was statistically significantly associated with an increase in detection of low/intermediate-grade DCIS (P < 0.001), while not in high-grade DCIS (P = 0.15). A major determinant of DCIS detection is the radiologists' recall rate. Abnormalities referred by radiologists with higher recall rates should be identified in order to understand how to decrease recall rate while keeping an optimal DCIS and invasive detection rate.

Social inequalities in breast cancer screening: evaluating written communications with immigrant Haitian women in Montreal

BackgroundThe province of Quebec (Canada) has implemented a breast cancer screening program to diagnose this cancer at an early stage. The strategy is to refer women 50 to 69 years old for a mammogram every two years by sending an invitation letter that acts as a prescription. Ninety per cent (90%) of deaths due to breast cancer occur in women aged 50 and over. Numerous studies have shown social inequalities in health for most diseases. With breast cancer, a significant paradox arises: its incidence is lower among disadvantaged women and yet, more of them die from this disease. The health care system might play a role in this inequality. The scientific literature documents the potential for creating such inequalities when prevention does not consider equity among social groups. Immigrant women are often disadvantaged. They die of breast cancer more than non-immigrants. Studies attribute this to late-stage diagnosis due to poor adherence to mammography screening programs.Purpose of the studyThe main objective of our research is to assess how Haitian immigrant women in Montreal are reached by the Quebec Breast Cancer Screening Program, and specifically how they perceive the mammogram referral letter sent by the program.MethodsThe study uses a two-step qualitative method: i) In-depth interviews with influential community workers to identify the most relevant issues; ii) Focus groups with disadvantaged women from Montreal’s Haitian community.ResultsA mammogram referral letter from the Breast Cancer Screening Program may be a barrier to compliance with mammography by underprivileged Haitian women in Montreal. This might be attributable to a low level of literacy, poor knowledge of the disease, and lack of financial resources.ConclusionBarriers may be underestimated in underprivileged immigrant and non-immigrant communities. A preventive strategy must be adapted to different sub-groups and must also take into account lower literacy levels. To increase mammography uptake, it is crucial that the benefits of prevention be clearly identified and described in understandable terms. Finally, economic access to follow-up measures should be considered.

Incorporating patient preferences in the design and operation of cancer screening facility networks

High participation by target populations is one of the key success factors of publicly funded and population-based cancer screening programs. Patient preferences are a major factor distinguishing preventive screening from treatment, specifically regarding participation and choice of facility. Here, we explore the effect of facility attributes on patients’ choices for cancer screening and propose a quantitative modeling framework to study the impact of various system- and facility-level interventions by incorporating the choice behaviors of heterogeneous patient populations. EPPM integrates an empirical study on patient preferences and a simulation-based optimization model that incorporates the preferences of multiple patient types into an M/G/s queuing network of facilities, each working with appointment. Based on our framework's application via an extensive case study on the Quebec Breast Cancer Screening Program in Montreal, we provide insights into improving participation in cancer screening networks. Specifically, we identify trade-offs that women make when choosing facilities with different attribute configurations and show the heterogeneity in patient preferences. We also find that facility-level interventions, such as providing free parking and improving staff manners, are more effective and less expensive than system-level interventions.

Screening Sensitivity According to Breast Cancer Location

PurposeTo examine the relation between breast cancer location and screening mammogram sensitivity, and assess whether this association is modified by body mass index (BMI) or breast density. MethodsThis study is based on all interval cancers (n = 481) and a random sample of screen-detected cancers (n = 481) diagnosed in Quebec Breast Cancer Screening Program participants in 2007. Film-screening mammograms, diagnostic mammograms, and ultrasound reports (when available) were requested for these cases. The breast cancer was then localised in mediolateral oblique (MLO) and craniocaudal (CC) projections of the breast by 1 experienced radiologist. The association between cancer location and screening sensitivity was assessed by logistic regression. Adjusted sensitivity and sensitivity ratios were obtained by marginal standardisation. ResultsA total of 369 screen-detected and 268 interval cancers could be localised in MLO and/or CC projections. The 2-year sensitivity reached 68%. Overall, sensitivity was not statistically associated with location of the cancer. However, sensitivity seems lower in MLO posterior inferior area for women with BMI ≥ 25 kg/m2 compared to sensitivity in central area for women with lower BMI (adjusted sensitivity ratio: 0.58, 95% confidence interval [CI]: 0.17–0.98). Lower sensitivity was also observed in subareolar areas for women with breast density ≥ 50% compared to the central areas for women with lower breast density (for MLO and CC projections, adjusted sensitivity ratio and 95% CI of, respectively, 0.54 [0.13–0.96] and 0.46 [0.01–0.93]). ConclusionsScreening sensitivity seems lower in MLO posterior inferior area in women with higher BMI and in subareolar areas in women with higher breast density. When interpreting screening mammograms, radiologists need to pay special attention to these areas.

