Received: 13 February 2017
Accepted: 16 January 2018
First Online: 24 January 2018
Ethics approval and consent to participate
: According to the Central Committee on Research involving Human Subjects (CCMO), this type of study does not require approval from an ethics committee in the Netherlands. This study was approved by the Privacy Review Board of the Netherlands Cancer Registry. All cancer patients are opted-in in the Netherlands Cancer Registry as defined by Dutch law, unless patients object to this. No formal consent is required.
: Not applicable.
: The authors declare that they have no competing interests.
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