Quality of palliative and end-of-life care: a quantitative study of temporal trends and differences according to illness trajectories in Quebec (Canada).

BACKGROUND: Our aim was to assess temporal trends and compare quality indicators related to Palliative and End-of-Life Care (PEoLC) experienced by people dying of cancer (trajectory I), organ-failure (Trajectory II), and frailty/dementia (trajectory III) in Quebec (Canada) between 2002 and 2016. METHODS: This descriptive population-based study focused on the last month of life of decedents who, based on the principal cause of death, would have been likely to benefit from palliative care. Five PEoLC indicators were assessed: home deaths (1), deaths in acute care beds with no PEoLC services (2), at least one Emergency Room (ER) visit in the last 14 days of life (3), ER visits on the day of death (4) and at least one Intensive Care Unit (ICU) admission in the last month of life (5). Data were obtained from Quebec's Integrated Chronic Disease Surveillance System (QICDSS). RESULTS: The annual percentage of home deaths increased slightly between 2002 and 2016 in Quebec, rising from 7.7 to 9.1%, while the percentage of death during a hospitalization in acute care without palliative care decreased from 39.6% in 2002 to 21.4% in 2016. Patients with organ failure were more likely to visit the ER on the day of death (20.9%) than patients dying of cancer and dementia/frailty with percentages of 12.0% and 6.4% respectively. Similar discrepancies were observed for ICU visits in the last month and ER visits in the last 14 days. CONCLUSION: PEoLC indicators showed more aggressiveness of care for patients with organ failure and highlight the need for more equitable access to quality PEoLC between malignant and non-malignant illness trajectories. These results underline the challenges of providing timely and optimal PEoLC.

A phase IIb randomized placebo-controlled trial testing the effect of MAG-EPA long-chain omega-3 fatty acid dietary supplement on prostate cancer proliferation.

BACKGROUND: High prostate eicosapentaenoic fatty acid (EPA) levels were associated with a significant reduction of upgrading to grade group (GG) ≥ 2 prostate cancer in men under active surveillance. We aimed to evaluate the effect of MAG-EPA long-chain omega-3 fatty acid dietary supplement on prostate cancer proliferation. METHODS: A phase II double-blind randomized placebo-controlled trial was conducted in 130 men diagnosed with GG ≥ 2 prostate cancer and undergoing radical prostatectomy between 2015-2017 (Clinicaltrials.gov: NCT02333435). Participants were randomized to receive 3 g daily of either MAG-EPA (n = 65) or placebo (n = 65) for 7 weeks (range 4-10) prior to radical prostatectomy. The primary outcome was the cancer proliferation index quantified by automated image analysis of tumor nuclear Ki-67 expression using standardized prostatectomy tissue microarrays. Additional planned outcomes at surgery are reported including plasma levels of 27 inflammatory cytokines and fatty acid profiles in circulating red blood cells membranes and prostate tissue. RESULTS: Cancer proliferation index measured by Ki-67 expression was not statistically different between the intervention (3.10%) and placebo (2.85%) groups (p = 0.64). In the per protocol analyses, the adjusted estimated effect of MAG-EPA was greater but remained non-significant. Secondary outcome was the changes in plasma levels of 27 cytokines, of which only IL-7 was higher in MAG-EPA group compared to placebo (p = 0.026). Men randomized to MAG-EPA prior to surgery had four-fold higher EPA levels in prostate tissue compared to those on placebo. CONCLUSIONS: This MAG-EPA intervention did not affect the primary outcome of prostate cancer proliferation according to nuclear Ki-67 expression. More studies are needed to decipher the effects of long-chain omega-3 fatty acid dietary supplementation in men with prostate cancer.

It is thought that our diet can impact our risk of cancer and affect outcomes in patients with cancer. Omega-3 fatty acids, mostly found in fatty fish, might be beneficial by protecting against prostate cancer and its adverse outcomes. We conducted a clinical trial to test the effects of an omega-3 dietary supplement (MAG-EPA) in men with prostate cancer. We randomly allocated 130 men to receive either MAG-EPA or a placebo for 7 weeks before their prostate cancer surgery. We measured a marker of how much tumor cells were proliferating (or growing in number) at the point of surgery, which might indicate how aggressive their disease was. However, the supplement did not affect tumor cell proliferation. The supplement was therefore not beneficial in this group of patients and further studies  are needed to test and confirm the effects of MAG-EPA on prostate cancer cells.

Using Real-World Data to Determine Health System Costs of Ontario Women Screened for Breast Cancer.