QIM19-119: Validity of the French-Language Mammography Satisfaction Instrument Evaluating Women’s Satisfaction With an Organized Breast Cancer Screening Program: A Confirmatory Study

Background: To evaluate the quality of an organized mammography screening program based on the perception of screened women, we developed and validated the French-language Mammography Satisfaction Instrument (MSI). The study objective was to confirm the validity and reliability of the MSI. Methods: A confirmatory study was conducted among 529 women who had had a recent screening mammography under the Quebec Breast Cancer Screening Program (PQDCS). Eligible women from the Quebec City region completed the online MSI between January 14 and May 23, 2016. The MSI originally included 14 items evaluating 4 factors: satisfaction with (1) the technician’s skills; (2) the physical environment; (3) the staff’s communication skills; and (4) the information provided under the program. A fifth factor with 2 items, evaluating mammography accessibility, was added. A confirmatory factor analysis (CFA) was done and goodness of fit indices were generated (SRMR, CFI, RMSEA with its 90% CI). Item reliability and composite reliability were estimated. Variance extract estimates (VEEs) were generated to assess the amount of variance explained by the factors. Multivariate logistic regressions were done to test the sensitivity of each scale to identify subgroups of unsatisfied women. Odds ratios (OR) and their 95% CI were estimated. Results: Most women (62.0%) were aged 55–64, and 32.9% had university level education. The CFA demonstrated that the 5 factors fitted the data well (SRMR=0.044; CFI=0.969; RMSEA=0.055 with its 90% CI: 0.047–0.063). Item reliabilities (≥0.55) and composite reliabilities (≥0.87) were high. All VEEs were also high (≥0.70). Pain during compression, anxiety before the mammography, perception of not having an excellent health, and the radiologic centers were the factors the most consistently and significantly associated with the 5 scales of satisfaction. In addition, women with university level education were less satisfied with the staff’s communication skills (OR=0.64; 95% CI: 0.43–0.97) and those having had less than 10 lifetime mammograms were less satisfied with the physical environment (OR=0.52; 95% CI: 0.33–0.83) and the accessibility (OR=0.53; 95% CI: 0.31–0.92). Conclusions: This confirmatory study showed the good reliability and validity of the construct of the 16-item MSI with 5 factors. The MSI is useful to detect unsatisfied women and to improve the quality of organized breast cancer screening programs.

Mammography Clinical Image Quality and the False Positive Rate in a Canadian Breast Cancer Screening Program

PurposeThe study sought to determine if mammography quality is associated with the false positive (FP) rate in the Quebec breast cancer screening program in 2004 and 2005. MethodsMammography quality of a random sample of screen-film mammograms was evaluated by an expert radiologist following the criteria of the Canadian Association of Radiologists. For each screening examination, scores ranging from 1 (poor quality) to 5 (excellent quality) were attributed for positioning, compression, contrast, exposure level, sharpness, and artifacts. A final overall quality score (lower or higher) was also given. Poisson regression models with robust estimation of variance and adjusted for potential confounding factors were used to assess associations of mammography quality with the FP rate. ResultsAmong 1,209 women without cancer, there were 104 (8.6%) FPs. Lower overall mammography quality is associated with an increase in the FP rate (risk ratio [RR], 1.4; 95% confidence interval [CI], 1.0-2.1; P = .07) but this increase was not statistically significant. Artifacts were associated with an increase in the FP rate (RR, 2.1; 95% CI, 1.3-3.3; P = .01) whereas lower quality of exposure level was related to a reduction of the FP rate (RR, 0.4; 95% CI, 0.1-1.0; P = .01). Lower quality scores for all other quality attributes were related to a nonstatistically significant increase in the FP rate of 10%-30%. ConclusionsArtifacts can have a substantial effect on the FP rate. The effect of overall mammography quality on the FP rate may also be substantial and needs to be clarified.

