1 Department of Surgery, Leiden University Medical Center, Leiden, Netherlands; Scientific Bureau, Dutch Institute for Clinical Auditing, Leiden, Netherlands. Electronic address: y.q.m.poelemeijer@lumc.nl.
2 Scientific Bureau, Dutch Institute for Clinical Auditing, Leiden, Netherlands; Department of Surgery, Academic Medical Center, Amsterdam, Netherlands.
3 Scientific Bureau, Dutch Institute for Clinical Auditing, Leiden, Netherlands; Department of Surgical Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands.