Text and Data Mining valid from 2019-06-10
Received: 22 November 2018
Accepted: 29 May 2019
First Online: 10 June 2019
Ethics approval and consent to participate
: This was a retrospective study and all data were collected according to the guidelines of the Ethics Committee in Cancer Hospital of Fudan University.
: Not applicable.
: The authors declare that they have no competing interests.