Text and Data Mining valid from 2019-10-20
Accepted: 29 August 2019
First Online: 20 October 2019
Compliance with Ethical Standards
: The authors declare that they have no conflicts of interest.
: De-identification of SEER data was done before release and they do not contain any personally identification information. As the data are publicly available, no ethical approval is required.
: As the data are publicly available, no informed consent is required.