Purpose: To compare the results of empiric first-line therapy with paclitaxel/carboplatin/etoposide (PCE) versus gemcitabine/irinotecan, both followed by single-agent gefitinib, in patients with carcinoma of unknown primary site.
Patients and methods: Patients with previously untreated carcinoma of unknown primary site were randomized to receive either PCE or gemcitabine/irinotecan. Responding and stable patients continued treatment for 4 to 6 cycles. Patients with no evidence of tumor progression at that time received single-agent gefitinib until tumor progression. The trial was designed to detect an improvement in the 2-year survival rate from 20% to 30%.
Results: Between September 2003 and July 2008, 198 patients entered this multicenter, community-based trial. Because of slow accrual, the trial was stopped short of its target accrual of 320 patients. Clinical characteristics were comparable for patients receiving PCE (N = 93) and gemcitabine/irinotecan (N = 105). PCE and gemcitabine/irinotecan produced similar 2-year survival (15% vs. 18%), median survival (7.4 months vs. 8.5 months), median progression-free survival (3.3 months vs. 5.3 months), and response rate (18% vs. 18%). Grade 3/4 neutropenia, thrombocytopenia, anemia, febrile neutropenia, and red blood cells transfusions were more common with PCE; diarrhea was more common with gemcitabine/irinotecan. The median duration of gefitinib maintenance was 3 months, suggesting no role as a maintenance therapy in this setting.
Discussion: The PCE and gemcitabine/irinotecan regimens have comparable efficacy in the first-line treatment of patients with carcinoma of unknown primary site. Gemcitabine/irinotecan is the preferable regimen, due to its favorable toxicity profile. However, the moderate efficacy of both regimens underscores the need for novel treatment approaches in this patient population.