Our study was to determine breast cancer screening costs in Ontario, Canada for screenings conducted through a formal (Ontario Breast Screening Program, OBSP) and informal (non-OBSP) screening program using administrative databases. Included women were 49-74 years of age when receiving screening mammograms between 1 January 2013 to 31 December 2019. Each woman was followed for a screening episode with screening and diagnostic components, and costs were calculated as an average cost per woman per month in 2021 Canadian dollars. The final cohort of 1,546,386 women screened had a mean age of 59.4 ± 7.1 years and ~87% were screened via OBSP. The average total cost per woman per month was $136 ± $103, $134 ± $103 and $155 ± $104 for the entire, OBSP and non-OBSP cohorts, respectively. This was further disaggregated into the average total screening cost per month, which was $103 ± $8, $100 ± $4 and $117 ± $9 per woman, and the average total diagnostic cost per woman per month at $219 ± $166, $228 ± $165 and $178 ± $159. for the entire, OBSP and non-OBSP cohorts, respectively. These results indicate similar screening costs across the different cohorts, but higher diagnostic costs for the OBSP cohort.

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

PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Omega-3 Fatty Acids Survey in Men under Active Surveillance for Prostate Cancer: from Intake to Prostate Tissue Level.

Dietary omega-3 fatty acids (ω3), particularly long-chain ω3 (LCω3), have protective effects against prostate cancer (PCa) in experimental studies. Observational studies are conflicting, possibly because of the biomarker used. This study aimed at evaluating associations between grade reclassification and ω3 levels assessed in prostatic tissue, red blood cells (RBC), and diet. We conducted a validation cross-sectional study nested within a phase II clinical trial. We identified 157 men diagnosed with low-risk PCa who underwent a first active surveillance repeat prostate biopsy session. Fatty acid (FA) intake was assessed using a food frequency questionnaire and their levels measured in prostate tissue and RBC. Associations were evaluated using logistic regression. At first repeat biopsy session, 39 (25%) men had high-grade PCa (grade group ≥2). We found that high LCω3-eicosapentaenoic acid (EPA) level in prostate tissue (odds ratio (OR) 0.25; 95% (confidence interval (CI) 0.08-0.79; p-trend = 0.03) was associated with lower odds of high-grade PCa. Similar results were observed for LCω3 dietary intake (OR 0.30; 95% CI 0.11-0.83; p-trend = 0.02) but no association for RBC. LCω3-EPA levels in the target prostate tissue are inversely associated with high-grade PCa in men with low-risk PCa, supporting that prostate tissue FA, but not RBC FA, is a reliable biomarker of PCa risk.

Screening Sensitivity According to Breast Cancer Location.

PURPOSE: To 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. METHODS: This 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. RESULTS: A 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]). CONCLUSIONS: Screening 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.

The mammography screening detection of ductal carcinoma in situ and invasive breast cancer according to women's characteristics: is it the same?

PURPOSE: Detection of ductal carcinoma in situ (DCIS) has increased with the mammography dissemination. Given the potential role of DCIS as a precursor of invasive breast cancer (IBC), we aimed to assess whether women's characteristics have a different effect on the DCIS compared to IBC detection rate. METHODS: This study included 3,609,569 screening mammograms performed from 2002 to 2015 in our organized breast cancer screening program, which actively invites women 50-69 years of age. The association between women's characteristics and the DCIS detection rate, the IBC detection rate and the odds ratio of DCIS among screen-detected cancers was assessed by logistic regression and generalized estimating equations with independent correlation matrix and sandwich estimator. RESULTS: A total of 4173 DCIS and 15,136 IBC were screen-detected. Increasing women's age, current hormone replacement therapy use and higher body mass index were less associated with the DCIS than with IBC detection rates (p value for the odds of DCIS among screen-detected cancers of, respectively, < 0.0001, 0.0244 and < 0.0001). In contrast, having a previous breast aspiration or biopsy and increasing breast density were more strongly associated with DCIS than with IBC detection rates (p value of, respectively, 0.0050 and < 0.0001). CONCLUSION: The results suggest that some women's characteristics could be playing a role in the initiation and other in the progression from in situ to invasive breast cancer. These characteristics can also affect the screening sensitivity, and this effect may differ depending on whether screen-detected cases were DCIS or IBC.

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

PURPOSE: The 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. METHODS: Mammography 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. RESULTS: Among 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%. CONCLUSIONS: Artifacts 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.

PURPOSE: The study sought to examine the association between clinical image quality of mammograms and screening sensitivity. METHODS: Four 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. RESULTS: A 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. CONCLUSIONS: Although 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.

Effects of concentrated long-chain omega-3 polyunsaturated fatty acid supplementation before radical prostatectomy on prostate cancer proliferation, inflammation, and quality of life: study protocol for a phase IIb, randomized, double-blind, placebo-controlled trial.

