Funding for this research was provided by:
KWF Kankerbestrijding (2014-7000)
Text and Data Mining valid from 2018-01-29
Received: 12 October 2017
Accepted: 8 January 2018
First Online: 29 January 2018
Compliance with ethical standards
: The authors declare that there is no conflict of interest.
: In all studies that were included in this systematic review, it was declared that all procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1964 and later versions. Also, in all studies it was declared that informed consent or a substitute for it was obtained from all patients before they were included in the studies.