ANALYSIS OF A DIAGNOSTIC STRATEGY FOR PATIENTS WITH SUSPECTED TUMORS OF UNKNOWN ORIGIN

Purpose: Diagnostic strategies designed to identify the underlying pri mary malignancies in patients with unknown primary tumors (UPTs) have relied on retrospective analyses. We analyzed 879 consecutive patients referred with suspected UPTs to determine the yield and cost of a lim ited diagnostic evaluation, assess the contribution of specific studie s to diagnosis, and analyse the survival patterns of patients in whom the primary tumor was diagnosed. Patients and Methods: Data from patie nts with a suspected UPT were entered into a computerized data base, a nd the patients underwent a predefined limited diagnostic evaluation. Primary malignancies were diagnosed by pathologic review alone or by p athologic criteria plus a physical or radiographic finding. Survival w as measured from diagnosis, estimated using the Kaplan-Meier method, a nd compared using the Cox-Mantel log-rank test. Results: A primary tum or was found in 179 of 879 patients (20%). The survival duration of pa tients in whom the primary tumor was diagnosed was superior to that of patients in whom the primary tumor remained unknown. Specific patient subsets contributed most to the improved survival duration of the gro up in which the primary tumor was found, including lymphoma patients d iagnosed solely by pathologic criteria and female patients with primar y breast or ovarian cancer. The cost of diagnosis was mostly due to th e extensive use of computed tomography. Except for ovarian cancer, com puted tomography rarely identified treatable primary tumors. Conclusio n: The limited diagnostic evaluation used in this study identified pat ients with treatable malignancies and increased the survival duration of a population of suspected UPT patients. Primary malignancies with t he best survival can be diagnosed through careful pathologic review an d focused evaluations for breast and ovarian cancer in women. (C) 1995 by American Society of Clinical Oncology.