Received: 5 October 2018
Accepted: 22 August 2019
First Online: 30 August 2019
Ethics approval and consent to participate
: We got approval from the National Cancer Institute to use data of patient from SEER database. Participant consent was not necessary as this study involved the use of a previously-published de-identified database according to SEER database.
: Not applicable.
: The authors declare that they have no competing interests.