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.

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.

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.

Standard Period Life Table Used to Compute the Life Expectancy of Diseased Subpopulations: More Confusing Than Helpful.

Life expectancy (LE) based on a period life table (PLT) traditionally serves as a general population summary metric. It is, however, becoming more frequently reported for chronically afflicted subpopulations. In general populations, there is always an obvious real cohort sharing the hypothetical PLT cohort characteristics, and the LE estimate is intuitively understood as that real cohort mean survival time, assuming constancy of death risks. In diseased subpopulations, the correspondence between the hypothetical cohort and a real cohort is not straightforward. Furthermore, the excess mortality of chronic diseases usually changes according to age at onset and time since onset. The standard PLT method does not allow for proper control of these issues, so the LE estimate can only be deemed valid under specific assumptions. Without clear statements about the real cohort to whom the estimate is intended and the assumptions allowing disregard of the effect of age at onset and time since onset, LEs of afflicted subpopulations computed with the PLT are only abstract numbers summarizing mortality rates. If called "life expectancy," they can be seriously misleading. The same applies to health-adjusted LE.

Antihypertensive drug use and the risk of prostate cancer (Canada).

PURPOSE: To verify if exposure to antihypertensive drugs was associated to prostate cancer (PC) risk. METHODS: We conducted a matched case-control study using record linkage between two population-based databases. We defined exposure as a binary variable and in terms of timing and cumulative duration of use. We controlled for detection bias and Aspirin use. RESULTS: Among the 2221 cases and 11,105 controls, use of any antihypertensive agent was associated with an adjusted relative risk of PC of 0.98 (CI, 0.88-1.08). Of the different classes of antihypertensives, only beta-blockers (BBs) were associated with a reduction in PC risk (OR = 0.86, CI = 0.77-0.96). In those who cumulated < 1, 1-4, and > or = 4 years of BB use, the risk was 0.89 (0.75-1.05), 0.91 (0.75-1.09), and 0.82 (0.69-0.96), respectively. Also, subjects with > or = 4 years of alpha-blocker (ABs) use had a non-significant 25% reduction in PC risk. CONCLUSIONS: Our results suggest that BBs and long-term use of ABs may prevent PC whereas calcium channel blockers or angiotensin-converting enzyme inhibitors do not influence PC risk.

Dosage, duration and timing of nonsteroidal antiinflammatory drug use and risk of prostate cancer.

Experimental studies suggest that NSAIDs could reduce prostate cancer risk. Results of observational studies on the relation between NSAIDs and prostate cancer risk have, however, been inconsistent. Moreover, none has addressed the issues of dosage, duration and timing of exposure. In a population-based, age-matched case-control study, we measured the association between prostate cancer risk and NSAIDs defined in terms of mean daily dose, cumulative duration and timing of exposure. Eight-year drug exposure history was obtained from the Quebec health insurance system database. Parallel analyses were performed for aspirin and NSAIDs other than aspirin. We controlled for detection bias and assessed the potential impact of protopathic bias. Analyses were performed with conditional logistic regression. Among the 2,221 cases and 11,105 controls, there was a negative trend between cumulative duration of aspirin use and prostate cancer risk (p = 0.0009). Also, exposure to a mean daily dose of aspirin of at least 80 mg, maintained throughout the entire 8 years of follow-up, was associated with an 18% reduction in prostate cancer risk (OR = 0.82, 95% CI 0.71-0.95). In more recent users of such a dose, the risk reduction was 7%. However, 1 year after the end of a 7-year regular aspirin exposure, no residual protective effect persisted. No association was observed between prostate cancer risk and exposure to NSAIDs other than aspirin. The results suggest that long-term and regular use of aspirin, at a dosage beneath that usually recommended for an anti-inflammatory effect, may prevent prostate cancer.

PSA screening and prostate cancer mortality.

BACKGROUND: Physicians have speculated that prostate-specific antigen (PSA) screening may be responsible for the reduction in prostate cancer mortality observed in the late 1 990s. In order to test this hypothesis, we assessed the relation between the change in prostate cancer incidence in the early 1990s, attributed largely to PSA screening, and the subsequent change in prostate cancer mortality. METHODS: We divided the adult male population of Quebec aged 50 years and more into 15 birth cohorts. For each birth cohort, we computed the change in prostate cancer incidence between 1989 and 1993 and the change in prostate cancer mortality between 1995 and 1999. We then assessed the correlation between the changes in prostate cancer incidence and the subsequent changes in prostate cancer mortality by weighted linear regression. We also split up the study population into 15 regional populations and repeated the analysis described above. RESULTS: We found that even though most birth cohorts showed an increase in prostate cancer incidence and a subsequent decrease in mortality, the sizes of these changes were not inversely correlated (Pearson's r = 0.33, 1-sided p = 0.89). Similarly, in the regional population study, we found that a greater increase in prostate cancer incidence did not indicate a greater decline in mortality (Pearson's r= 0.13, 1-sided p = 0.68). INTERPRETATION: These results suggest that for our study population PSA screening was not associated with, and therefore cannot explain, the decline in prostate cancer mortality.