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Conclusions for mammography screening after 25-year follow-up of the Canadian National Breast Cancer Screening Study (CNBSS).

ABSTRACT: UNLABELLED:Twenty-five-year follow-up data of the Canadian National Breast Cancer Screening Study (CNBSS) indicated no mortality reduction. What conclusions should be drawn? After conducting a systematic literature search and narrative analysis, we wish to recapitulate important details of this study, which may have been neglected: Sixty-eight percent of all included cancers were palpable, a situation that does not allow testing the value of early detection. Randomisation was performed at the sites after palpation, while blinding was not guaranteed. In the first round, this "randomisation" assigned 19/24 late stage cancers to the mammography group and only five to the control group, supporting the suspicion of severe errors in the randomisation process. The responsible physicist rated mammography quality as "far below state of the art of that time". Radiological advisors resigned during the study due to unacceptable image quality, training, and medical quality assurance. Each described problem may strongly influence the results between study and control groups. Twenty-five years of follow-up cannot heal these fundamental problems. This study is inappropriate for evidence-based conclusions. The technology and quality assurance of the diagnostic chain is shown to be contrary to today's screening programmes, and the results of the CNBSS are not applicable to them. KEY POINTS:• The evidence base of the Canadian study (CNBSS) has to be questioned.• Severe flaws in the randomization process and test methods occurred. • Problems were criticized during and after conclusion of the trial by experts.• The results are not applicable to quality-assured screening programs. • The evidence base of this study must be re-analyzed.

SUBMITTER: Heywang-Kobrunner SH

PROVIDER: S-EPMC4712234 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature

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Conclusions for mammography screening after 25-year follow-up of the Canadian National Breast Cancer Screening Study (CNBSS).

Heywang-Köbrunner S H SH Schreer I I Hacker A A Noftz M R MR Katalinic A A

European radiology 20150528 2

<h4>Unlabelled</h4>Twenty-five-year follow-up data of the Canadian National Breast Cancer Screening Study (CNBSS) indicated no mortality reduction. What conclusions should be drawn? After conducting a systematic literature search and narrative analysis, we wish to recapitulate important details of this study, which may have been neglected: Sixty-eight percent of all included cancers were palpable, a situation that does not allow testing the value of early detection. Randomisation was performed a ...[more]

PMID: 26017741

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Project description:ObjectiveTo evaluate mammography screening quality on the Island of Jersey over a 25-year period from Jan 1990 to end March 2015 from females invited between ages 50 to 75 using a 2 yearly screening interval. Jersey had a population of only around 67,000 at onset, rising to around 100,000 at the end of the 25 years.MethodsAn analysis was performed of key routinely collected measures that are important to determining if a screening programme is on course to reduce breast cancer mortality such as uptake, recall rates, screen detected cancer and interval cancer rates. Further supporting indicators including grade, stage and comparative deaths from breast cancer in screen detected and not screen detected females were also assessed.ResultsOver the 25-year period 19,768 females were invited to screening and 16,866 attended, giving an uptake of 85.2%. There were 501 screen detected cancers of which 400 were invasive, and 101 DCIS. 125 interval cancers presented outside screening over the 25 years. The annual recall rate over the last 20 years was <6% for prevalent round and 4% for incident round screening. Based on the standardized detection ratio (SDR) and uptake, the estimated reduction in mortality from breast cancer was calculated as 40.2%.ConclusionsRecommended population sizes for breast units range from a quarter to half a million people. For very small units like Jersey serving smaller populations, rigorous quality control is essential to maintain credibility. Despite the small size of the programme evidence shows a similar detection rate to the UK NHS Breast screening programme was achieved. In small programmes careful monitoring of rates of uptake, recall, cancer detection and interval rates are required over adequate time periods together with supporting information to show that small units can achieve national standards and detection rates necessary to reduce breast cancer mortality.Advances in knowledgeRunning a small breast cancer screening programme is challenging for quality control. The impact on mortality can be predicted for small screening programmes despite their size. 10-year group survival in screen detected invasive breast cancer >90%. Interval cancers are more advanced than screen detected invasive cancers, so high suspicion is still required in breast symptoms after "normal" screen result. Mortality in lapsed/ceased attenders suggest that extending age range could be beneficial.

