Empirical Comparison of the Results of Randomized Controlled Trials and Case-Control Studies in Evaluating the Effectiveness of Screening Mammography (original) (raw)
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Epidemiology, Prevention, Screening
European Journal of Cancer, 2014
Background: Over 90% of mammography machines in Japan have already become digital, however, almost three-fourths of them utilize computed radiography (CR). The majority of them necessitate hard copy diagnosis. Therefore, reliability of soft-copy interpretation of CR mammography is still controversial. The purpose of this study is to assess the usefulness and problems of soft-copy interpretation of CR mammography in breast cancer screening retrospectively. Materials and Methods: We took CR mammograms of 44,058 women with PCM system (Konica Minolta) and digitized them with Regius Model 190 (Konica Minolta) at Kochi Kenshin Clinic and transferred them to Kochi Medical School via optic fiber (provided by NTT and STNet) between July 2005 and Aug. 2012. We interpreted them using two kinds of mammography viewing system: SenoAdvantage (GEYM) and a viewer produced by Carestream Health Care Inc. with a couple of 5M-pixel monitors and reported the results of interpretations through the same network. We introduced digital mammography systems with flat panel detector (FPD) (Amulet, FUJI) into our systems. We researched the process indexes of our mammographic screening program using CR softcopy for 7 years. And we compared the usability of CR soft-copy diagnosis with FPD. Results: The recall rate of our mammographic screening with CR softcopy was 5.3%, the cancer detection rate 0.27%, the positive predictive value is 5.1%. These process indexes are almost equivalent to the other mammographic screening programs using film-screen (F/S) in Japan. 28,293 (64.2%) were repeated screenees in our program. Moreover, we could know only 82.8% of the all diagnoses of recalled screenees. The size of digital data of our CR systems is too large, 135 Mb for one mammogram, to interpret rapidly using a usual client server. Furthermore, the characteristics of CR soft-copy are partially unsuitable for monitor diagnosis in comparison with FPD. Conclusions: Soft-copy interpretation of CR mammography has some limitations compared with FPD. However, the results of mammographic screening using that were not inferior to the conventional F/S systems. The CR soft-copy interpretation is still useful in mammographic screening in the regions where the majority of mammography is CR as Japan. No conflicts of interest 110A Poster Higher levels of HNE are associated with disease aggressiveness and worse outcome in breast cancer patients
Randomized study of mammography screening — preliminary report on mortality in the stockholm trial
Breast Cancer Research and Treatment, 1991
In March 1981, 40,318 women in Stockholm, aged 40-64, entered a randomized trial of breast cancer screening by single-view mammography alone versus no intervention in a control group of 20,000 women. The attendance rate during the first screening round was 81 per cent and the cancer detection rate was 4.0 per 1000 women. The detection the rate fell to 3.1 per 1000 in the second round, which was completed in October 1985. During 1986 the controlled design of the study was broken and the control women were invited once to screening which was completed the same year. A total of 428 cases of breast cancer were thus diagnosed in the study group and 439 in the adjusted control group. After a mean follow-up of 7.4 years the number of breast cancer deaths in the study and control groups was 39 and 30 respectively. The relative risk of breast cancer death (screening versus control) was 0.71 (95 per cent confidence interval: 0.4-1.2). Among women older than 50 years at entry the relative risk was 0.57 (95 per cent confidence interval: 0.3-1.1). Cancer deaths among women under 50 were few and perhaps because of this no mortality reduction was seen in this age group. The estimate of mortality reduction lies between the results from two earlier Swedish randomized controlled trials.
JNCI Monographs
The purpose of this overview is to estimate more precisely the long-term effect of mammography screening by adding four more years of follow-up to women aged 40-49 years in the four Swedish trials on mammography screening. Data from the four trials were merged and linked to the Swedish Cancer and Cause of Death Register for 1958-1993 and 1951-1993 respectively to identify date of breast cancer diagnosis and cause and date of death. The invited and control groups comprised 48,569 and 40,247 women respectively. At the December 1993 follow-up, 602 and 482 breast cancer cases were identified in the two groups respectively, of which 104 and 111 had breast cancer as the underlying cause of death. This corresponds to a relative risk (RR) of 0.77 (95% CI: 0.59-1.01) for the two groups. In the 40-44 age group at randomization, 94% of breast cancer patients in the study and 89% in the control group were diagnosed before the age of 50; however, among breast cancer deaths in this age group, only two in the invited and five in the control group died after age 50. At follow-up of women 40-44 years at randomization 208 women in the invited and 184 in the control group were reported to the Cancer registry with breast cancer. Out of these 195 (94%) and 163 (89%) respectively were reported before the age of 50. Further, the relative risk for the age group 40-44 years at randomization by age at follow-up was 1.11, 0.51 and 0.46 for the age groups 45-49, 50-54, and 55-59 at follow-up. This study shows a 23% reduction in the breast cancer mortality in women 40-49 years at randomization achieved from a median trial time of 7.0 years, a median follow-up time of 12.8 years, and a screening interval of 18-24 months. Almost all of the effect in the 40-44 year age group at randomization was due to screening before the age of 50.
