Funding for this research was provided by:
National Research Foundation of Korea (2016R1E1A1A0191433)
Samsung Medical Center (SMX1170501)
Article History
Received: 24 March 2019
Accepted: 16 December 2019
First Online: 6 January 2020
Ethics approval and consent to participate
: The study did not require IRB by the Samsung Medical Center Human Subjects Institutional Review Board.
: Consent to publish is not applicable as human subjects were not recruited, and we used public and de-identified data from the webpage of the Surveillance, Epidemiology, and End Results Program.
: The authors declare that they have no competing interests.