Radiotherapy effects on early breast cancer survival in observational and randomized studies: a systematic analysis of advantages, disadvantages and differences between the two study types
- Publication type:
- Journal article
- Metadata:
-
- Autoren
- Jochem Koenig
- Reyn van Ewijk
- Kathrin Kuhr
- Heinz Schmidberger
- Achim Woeckel
- Rolf Kreienberg
- Maria Blettner
- Autoren-URL
- https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=fis-test-1&SrcAuth=WosAPI&KeyUT=WOS:000374580800009&DestLinkType=FullRecord&DestApp=WOS_CPL
- DOI
- 10.1007/s12282-014-0579-2
- eISSN
- 1880-4233
- Externe Identifier
- Clarivate Analytics Document Solution ID: DK0CT
- PubMed Identifier: 25585654
- ISSN
- 1340-6868
- Ausgabe der Veröffentlichung
- 3
- Zeitschrift
- BREAST CANCER
- Schlüsselwörter
- Observational studies
- Randomized controlled trials
- Radiotherapy
- Breast cancer
- Radiotherapy
- Paginierung
- 415 - 424
- Datum der Veröffentlichung
- 2016
- Status
- Published
- Titel
- Radiotherapy effects on early breast cancer survival in observational and randomized studies: a systematic analysis of advantages, disadvantages and differences between the two study types
- Sub types
- Article
- Ausgabe der Zeitschrift
- 23
Data source: Web of Science (Lite)
- Other metadata sources:
-
- Autoren
- Jochem König
- Reyn van Ewijk
- Kathrin Kuhr
- Heinz Schmidberger
- Achim Wöckel
- Rolf Kreienberg
- Maria Blettner
- DOI
- 10.1007/s12282-014-0579-2
- eISSN
- 1880-4233
- ISSN
- 1340-6868
- Ausgabe der Veröffentlichung
- 3
- Zeitschrift
- Breast Cancer
- Sprache
- en
- Online publication date
- 2015
- Paginierung
- 415 - 424
- Datum der Veröffentlichung
- 2016
- Status
- Published
- Herausgeber
- Springer Science and Business Media LLC
- Herausgeber URL
- http://dx.doi.org/10.1007/s12282-014-0579-2
- Datum der Datenerfassung
- 2019
- Titel
- Radiotherapy effects on early breast cancer survival in observational and randomized studies: a systematic analysis of advantages, disadvantages and differences between the two study types
- Ausgabe der Zeitschrift
- 23
Data source: Crossref
- Abstract
- <h4>Aim</h4>Treatment-outcome associations often differ substantially between observational studies (OSs) and randomized controlled trials (RCTs). We investigate causes, focusing on radiotherapy (RT) effects in early breast cancer treatment, to better understand each study type's merits.<h4>Methods and materials</h4>We systematically analyzed three potential causes, by comparing data from a large OS with results from two previously published meta-analyses of RCTs: differences in patient populations combined with heterogeneous treatment effects, non-random treatment decisions in OSs, and differences in therapy administration.<h4>Results</h4>RT-survival associations were considerably stronger in our OS than in the RCTs, e.g., a hazard rate for overall survival after breast-conserving therapy of 0.57 in the OS vs 0.90 in the RCTs. The first proposed reason has limited relevance: patient populations differed considerably, but effect heterogeneity between patient groups was limited. The second reason does explain part of the difference: in the OS treatment decisions (being nonrandomized) and prospects differed with patient characteristics. Notably, patients with early recurrences or mortality are generally excluded from RCTs. Their inclusion in OSs leads to stronger treatment-outcome associations.<h4>Conclusion</h4>RCTs and OSs each have their own merits. While RCTs have their undisputed benefits, results from OSs that indicate that RT effects in early breast cancer are even stronger than those reported in RCTs should not be ignored.
- Addresses
- University Medical Centre, Institute for Medical Biostatistics, Epidemiology and Informatics, Johannes Gutenberg-University of Mainz, Mainz, Germany.
