Over the last few decades there has been an increase in the use of strategies to detect clinically occult breast cancer with the aim of achieving diagnosis at an earlier stage when prognosis may be improved. Such strategies include screening mammography in healthy women, diagnostic imaging and axillary staging in those diagnosed with breast cancer, and the use of follow-up imaging for the early detection of recurrent or metastatic disease. Some of these strategies are established, whereas for others there are inconsistent supportive data. Although the potential benefit of early detection of clinically occult breast cancer seems intuitive, use of such strategies can also be associated with harm. In this commentary, we provide an extended discussion on the potential benefits and harms of the routine and frequent use of screening interventions to detect clinically occult breast cancer and question whether we may be causing more harm than good.
[Show abstract][Hide abstract] ABSTRACT: In this article, we discuss the most common epidemiological methods used for evaluating the ability of mammography screening to decrease the risk of breast cancer death in general populations (effectiveness). Case-control studies usually find substantial effectiveness. However when breast cancer mortality decreases for reasons unrelated to screening, the case-control design may attribute to screening mortality reductions due to other causes. Studies based on incidence-based mortality have obtained contrasted results compatible with modest to considerable effectiveness, probably because of differences in study design and statistical analysis. In areas where screening has been widespread for a long time, the incidence of advanced breast cancer should be decreasing, which in turn would translate into reduced mortality. However, no or modest declines in the incidence of advanced breast cancer has been observed in these areas. Breast cancer mortality should decrease more rapidly in areas with early introduction of screening than in areas with late introduction of screening. Nonetheless, no difference in breast mortality trends has been observed between areas with early or late screening start. When effectiveness is assessed using incidence-based mortality studies, or the monitoring of advanced cancer incidence, or trends in mortality, the ecological bias is an inherent limitation that is not easy to control. Minimization of this bias requires data over long periods of time, careful selection of populations being compared and availability of data on major confounding factors. If case-control studies seem apparently more adequate for evaluating screening effectiveness, this design has its own limitations and results must be viewed with caution.
See related Opinion article: http://www.biomedcentral.com/1741-7015/10/106 and Commentary http://www.biomedcentral.com/1741-7015/10/164
BMC Medicine 12/2012; 10(1):163. DOI:10.1186/1741-7015-10-163 · 7.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of screening programs is to discover life threatening diseases in as many patients as early as possible and to increase the chance of survival. To be able to compare aspects of health care quality, methods are needed for benchmarking that allow comparisons on various health care levels (regional, national, and international).
Applications and extensions of algorithms can be used to link the information on disease phases with relative survival rates and to consolidate them in composite measures. The application of the developed SAS-macros will give results for benchmarking of health care quality. Data examples for breast cancer care are given.
A reference scale (expected, E) must be defined at a time point at which all benchmark objects (observed, O) are measured. All indices are defined as O/E, whereby the extended standardized screening-index (eSSI), the standardized case-mix-index (SCI), the work-up-index (SWI), and the treatment-index (STI) address different health care aspects. The composite measures called overall-performance evaluation (OPE) and relative overall performance indices (ROPI) link the individual indices differently for cross-sectional or longitudinal analyses.
Algorithms allow a time point and a time interval associated comparison of the benchmark objects in the indices eSSI, SCI, SWI, STI, OPE, and ROPI. Comparisons between countries, states and districts are possible. Exemplarily comparisons between two countries are made. The success of early detection and screening programs as well as clinical health care quality for breast cancer can be demonstrated while the population’s background mortality is concerned.
If external quality assurance programs and benchmark objects are based on population-based and corresponding demographic data, information of disease phase and relative survival rates can be combined to indices which offer approaches for comparative analyses between benchmark objects. Conclusions on screening programs and health care quality are possible. The macros can be transferred to other diseases if a disease-specific phase scale of prognostic value (e.g. stage) exists.
BMC Public Health 01/2013; 13(1):34. DOI:10.1186/1471-2458-13-34 · 2.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Improvements in adjuvant therapy have led to a sustained fall in recurrences after early breast cancer. The differential reduction in local and systemic recurrences is poorly understood. This study aimed to explore changes in the distribution of loco-regional and distant recurrences in clinical trials reported over the last 20 years. We also aimed to determine the relative impact of adjuvant chemotherapy and endocrine therapy. MEDLINE search for adjuvant, phase III randomized breast cancer clinical studies between January 1990 and March 2011 was performed. Neoadjuvant, single agent biologics and studies that did not report the proportion of loco-regional and distant recurrences were excluded. The change in the frequency of recurrences was assessed as the nonparametric correlation between the number of loco-regional recurrences as a proportion of all recurrences and time. Studies were weighted by sample size. The differential effect of chemotherapy and endocrine therapy was also assessed. Fifty-three randomized clinical trials with a total of 86,598 patients were included in the analysis. Between 1990 and 2011, the proportion of loco-regional recurrences has decreased from approximately 30 to 15 % (Spearman's ρ = -0.40, p < 0.001). There was no interaction between type of surgery (mastectomy vs. lumpectomy), administration of adjuvant radiation therapy and menopausal status and the correlation of loco-regional recurrences and time. Chemotherapy regimen showed a larger negative correlation compared with endocrine therapy ( ρ = 0.49 vs. ρ = 0.24). Advances in treatment of early breast cancer have differentially reduced the proportion of loco-regional recurrences compared with distant recurrences. In recent trials, loco-regional recurrences account for less than 10-15 % of all recurrences. These falling event rates may affect patient care, especially when deciding on treatments influencing loco-regional control. This change may also impact on the design of clinical trials assessing loco-regional therapy such as surgery and/or local radiation therapy.
Breast Cancer Research and Treatment 05/2013; 139(2). DOI:10.1007/s10549-013-2561-7 · 3.94 Impact Factor
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