1 Clinical Research Unit, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, Netherlands.
2 Department of Surgery, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, Netherlands.
3 Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, Netherlands.
4 Department of Surgery, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, 1105 AZ Amsterdam, Netherlands. Electronic address: m.g.besselink@amc.nl.