BACKGROUND: Prostate cancer is the most commonly diagnosed cancer in north-American men. Few dietary or lifestyle interventions have been tested to prevent prostate cancer progression. Omega-3 fatty acid supplementation represents a promising intervention for prostate cancer patients. The aim of the study is to evaluate the effects of long-chain omega-3 polyunsaturated fatty acids (LCn3), more precisely eicosapentaenoic acid monoacylglyceride (MAG-EPA) supplementation, on prostate cancer proliferation, inflammation mediators and quality of life among men who will undergo radical prostatectomy. METHODS/DESIGN: We propose a phase IIb, randomized, double-blind placebo-controlled trial of MAG-EPA supplementation for 130 men who will undergo radical prostatectomy as treatment for a prostate cancer of Gleason score ≥ 7 in an academic cancer center in Quebec City. Participants will be randomized to 6 capsules of 625 mg of fish oil (MAG-EPA) per capsule containing 500 mg of EPA daily or to identically looking capsules of high oleic acid sunflower oil (HOSO) as placebo. The intervention begins 4 to 10 weeks prior to radical prostatectomy (baseline) and continues for one year after surgery. The primary endpoint is the proliferative index (Ki-67) measured in prostate cancer cells at radical prostatectomy. A secondary endpoint includes prostate tissue levels of inflammatory mediators (cytokines and proteins) at time of radical prostatectomy. Changes in blood levels of inflammatory mediators, relative to baseline levels, at time of radical prostatectomy and 12 months after radical prostatectomy will also be evaluated. Secondary endpoints also include important aspects of psychosocial functioning and quality of life such as depression, anxiety, sleep disturbances, fatigue, cognitive complaints and prostate cancer-specific quality of life domains. The changes in these outcomes, relative to baseline levels, will be evaluated at 3, 6, 9 and 12 months after radical prostatectomy. DISCUSSION: The results from this trial will provide crucial information to clarify the role of omega-3 supplementation on prostate cancer proliferation, inflammation and quality of life. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02333435. Registered on December 17, 2014. Last updated September 6, 2016.

Mathematical Modeling of the Transmission Dynamics of Clostridium difficile Infection and Colonization in Healthcare Settings: A Systematic Review.

BACKGROUND: We conducted a systematic review of mathematical models of transmission dynamic of Clostridium difficile infection (CDI) in healthcare settings, to provide an overview of existing models and their assessment of different CDI control strategies. METHODS: We searched MEDLINE, EMBASE and Web of Science up to February 3, 2016 for transmission-dynamic models of Clostridium difficile in healthcare settings. The models were compared based on their natural history representation of Clostridium difficile, which could include health states (S-E-A-I-R-D: Susceptible-Exposed-Asymptomatic-Infectious-Resistant-Deceased) and the possibility to include healthcare workers and visitors (vectors of transmission). Effectiveness of interventions was compared using the relative reduction (compared to no intervention or current practice) in outcomes such as incidence of colonization, CDI, CDI recurrence, CDI mortality, and length of stay. RESULTS: Nine studies describing six different models met the inclusion criteria. Over time, the models have generally increased in complexity in terms of natural history and transmission dynamics and number/complexity of interventions/bundles of interventions examined. The models were categorized into four groups with respect to their natural history representation: S-A-I-R, S-E-A-I, S-A-I, and S-E-A-I-R-D. Seven studies examined the impact of CDI control strategies. Interventions aimed at controlling the transmission, lowering CDI vulnerability and reducing the risk of recurrence/mortality were predicted to reduce CDI incidence by 3-49%, 5-43% and 5-29%, respectively. Bundles of interventions were predicted to reduce CDI incidence by 14-84%. CONCLUSIONS: Although CDI is a major public health problem, there are very few published transmission-dynamic models of Clostridium difficile. Published models vary substantially in the interventions examined, the outcome measures used and the representation of the natural history of Clostridium difficile, which make it difficult to synthesize results and provide a clear picture of optimal intervention strategies. Future modeling efforts should pay specific attention to calibration, structural uncertainties, and transparent reporting practices.

Technologists' Characteristics and Quality of Positioning in Daily Practice in a Canadian Breast Cancer Screening Program.

