Song, Kehan
Song, Jian
Lin, Kaiyuan
Chen, Feiyan
Ma, Xiaosheng
Jiang, Jianyuan http://orcid.org/0000-0003-1684-2758
Li, Feng
Article History
Received: 16 September 2018
Accepted: 14 May 2019
First Online: 24 May 2019
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: Because we obtain data from the SEER database with open access, we did not need to acquire patient consent or an ethical review committee statement, but we were required to sign a Data Use Agreement for the SEER 1973–2014 Research Data File to gain access to the SEER database.