Risikoabschätzung in der Medizin am Beispiel der Krebsfrüherkennung

Was motiviert Frauen zur Teilnahme am Mammographiescreening? Ergebnisse einer qualitativen Analyse von Interviews

Einleitung

Die Teilnahmerate am Mammographiescreening beträgt derzeit ca. 49 %. Über die Gründe für Frauen, am Screening teilzunehmen, ist bisher zu wenig bekannt.

Material und Methoden

Für eine qualitative Studie wurden aus den Teilnehmerinnen einer Fragebogenstudie zum Einfluss verschiedener Informationsbroschüren auf die Teilnahmebereitschaft 8 Frauen für Interviews ausgewählt. Die Frauen wurden nach den Kriterien Teilnahmebereitschaft (6 ja, 2 nein), Bildung (6 hoch, 2 niedrig) und Entscheidungssicherheit (6 hoch, 2 niedrig) ausgewählt und im Jahr 2014 in problemzentrierten Einzelinterviews befragt. Sequenzen der Interviewtranskripte wurden in multidisziplinären Teams inhaltsanalytisch ausgewertet.

Ergebnisse

Alle interviewten Frauen hatten Mammographieerfahrung. Es wurden übergreifende Themen in sechs Kategorien identifiziert: Pflichtgefühl, Autonomie, Zweifel, Unsicherheit, Arzt/Ärztin, Institution. Die Frauen sahen in der Screeningteilnahme die Chance, einer möglichen Bedrohung durch Brustkrebs zu entgehen. Erfahrungen mit Brustkrebs im Umfeld beeinflussten ihre Entscheidung. Einer selbstverantwortlichen Entscheidungsbildung wurde ein hoher Stellenwert zugesprochen, andererseits folgten sie dem Rat ihres Arztes/ihrer Ärztin. Bei der Durchführung des Screenings fühlten sie sich einer unpersönlichen und schmerzhaften Maschinerie ausgesetzt.

Schlussfolgerungen

Frauen treffen ihre Entscheidung, am Screening teilzunehmen oder nicht, eher auf der emotionalen Ebene. Um ihnen eine informierte Entscheidung zu ermöglichen, sollten in einem ärztlichen Gespräch neben sachlichen Informationen ihre Vorstellungen und Erfahrungen in Bezug auf das Mammographiescreening ergebnisoffen besprochen werden.

Studies for the Evaluation of Diagnostic Tests–Part 28 of a Series on Evaluation of Scientific Publications

BACKGROUND

The accurate diagnosis of a disease is a prerequisite for its appropriate treatment. How well a medical test is able to correctly identify or rule out a target disease can be assessed by diagnostic accuracy studies.

METHODS

The main statistical parameters that are derived from diagnostic accuracy studies, and their proper interpretation, will be presented here in the light of publications retrieved by a selective literature search, supplemented by the authors' own experience. Aspects of study planning and the analysis of complex studies on diagnostic tests will also be discussed.

RESULTS

In the usual case, the findings of a diagnostic accuracy study are presented in a 2 × 2 contingency table containing the number of true-positive, true-negative, false-positive, and true-positive test results. This information allows the calculation of various statistical parameters, of which the most important are the two pairs sensitivity/ specificity and positive/negative predictive value. All of these parameters are quotients, with the number of true positive (resp. true negative) test results in the numerator; the denominator is, in the first pair, the total number of ill (resp. healthy) patients, and in the second pair, the total number of patients with a positive (resp. negative) test. The predictive values are the parameters of greatest interest to phy - sicians and patients, but their main disadvantage is that they can easily be misinterpreted. We will also present the receiver operating characteristic (ROC) curve and the area under the curve (AUC) as additional important measures for the assessment of diagnostic tests. Further topics are discussed in the supplementary materials.

CONCLUSION

The statistical parameters used to assess diagnostic tests are primarily based on 2 × 2 contingency tables. These parameters must be interpreted with care in order to draw correct conclusions for use in medical practice.

