Management of patients with metastatic adenocarcinoma of unknown origin: a Southwest Oncology Group study

The Southwest Oncology Group evaluated 51 patients with a histologic diagnosis of metastatic adenocarcinoma and an occult primary tumor. Even though all patients received an extensive diagnostic evaluation, only six (12%) primary sites were found. Thirty-six patients whose primary tumor sites remained occult were randomized to receive either 5-FU or combination chemotherapy (5-FU, doxorubicin, and cyclophosphamide [FAC]). There were no responses in either group. The median survival with 5-FU was 105 days and with FAC was 95 days. Toxicity with FAC was more common and more severe.