ABSTRACT
INTRODUCTION Many cancer patients present with symptoms due to metastatic disease and the primary tumor site is detected by taking a careful history, clinical examination or occasionally by simple further investigations. However, a significant proportion of cancer patients, up to 8%, present with signs of metastatic cancer and detailed history, physical examination and laboratory investigations do not detect the primary tumor site. Patients who present in this way are described as having cancer from an unknown primary site. Over the past few years there has been considerable attention devoted to the characterization of this clinical syndrome and to the promulgation of strategies to identify those patients with treatable primary tumors from the majority in whom the benefits of therapy directed at the cancer are extremely limited. In this chapter, the clinical, laboratory and pathological features of patients with cancer from an unknown primary site are described, and a strategy for the efficient investigation and treatment of these patients is proposed.