Statistical literacy and scientific reasoning & argumentation in physicians

Objective: Statistical literacy (SL) of physicians, i.e. the ability to use and interpret statistical numbers in the context of science, is an essential prerequisite for risk estimation and communication. Together with scientific reasoning and argumentation (SRA) skills, SL provides the basis for evidence-based practice. Several studies suggest that in medical students both skills are underdeveloped. The aim of the present study was to investigate these skills in practicing physicians and how these skills were acquired. Methods: Data collection in N=71 physicians was conducted online and as paper pencil. SL was assessed with multiple-choice items. SRA skills evidence evaluation and drawing conclusions were measured with a decision scenario. Results: Study results indicated that physicians have medium levels of SL (M=17.58, SD=6.92, max 30 pts.) and SRA (evidence evaluation: M=7.75, SD=1.85, max 10 pts.; drawing conclusions: M=37.20, SD=5.35, max 60 pts.). Skills development via autodidactic learning activities (M=4.78, SD=1.13, range 1-6) was reported significantly more often than development during formal medical education (M=2.31, SD=1.46), t(71)=-9.915, p<.001, or in extracurricular activities (M=3.34, SD=1.87), t(71)=4.673, p<.001. The active involvement in research seemed decisive: The number of publications and time spent in research significantly correlated with SL, r(71)=.355, p=.002; respectively r(71)=.280, p=.018. SRA skills were predicted by the type of MD-thesis, β=-.380, p=.016, and working in research, β=3.355, p=.008. Conclusion: Active involvement in research activities seems to be a very important factor for the development of both SL and SRA skills. The implementation of systematic fostering of these skills during formal medical education seems warranted.

[Health services research : Definition, objective, method and perspectives]

This overview article highlights the central role of health services research (HSR) for the further development of the healthcare system. As a young scientific discipline in Germany, HSR covers five important elements with different weighting in different definitions, which are elaborated in some detail in this article: patient orientation, results and outcome orientation at the patient and population levels, implementation perspectives and context relation, complex interventions and improvement, multidisciplinarity and multiprofessionalism. One of the fundamental pillars of HRS is related to the insufficient implementation of scientifically proven treatment methods and improvement strategies into routine patient care. Healthcare research is therefore the so-called second translation of clinical trials in the routine daily care (from bedside to practice) after the first translation from bench to bedside. The scientific methods used in HSR clearly extend beyond the spectrum of (clinical) epidemiology. The methodological standards are developed as consensus memoranda of members of the German network of HSR, which serve as orientation points for qualitatively good HSR. Finally, various perspectives for the long-term safeguarding and improvement of the quality of HSR in Germany are proposed.

[Cancer screening from the perspective of public health ethics]

Cancer screening programs aim at reducing the tumor-related morbidity and mortality by early detection of malignant tumors or precancerous lesions. The basic ethical dilemma in cancer screening is, however, that many people have to be exposed to the burdens and risks of the intervention for a few people to benefit from early cancer diagnosis. This article discusses under which conditions it is ethically acceptable to offer or even recommend cancer screening. First, the benefit of the program in terms of a reduced cancer-related mortality should be proven by randomized controlled trials. The risks and burdens of the program related to the side effects of the investigation itself, false-positive findings, as well as overdiagnoses and overtherapy should be in an acceptable relationship to the expected benefit of the program. In addition to a solid empirical scientific basis, the benefit-harm evaluation necessarily involves value judgments. The potential participants in the screening program therefore should receive transparent, objective, unbiased, and understandable information to enable them to make a truly informed choice about participation. Given the complex benefit-risk assessment, it is discussed whether-and if so under which circumstances-it is ethically acceptable to make a recommendation for or against participation in a cancer screening program. Socioempirical research, such as focus group studies and public deliberations, can be used to elicit the preferences and value judgments of members of the target population that should be taken into consideration in recommendations about a cancer screening program.

"There is nothing to worry about": gynecologists' counseling on mammography

OBJECTIVE

In Germany, approximately 10 million women between the ages of 50 and 69 are eligible for biennial mammography screening. Mammography is at the center of much controversy, however, which means gynecologists must provide women considering mammography with sufficient and transparent information. The present study analyzed the information gynecologists share with a person seeking advice about the benefit and harms of mammography screening.

METHOD

To receive realistic data, we called 20 gynecologists practicing in different large cities across Germany and took telephone counseling sessions on the benefit and harms of mammography.

RESULTS

The majority of gynecologists described mammography as safe and scientifically well grounded. Harms were rarely mentioned or described as negligible. A minority of gynecologists provided numerical information; when they did, they often quantified the benefit using relative risk reduction and harms using absolute risk increase.

CONCLUSION

A sample of German gynecologists was not able to correctly and transparently communicate the benefit and harms of mammography screening to a patient.

PRACTICE IMPLICATION

Gynecologists should be taught how to understand and transparently explain medical risk information in simple terms.