Received: 18 March 2020
Accepted: 4 May 2020
First Online: 13 May 2020
Ethics approval and consent to participate
: Informed consent was obtained from all individual participants included in the study. Since the patient information in the SEER database is deidentified and publicly available, our study was exempt from Institutional Review Board approval. This study was conducted in concordance with the Helsinki Declaration.
: Not applicable.
: The authors declare that they have no competing interests.