Tanaka, Toshimichi
Ozawa, Heita http://orcid.org/0000-0001-9318-3181
Nakagawa, Yusuke
Hirata, Akira
Fujita, Shin
Sugihara, Kenichi
Article History
Accepted: 16 September 2019
First Online: 3 December 2019
Compliance with ethical standards
: This study was conducted in accordance with the Declaration of Helsinki and with the approval of the Research Ethics Committee of Tochigi Cancer Center. Informed consent for this research was substituted by a consent form at each of the participant’s institutes, because of the retrospective study design.
: The authors declare that they have no conflict of interest.
: Ethics approval was obtained from the Tochigi Cancer Center’s institutional review board, and for this type of study, formal consent is not required.