The role of cisplatin/bleomycin-based chemotherapy in the treatment of poorly differentiated carcinoma of unknown primary site.

Between 1978 and 1990, 173 patients with poorly differentiated carcinoma or poorly differentiated adenocarcinoma of unknown primary site were treated with bleomycin-containing regimens at Vanderbilt University Medical Center. Patients were prospectively identified based on light microscopy findings. The median age of patients was 39 years; 78% were male and 76% had metastatic tumors in two or more sites. Dominant tumor location was the mediastinum, retroperitoneum, or peripheral lymph nodes in 82 patients (47%). Between 1978 and 1985, patients received cisplatin 20 mg/m2 intravenously (IV) days 1 through 5, vinblastine 0.15 mg/kg IV days 1 and 2, and bleomycin 30 U IV weekly. In 1986, etoposide 100 mg/m2 IV days 1 through 5 replaced vinblastine in the regimen. Responding patients received four courses of therapy at 3-week intervals. One hundred thirteen patients (65%) had a major response to therapy, including 47 (27%) complete responses. At present, 27 patients are disease free at a median of 78 months posttherapy (range, 11 to 142 months); an additional patient was lost to follow-up while in complete response. Median survival of the entire group was 11 months, with a 12-year actuarial disease-free survival of 16%. Combination chemotherapy with cisplatin/bleomycin and either vinblastine or etoposide is highly active in patients with poorly differentiated carcinoma of unknown primary site and is curative in a minority of these patients. A trial of this therapy should be considered in all such patients.