Received: 10 June 2018
Accepted: 11 February 2019
First Online: 26 February 2019
Ethics approval and consent to participate
: The multicenter data collection and analysis was approved by the Ethics committee of the Kanton Zurich, Switzerland (BASEC-Nr. 2016–00744) and in addition to local regulations also covered the following institutions:OrderedList removedIf necessary, the data collection of the individual participating centers was approved according to local regulations and approved by the respective local ethics committees. The following ethics committees and regulatory bodies were involved in this local approval process:OrderedList removedThe participants consent was written as part of the main ethics approval.
: Not applicable.
: Marciana Duma and Christian Ostheimer are members of the editorial board (Associate editors) of BMC Cancer. NA confirms that all other authors have nothing to declare at the time of submission and that there are no competing interests to declare.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.