Funding for this research was provided by:
Dutch cancer society (KUN 2011-5251)
Received: 17 May 2019
Accepted: 5 August 2019
First Online: 16 September 2019
Ethics approval and consent to participate
: The Institutional Review Board of the Radboud university medical center, Nijmegen, ruled that the current study does not require informed consent according to Dutch law, but based on national guidelines for the use of archival material, the Institutional Review Board agrees with the study proposal (CMO 2013/048, date 23/4/2013).
: Not applicable
: The authors declare that they have no competing interests.