Received: 23 December 2017
Accepted: 12 April 2018
First Online: 23 April 2018
Ethics approval and consent to participate
: This was a study based on register data. Survivors are informed about their participation and can afterwards withdraw their inclusion in the registry. Since the start of the registry in 1990 only a handful of patients have withdrawn their participation. Deceased patients are included without consent. The Regional Ethical Review Board in Stockholm, Sweden approved the study, Dnr 2013/1959-31/4.
: The manuscript does not contain individual person’s data, therefore consent for publications is not applicable.
: The authors declare that they have no competing interests.
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