Clinical Image Quality and Sensitivity in an Organized Mammography Screening Program

PurposeThe study sought to examine the association between clinical image quality of mammograms and screening sensitivity. MethodsFour radiologists evaluated the clinical image quality of 374 invasive screen-detected cancers and 356 invasive interval breast cancers for which quality evaluation of screening mammograms could be assessed from cancers diagnosed among participants in the Quebec Breast Cancer Screening Program in 2007. Quality evaluation was based on the Canadian Association of Radiologists accreditation criteria, which are similar to those of the American College of Radiology. The association between clinical quality and screening sensitivity was assessed by logistic regression. Adjusted sensitivity and adjusted sensitivity ratios were obtained through marginal standardization. No institutional review board approval was required. ResultsA proportion of 28% (206 of 730) of screening mammograms had lower overall quality for the majority of assessments. Positioning was the quality attribute that was the most frequently deficient. The 2-year screening sensitivity reached 68%. Sensitivity of screening was not statistically associated with the overall quality (ratio of 2-year sensitivity = 1.03; 95% confidence interval: 0.93-1.15) or with any quality attributes (positioning, exposure, compression, sharpness, artifacts, contrast). Results were similar for the 1-year sensitivity. ConclusionsAlthough not all mammograms in the Quebec screening program met the optimum quality required by the Canadian Association of Radiologists or American College of Radiology accreditation, the screening mammograms produced in this population-based organized screening program reached a high enough level of quality so that the remaining variation in quality is too little to impair screening sensitivity.

Frequency and Determinants of a Short-Interval Follow-up Recommendation After an Abnormal Screening Mammogram

PurposeAfter imaging assessment of an abnormal screening mammogram, a follow-up examination 6 months later is recommended to some women. Our aim was to identify which characteristics of lesions, women, and physicians are associated to such short-interval follow-up recommendation in the Quebec Breast Cancer Screening Program. MethodsBetween 1998 and 2008, 1,839,396 screening mammograms were performed and a total of 114,781 abnormal screens were assessed by imaging only. Multivariate analysis was done with multilevel Poisson regression models with robust variance and generalized linear mixed models. ResultsA short-interval follow-up was recommended in 26.7% of assessments with imaging only, representing 2.3% of all screens. Case-mix adjusted proportion of short-interval follow-up recommendations varied substantially across physicians (range: 4%-64%). Radiologists with high recall rates (≥15%) had a high proportion of short-interval follow-up recommendation (risk ratio: 1.82; 95% confidence interval: 1.35-2.45) compared to radiologists with low recall rates (<5%). The adjusted proportion of short-interval follow-up was high (22.8%) even when a previous mammogram was usually available. ConclusionsShort-interval follow-up recommendation at assessment is frequent in this Canadian screening program, even when a previous mammogram is available. Characteristics related to radiologists appear to be key determinants of short-interval follow-up recommendation, rather than characteristics of lesions or patient mix. Given that it can cause anxiety to women and adds pressure on the health system, it appears important to record and report short-interval follow-up and to identify ways to reduce its frequency. Short-interval follow-up recommendations should be considered when assessing the burden of mammography screening.

Clinical Image Quality in Daily Practice of Breast Cancer Mammography Screening

ObjectiveTo assess the quality of screening mammograms performed in daily practice in the Quebec Breast Cancer Screening Program. Subjects and MethodsClinical image quality of a random subsample of 197 screening mammograms performed in 2004-2005 was independently evaluated by 2 radiologists based on the criteria by Canadian Association of Radiologists (CAR). When disagreement occurred for overall judgement or positioning score, the mammograms were reviewed by a third radiologist. Cohen's kappas for interrater agreement were computed. Multivariable robust Poisson regression models were used to study associations of overall quality and positioning with body mass index (BMI) and breast density. ResultsThe CAR criteria were not satisfied for 49.7% of the mammograms. Positioning was the quality attribute most often deficient, with 37.2% of mammograms failing positioning. Interrater agreement ranged from slight (kappa = 0.02 for compression and sharpness) to fair (kappa = 0.30 for exposure). For overall quality, women with a BMI ≥ 30 kg/m2 had a failure proportion of 67.5% compared with 34.9% for women with a BMI<25 kg/m2 (risk ratio 2.1 [95% confidence interval, 1.5-3.0]). For positioning, women with a BMI ≥ 30 kg/m2 had a failure proportion of 53.8% compared with 27.9% for women with a BMI < 25 kg/m2 (risk ratio 1.9 [95% confidence interval, 1.2-3.1]). Effects of breast density on image quality differed among radiologists. ConclusionDespite measures to ensure high-quality imaging, including CAR accreditation, approximately half of this random sample of screening mammograms failed the CAR quality standards. It would be important to define quality targets for screening mammograms carried out in daily practice to interpret such observations.