- Autoren
- Jochem König
- Reyn van Ewijk
- Kathrin Kuhr
- Heinz Schmidberger
- Achim Wöckel
- Rolf Kreienberg
- Maria Blettner
- DOI
- 10.1007/s12282-014-0579-2
- eISSN
- 1880-4233
- Externe Identifier
- PubMed Identifier: 25585654
- Open access
- false
- ISSN
- 1340-6868
- Ausgabe der Veröffentlichung
- 3
- Zeitschrift
- Breast cancer (Tokyo, Japan)
- Schlüsselwörter
- Humans
- Breast Neoplasms
- Combined Modality Therapy
- Logistic Models
- Comorbidity
- Adult
- Aged
- Middle Aged
- Female
- Meta-Analysis as Topic
- Randomized Controlled Trials as Topic
- Observational Studies as Topic
- Sprache
- eng
- Medium
- Print-Electronic
- Online publication date
- 2015
- Paginierung
- 415 - 424
- Datum der Veröffentlichung
- 2016
- Status
- Published
- Datum der Datenerfassung
- 2015
- Titel
- Radiotherapy effects on early breast cancer survival in observational and randomized studies: a systematic analysis of advantages, disadvantages and differences between the two study types.
- Sub types
- Research Support, Non-U.S. Gov't
- Journal Article
- Ausgabe der Zeitschrift
- 23
Data source: Europe PubMed Central
- Abstract
- AIM: Treatment-outcome associations often differ substantially between observational studies (OSs) and randomized controlled trials (RCTs). We investigate causes, focusing on radiotherapy (RT) effects in early breast cancer treatment, to better understand each study type's merits. METHODS AND MATERIALS: We systematically analyzed three potential causes, by comparing data from a large OS with results from two previously published meta-analyses of RCTs: differences in patient populations combined with heterogeneous treatment effects, non-random treatment decisions in OSs, and differences in therapy administration. RESULTS: RT-survival associations were considerably stronger in our OS than in the RCTs, e.g., a hazard rate for overall survival after breast-conserving therapy of 0.57 in the OS vs 0.90 in the RCTs. The first proposed reason has limited relevance: patient populations differed considerably, but effect heterogeneity between patient groups was limited. The second reason does explain part of the difference: in the OS treatment decisions (being nonrandomized) and prospects differed with patient characteristics. Notably, patients with early recurrences or mortality are generally excluded from RCTs. Their inclusion in OSs leads to stronger treatment-outcome associations. CONCLUSION: RCTs and OSs each have their own merits. While RCTs have their undisputed benefits, results from OSs that indicate that RT effects in early breast cancer are even stronger than those reported in RCTs should not be ignored.
- Date of acceptance
- 2014
- Autoren
- Jochem König
- Reyn van Ewijk
- Kathrin Kuhr
- Heinz Schmidberger
- Achim Wöckel
- Rolf Kreienberg
- Maria Blettner
- Autoren-URL
- https://www.ncbi.nlm.nih.gov/pubmed/25585654
- DOI
- 10.1007/s12282-014-0579-2
- eISSN
- 1880-4233
- Ausgabe der Veröffentlichung
- 3
- Zeitschrift
- Breast Cancer
- Schlüsselwörter
- Breast cancer
- Observational studies
- Radiotherapy
- Randomized controlled trials
- Adult
- Aged
- Breast Neoplasms
- Combined Modality Therapy
- Comorbidity
- Female
- Humans
- Logistic Models
- Meta-Analysis as Topic
- Middle Aged
- Observational Studies as Topic
- Randomized Controlled Trials as Topic
- Sprache
- eng
- Country
- Japan
- Paginierung
- 415 - 424
- PII
- 10.1007/s12282-014-0579-2
- Datum der Veröffentlichung
- 2016
- Status
- Published
- Datum, an dem der Datensatz öffentlich gemacht wurde
- 2017
- Titel
- Radiotherapy effects on early breast cancer survival in observational and randomized studies: a systematic analysis of advantages, disadvantages and differences between the two study types.
- Sub types
- Journal Article
- Research Support, Non-U.S. Gov't
- Ausgabe der Zeitschrift
- 23
Data source: PubMed
- Beziehungen:
- Property of