Metastatic adenocarcinomas of unknown primary site. Prognostic variables and treatment results.

As part of a Phase II chemotherapy trial using mitomycin-C, adriamycin, and vindesine, 57 patients with adenocarcinoma of unknown primary site were assessed for prognostic variables predictive of response and survival. They were also evaluated for response and toxicity, usefulness of screening techniques, and eventual definition of primary site and pattern of progression. Only gender predicted response, with women being more likely to respond than men. Visceral metastases below the diaphragm, or the presence of liver metastases, predicted poor survival. Responding patients were highly likely to relapse first at sites of initial disease. Hemolytic-uremic syndrome was the most severe toxicity; other side effects were moderate. The response rate was 30% (three complete responders), which is similar to other current regimens. This study suggests that patients with better prognosis characteristics of single site of disease and without intraabdominal tumor may benefit from a policy of expectant observation after local control has been established. Patients with multiple sites of disease and/or intraabdominal tumor are appropriate candidates for investigational chemotherapy.