The breast journal, 2016
The U.S. Preventive Services Task Force (USPSTF) recommended screening mammography every 1-2 years for women 40 years and older in 2002, and changed its recommendations in 2009 to no routine screening for women between 40 and 49 years of age; and biennial screening for women between 50 and 74 years of age. This study evaluates the change in mammographic use after the issuance of the revised recommendations. Women who participated in a cross-sectional study of breast cancer risk factors from 2007 to 2013 were asked if they had received a mammogram in the preceding 2 years. All 3442 study participants who enrolled in the study after January 1, 2011 were matched by race, age, and educational level with women enrolled between 2007 and 2010. The proportions of women who stated they had received a mammogram in the past 2 years were compared between the two groups. One fourth of the participants were African American and 39% were 40-49 years of age. Among white women, significant decreases...
Systematic reviews highlight the complex balance between good and harm from screening studies
Internal and Emergency Medicine, 2007
Background Mammographic screening for breast cancer is controversial, as reflected in greatly varying national policies. p Objectives The objective was to assess the effect of screening for breast cancer with mammography on mortality and morbidity.Search strategy MEDLINE (16 May 2000), The Cochrane Breast Cancer Group’s trial register (24 Jan 2000) and reference lists. Letters, abstracts and unpublished trials. Authors were contacted.Selection criteria Randomised trials comparing mammographic screening with no mammographic screening.Data collection and analysis Data were extracted by both authors independently.Main results Seven completed and eligible trials involving half a million women were identified. The two best trials provided medium-quality data and, when combined, yield a relative risk for overall mortality of 1.00 (95% CI 0.96–1.05) after 13 years. However, the trials are underpowered for all-cause mortality, and confidence intervals include a possible worthwhile effect as we ...
Trials, 2013
Background: The objective of our meta-analysis and systematic review was to analyze non-breast cancer mortality in women screened with mammography versus non-screened women to determine whether there is excess mortality caused by screening. Methods: We searched PubMed and the Web of Science up to 30 November 2010. We included randomized controlled trials with non-breast cancer mortality as the main endpoint. Two authors independently assessed trial quality and extracted data. Results: There was no significant difference between groups at 13-year follow-up (odds ratio = 1.00 (95% CI 0.98 to 1.03) with average heterogeneity I 2 = 61%) regardless of the age and the methodological quality of the included studies. The meta-analysis did not reveal excess non-breast cancer mortality caused by screening. If screening does have an effect on excess mortality, it is possible to provide an estimate of its maximum value through the upper confidence interval in good-quality methodological studies: up to 3% in the screened women group (12 deaths per 100,000 women). Conclusions: The all-cause death rate was not significantly reduced by screening when compared to the rate observed in unscreened women. However, mammography screening does not seem to induce excess mortality. These findings improve information given to patients. Finding more comprehensive data is now going to be difficult given the complexity of the studies. Individual modeling should be used because the studies fail to include all the aspects of a complex situation. The risk/benefit analysis of screening needs to be regularly and independently reassessed.
Cancer medicine, 2018
Breast cancer is the most common cancer diagnosis and the leading cause of cancer death among women in the world, and differences across populations indicate a role of hormonal, reproductive and lifestyle factors. This study is based on a cohort of 78,050 women invited to undergo a mammogram by Local Health Authority of Milan, between 2003 and 2007. We carried out a nested case-control study including all the 3303 incident breast cancer cases diagnosed up to 2015, and 9909 controls matched by age and year of enrollment. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using logistic regression models. The ORs were 0.88 (95% CI: 0.78-0.98) for an age at menarche ≥14 years and 1.39 (95% CI: 1.07-1.81) for an age of 30 years or older at first pregnancy. Body mass index (BMI) was positively associated with breast cancer risk in women older than 50 years (OR = 1.89, 95% CI: 1.54-2.31, for BMI≥30 vs. <20), while the association tended to be inverse in y...