Project description:BACKGROUND:Debates about the benefits and harms of mammography continue despite the accumulation of evidence. We sought to quantify the disagreement across systematic reviews of mammography and determine whether author or design characteristics were associated with conclusions that were favourable to the use of mammography for routine breast cancer screening. METHODS:We identified systematic reviews of mammography published between January 2000 and November 2015, and extracted information about the selection of evidence, age groups, the use of meta-analysis, and authors' professions and financial competing interest disclosures. Conclusions about specific age groups were graded as favourable if they stated that there were meaningful benefits, that benefits of mammography outweighed harms, or that harms were inconsequential. The main outcome measures were the proportions of favourable conclusions relative to review design and author characteristics. RESULTS:From 59 conclusions identified in 50 reviews, 42% (25/59) were graded as favourable by two investigators. Among the conclusions produced by clinicians, 63% (12/19) were graded as favourable compared to 32% (13/40) from other authors. In the 50-69 age group where the largest proportion of systematic reviews were focused, conclusions drawn by authors without financial competing interests (odds ratio 0.06; 95% CI 0.07-0.56) and non-clinicians (odds ratio 0.11; 95% CI 0.01-0.84) were less likely to be graded as favourable. There was no trend in the proportion of favourable conclusions over the period, and we found no significant association between review design characteristics and favourable conclusions. CONCLUSIONS:Differences in the conclusions of systematic reviews of the evidence for mammography have persisted for 15 years. We found no strong evidence that design characteristics were associated with greater support for the benefits of mammography in routine breast cancer screening. Instead, the results suggested that the specific expertise and competing interests of the authors influenced the conclusions of systematic reviews.

Project description:BackgroundWhether timeliness of follow-up after abnormal mammography differs at facilities serving vulnerable populations, such as women with limited education or income, in rural areas, and racial/ethnic minorities is unknown.MethodsWe examined receipt of diagnostic evaluation after abnormal mammography using 1998-2006 Breast Cancer Surveillance Consortium-linked Medicare claims. We compared whether time to recommended breast imaging or biopsy depended on whether women attended facilities serving vulnerable populations. We characterized a facility by the proportion of mammograms performed on women with limited education or income, in rural areas, or racial/ethnic minorities.ResultsWe analyzed 30,874 abnormal screening examinations recommended for follow-up imaging across 142 facilities and 10,049 abnormal diagnostic examinations recommended for biopsy across 114 facilities. Women at facilities serving populations with less education or more racial/ethnic minorities had lower rates of follow-up imaging (4%-5% difference, P<0.05), and women at facilities serving more rural and low-income populations had lower rates of biopsy (4%-5% difference, P<0.05). Women undergoing biopsy at facilities serving vulnerable populations had longer times until biopsy than those at facilities serving nonvulnerable populations (21.6 vs. 15.6 d; 95% confidence interval for mean difference 4.1-7.7). The proportion of women receiving recommended imaging within 11 months and biopsy within 3 months varied across facilities (interquartile range, 85.5%-96.5% for imaging and 79.4%-87.3% for biopsy).ConclusionsAmong Medicare recipients, follow-up rates were slightly lower at facilities serving vulnerable populations, and among those women who returned for diagnostic evaluation, time to follow-up was slightly longer at facilities that served vulnerable population. Interventions should target variability in follow-up rates across facilities, and evaluate effectiveness particularly at facilities serving vulnerable populations.

Project description:CD44 is a transmembrane glycoprotein involved in numerous cellular functions, including cell adhesion and extracellular matrix interactions. It is known to be functionally diverse, with alternative splice variants increasingly implicated as a marker for tumor-initiating stem cells associated with poor prognosis. Here, we evaluate CD44 as a potential marker of long-term breast cancer outcomes. Tissue specimens from patients treated on the National Cancer Institute 79-C-0111 randomized trial of breast conservation versus mastectomy between 1979 and 1987 were collected, and immunohistochemistry was performed using the standard isoform of CD44. Specimens were correlated with patient characteristics and outcomes. Survival analysis was performed using the log rank test. Fifty-one patients had evaluable tumor sections and available long-term clinical follow up data at a median follow up of 25.7 years. Significant predictors of OS were tumor size (median OFS 25.4 years for ≤2 cm vs. 7.5 years for >2 cm, p = 0.001), nodal status (median OS 17.2 years for node-negative patients vs. 6.7 years for node positive patients, p = 0.017), and CD44 expression (median OS 18.9 years for CD44 positive patients vs. 8.6 years for CD44 negative patients, p = 0.049). There was a trend toward increased PFS for patients with CD44 positive tumors (median PFS 17.9 vs. 4.3 years, p = 0.17), but this did not reach statistical significance. These findings illustrate the potential utility of CD44 as a prognostic marker for early stage breast cancer. Subgroup analysis in patients with lymph node involvement revealed CD44 positivity to be most strongly associated with increased survival, suggesting a potential role of CD44 in decision making for axillary management. As there is increasing interest in CD44 as a therapeutic target in ongoing clinical trials, the results of this study suggest additional investigation regarding the role CD44 in breast cancer is warranted.

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Conclusions for mammography screening after 25-year follow-up of the Canadian National Breast Cancer Screening Study (CNBSS).

Publications

Conclusions for mammography screening after 25-year follow-up of the Canadian National Breast Cancer Screening Study (CNBSS).

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