RATIONALE AND OBJECTIVES: This study evaluates to what extent technologists' experience, training, or practice in mammography are associated with screening mammography positioning quality. MATERIALS AND METHODS: Positioning quality of a random sample of 1278 mammograms drawn from the 394,190 screening examinations performed in 2004-2005 in the Breast Cancer Screening Program of Quebec (Canada) was evaluated by an expert radiologist. Information on technologists' experience, training, and practice was obtained by mailed questionnaire. Multivariable Poisson regression models with robust estimation of variance were used to assess the association of technologists' characteristics with higher positioning quality. RESULTS: Of 254 randomly selected technologists, 220 (86.6%) completed the questionnaire. Participating technologists did 89.2% of available sampled mammograms (1088 of 1220), of which 45.9% were of higher positioning quality. Technologists who, in addition to mandatory training, followed at least 15 hours of hands-on training in positioning performed higher positioning quality (adjusted ratio = 1.3, 95%CI = 1.1-1.5) than technologists with no such additional training. Technologists providing at least 15 hours of continued medical education also performed higher positioning quality (adjusted ratio = 1.3, 95%CI = 1.1-1.5) than those who provided less than 15 hours of continued medical education. Being involved in film development and proportion of mammograms performed that are screening compared to diagnostic were also associated with positioning quality, although the latter association was less clear. CONCLUSIONS: Extra hands-on training in positioning could further improve screening mammography positioning quality in the screening program because many technologists did not have such additional training.

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

PURPOSE: After 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. METHODS: Between 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. RESULTS: A 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. CONCLUSIONS: Short-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.

OBJECTIVE: To assess the quality of screening mammograms performed in daily practice in the Quebec Breast Cancer Screening Program. SUBJECTS AND METHODS: Clinical 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. RESULTS: The 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/m(2) had a failure proportion of 67.5% compared with 34.9% for women with a BMI<25 kg/m(2) (risk ratio 2.1 [95% confidence interval, 1.5-3.0]). For positioning, women with a BMI ≥ 30 kg/m(2) had a failure proportion of 53.8% compared with 27.9% for women with a BMI < 25 kg/m(2) (risk ratio 1.9 [95% confidence interval, 1.2-3.1]). Effects of breast density on image quality differed among radiologists. CONCLUSION: Despite 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.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Contribution and performance of mobile units in an organized mammography screening program.

BACKGROUND: The aims of this study were to evaluate the contribution of mobile mammography units to participation rate and to compare their performance to fixed screening centres within the organized mammography screening program of Quebec, Canada. METHODS: The study is based on all screening mammograms carried out in women aged 50-69 who participated in the Québec program from 2002 to 2010. Performance was measured by screening sensitivity, false-positive rate (1-specificity), positive likelihood ratio as well as abnormal call rate, detection rate, interval cancer rate, positive predictive value, and tumour characteristics. Poisson regression models with robust variance estimation were used to take into account the multi-level structure of the data. All models were adjusted for characteristics related to women. RESULTS: During the 2002-2010 period, 2,292,592 screening mammograms were performed, of which 42,279 (1.8%) were in mobile units. In regions serviced exclusively by mobile units, the participation rate reached an average of 63.4% during the 2006-2010 period compared to 54.7% for the entire study population. Estimated sensitivity was similar to that of fixed sites (rate ratio = 0.98 [0.84-1.15]) while the false-positive rate was lower (rate ratio = 0.76 [0.57-1.02]) although this difference was of marginal statistical significance (p=0.07). CONCLUSIONS: In this program, mobile mammography units allowed regions lacking a fixed centre to attain participation rates slightly higher than those in the rest of Quebec, without loss of sensitivity and with some gain in the false-positive rate.

Factors associated with death in the emergency department among children dying of complex chronic conditions: population-based study.

OBJECTIVES: To determine the percentage of deaths occurring or confirmed in an emergency department (ED) among children dying of complex chronic conditions and identify factors associated with that percentage. METHODS: The population and variables of this population-based study were derived from three administrative databases. The study focuses on all children aged 1-19 years who died of complex chronic conditions in Quebec in 1997-2001. Children not hospitalized on seventh day before death were considered at risk of ED death at that time. The percentage of ED deaths was measured in association with year of death, sociodemographic characteristics, outpatient visits, and hospitalizations in the last 6 months of life. RESULTS: Among all 506 deaths, 13.8% died in an ED. Among the 300 children not hospitalized on the seventh day before death, 21.7% had an ED death. Compared to children dying from malignancies, the adjusted odds of ED deaths were higher for those with cardiovascular conditions (odds ratio [OR] = 6.3; 95% confidence interval [CI] = 2.3-17.5), metabolic and other congenital or genetic defect (OR = 4.5; 95% CI = 1.5-13.5) and neuromuscular conditions (OR = 3.7; 95% CI = 1.5-9.4). The adjusted odds of ED deaths increased over time and were lower for children with hospitalizations in tertiary pediatric centers (OR = 0.3; 95% CI = 0.1-0.8), compared to those with no hospitalization. CONCLUSIONS: EDs play an important role in end-of-life care of children with complex chronic conditions. Multidisciplinary teams of tertiary pediatric centers may be better able to assess prognosis and provide appropriate advanced care planning.