[Limit investigation in cancer of unknown primary site]

Cancer of unknown primary (CUP) is relatively common, approximately 3-5% of all cancers. Diagnostic evaluation must include adequate tumor biopsies for pathology evaluation (PAD) as well as abdominal and chest CT. Prognosis is generally poor, but subgroups occur where long-term survival is possible, and a few patients can even be cured. If patients do not belong to any of these subgroups, diagnostic evaluation and treatment should be considered in relation to possible benefits. CUP diagnosed patients should, if possible, be cared for by experienced hospital units with access to a multi-disciplinary network. New radiological methods, such as PET and whole-body MRI, may in certain cases provide important information for diagnosis.