Received: 24 April 2019
Accepted: 21 November 2019
First Online: 28 November 2019
Ethics approval and consent to participate
: The study was approved by the ethics committee of the University of Lübeck (reference number: 18-254A). The study was conducted in accordance with the principles laid out in the Declaration of Helsinki and in accordance with the principles of Good Clinical Practice.
: Not applicable.
: D.R. and S.J. are associate editors of BMC Cancer. Otherwise, the authors declare that they have no competing interest related to the study presented here.