Most patients with newly diagnosed cancer are found to have a clearly defined primary tumour after initial investigation and staging. In England and Wales about 4% of these patients are found to have cancer without an identifiable primary site, despite exhaustive tests
Most patients who have malignancy without an identifiable primary site have tumours derived from epithelial cells, that is, carcinoma of unknown primary origin.
Current standard evaluation of cancer of unknown primary requires histopathologic evaluation and identification of favorable risk subtypes that can be more definitively treated or have superior outcomes (2)
Last edited 12/2020 and last reviewed 12/2020