Received: 3 November 2019
Accepted: 21 January 2020
First Online: 4 February 2020
Ethics approval and consent to participate
: This study used a general dataset from the Surveillance, Epidemiology, and End Results database built by a public health program, and therefore did not require institutional review board approval and the patients’ data were atomized.
: Not applicable.
: The authors declare that they have no competing interests.