1 Department of Surgery, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, Netherlands.
2 Department of Surgery, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, Netherlands. Electronic address: b.l.van.leeuwen@umcg.nl.
3 Department of Medical Oncology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, Netherlands.