Received: 9 January 2018
Accepted: 1 August 2018
First Online: 18 August 2018
Ethics approval and consent to participate
: The research has been approved by the Ethic Committee of the Japanese Orthopaedic Association on March 17, 2016. This was a retrospective study carried out using data from the Bone and Soft Tissue Tumor registry; the authors were not involved in the collection of this data. Patients were informed that their data would be used for research and their data were de-identified before addition to the database. Retrieval of the data from this database occurred in an unlinked fashion. As the data had been anonymized, the Ethical Guidelines for Epidemiological Research (Ministry of Education, Culture, Sports, Science and Technology, and Ministry of Health, Labour and Welfare of Japan), which require ethics approval and informed consent, are not applicable to this study. Based on the Ethical Guidelines on Biomedical Research Involving Human Subjects (Ministry of Education, Culture, Sports, Science and Technology, and Ministry of Health, Labour and Welfare of Japan), clinicoepidemiological studies conducted on medical databases constitute research carried out on pre-existing material and information, that did not require any interventions or interactions with patients. For such studies, including this study, obtaining written informed consent from patients is not compulsory.
: Not Applicable.
: The authors declare that they have no competing interests.
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