Radiographic Studies, Endoscopy, and Serum Tumor Markers in the Diagnostic Evaluation of Carcinomas of Unknown Primary Site

The identification of a primary site of origin is the initial step in the formulation of the plan of treatment and in the determination of prognosis for oncology patients. When metastatic disease is documented in the absence of a clear primary site, a careful selection of the diagnostic tests to be performed is of paramount importance to maximize the chances of identifying the primary tumor and to minimize treatment delay, patient risk, inconvenience, and costs associated with a lengthy and redundant work-up.