In case of endometrial cancer: after 15 minutes time-interval the surgical staging procedure starts with a TAH and BSO. After approximately 45 minutes the sentinel node(s) will be identified either by the radioactive tracer and / or visually (blue dye) after opening the retroperitoneal space. This 45 minutes time-interval is chosen to mimic the time interval when a frozen section is performed in case of an ovarian tumor. After removal of the sentinel node(s) a complete standard staging procedure will be performed including a comprehensive at random sampling of other lymph nodes at the different locations.