Radiologist Interpretive Volume and Breast Cancer Screening Accuracy in a Canadian Organized Screening Program

To strengthen evidence on which radiologist mammography interpretive volume requirements can be based, we assessed the relation of volume to accuracy in the Quebec Breast Cancer Screening Program. Annual interpretive volume (total, screening, and diagnostic) for all 340 radiologists who interpreted 1315327 screening examinations in the period from 2000 to 2006 was obtained using provincial databases. The association of volume to sensitivity, false-positive rate, and accuracy (sensitivity/false-positive rate) was assessed by multivariable Poisson regression with robust error variance. All statistical tests were two-sided. Radiologists consistently interpreting less than 500 mammograms annually experienced a 58% reduction in accuracy (adjusted accuracy ratio = 0.42; 95% confidence interval [CI] = 0.24 to 0.74) compared with those who consistently interpreted at least 500 mammograms annually. Moreover, accuracy increased progressively as total annual volume increased (P trend = .0005). Radiologists interpreting at least 4000 mammograms annually experienced a 32% increase in accuracy (adjusted accuracy ratio = 1.32; 95% CI = 1.13 to 1.54) compared with those interpreting 500 to 999 mammograms annually. This increase in accuracy is attributable to a reduction in false-positive rate as total volume increased (P trend = .001). Sensitivity changed little with total volume (P trend = .68). Gains in accuracy were greater up to approximately 3000 mammograms interpreted annually. The minimum annual volume of 500 mammograms required in North America is justified; radiologist accuracy may be compromised if interpretive volume is consistently less than this requirement. Raising interpretive volume may help to reduce the frequency of false positives without loss of sensitivity. Possible gains in accuracy may be greater with increases in volume of up to approximately 3000 mammograms interpreted annually.

Nurses' Intention to Support Informed Decision-Making about Breast Cancer Screening with Mammography: A Survey

There is growing interest in informed decision-making about breast cancer screening with mammography and growing advocacy for the provision of balanced information about potential benefits and harms. The authors report on a survey evaluating nurses' intention to support women targeted by the Quebec Breast Cancer Screening Program in making informed decisions about breast cancer screening with mammography. Of the 840 questionnaires completed, 618 were included in the data analysis. The mean +/- standard deviation score for intention was 1.7 +/- 1.2 on a 6-point Likert scale ranging from -3 to +3, indicating strong intention to support the targeted women. Perceived behavioural control was the theory-based variable most strongly associated with intention, followed by attitude and social norm. These results can be used to develop interventions to train nurses in integrating informed decision-making about breast cancer screening with mammography into their practice and to design relevant decision support tools.

Access to Breast Cancer Screening Programs for Women with Disabilities

The goal of this study was to identify measures to facilitate access to the Quebec Breast Cancer Screening Program for women with activity limitations, considering the barriers to screening uptake in that population. The study was carried out in three stages. First, 124 semi-structured interviews were conducted in five regions of Quebec with five groups of key informants. The content analysis lead to the identification of 64 proposals, which were submitted to 31 experts through a two-round Delphi survey process. Finally, consultations were held with 11 resource people to determine which decision-making levels (local, regional, provincial) could play a key role in implementing the proposals. A strong consensus (≥80%) was achieved for 25 proposals seen as highly relevant and feasible. The implementation of such proposals could substantially improve access to screening, given the prevalence of activity limitations in the age group targeted by the program.

517: Post-Normal Screen Breast Cancer in the Quebec Breast Cancer Screening Program (PQDCS)

517: Post-Normal Screen Breast Cancer in the Quebec Breast Cancer Screening Program (PQDCS)

Volume of screening mammography and performance in the Quebec population-based Breast Cancer Screening Program

In the Quebec Breast Cancer Screening Program (Programme quebecois de depistage du cancer du sein [PQDCS]), radiologists' and facilities' volumes of screening mammography vary considerably. We examined the relation of screening-mammography volume to rates of breast cancer detection and false-positive readings in the PQDCS. The study population included 307,314 asymptomatic women aged 50-69 years screened during 1998-2000. Breast cancer detection rates were analyzed by comparing all women with screening-detected breast cancer (n = 1709) and a 10% random sample of those without (n = 30,560). False-positive rates were analyzed by comparing the 3159 women with false-positive readings and the 27,401 others in the 10% random sample. Characteristics of participants, radiologists and facilities were obtained from the PQDCS information system. Data were analyzed by means of logistic regression. The rate of breast cancer detection appeared to be unrelated to the radiologist's screening-mammography volume but increased with the facility's screening-mammography volume. The breast cancer detection rate ratio for facilities performing 4000 or more screenings per year, compared with those performing fewer than 2000, was 1.28 (95% confidence interval [CI] 1.07-1.52). In contrast, the frequency of false-positive readings was unrelated to the facility's screening volume but was inversely related to the radiologist's screening volume: the rate ratio for readers of 1500 or more screenings per year compared with those reading fewer than 250 was 0.53 (95% CI 0.35-0.79). Radiologists' and facilities' caseloads showed independent and complementary associations with performance of screening mammography in the PQDCS. Radiologists who worked in larger facilities and read more screening mammograms had higher breast cancer detection rates while maintaining lower false-positive rates.