A phase II study of cisplatin plus S-1 in patients with carcinomas of unknown primary site.

Abstract

e13620 Background: Carcinomas of unknown primary site (CUP) represent a group of heterogeneous tumors and accounts for about 5% of all cancer patients (pts). The prognosis of CUP is generally poor with a median overall survival time (OS) of 4 to 6 months, and no standard chemotherapy has been established. S-1 is a new oral fluoropyrimidine and shows broad efficacy for many carcinomas. Therefore, we conducted a phase II study of novel combination chemotherapy using cisplatin (CDDP) plus S-1 in pts with CUP to evaluate the efficacy and safety. Methods: The treatment schedule included CDDP given intravenously on day 8, and S-1 given orally twice a day on days 1-21, every 5 weeks. The primary endpoint was objective response rate, and secondary endpoints included safety, OS, and 1-year survival rate. Results: A total of 46 chemotherapy naïve pts were enrolled. Median age of pts was 63 years (range 31-84). There were twenty-five male. Twenty-three pts had adenocarcinoma, fourteen had squamous cell carcinoma, three had poorly differentiated carcinoma, and three had poorly differentiated adenocarcinoma. Eighteen pts presented with nodal metastasis only, and twenty-two with nodal and multiple organ metastasis. The median number of courses was four. The overall response rate and the disease control rate were 41.3% and 80.4%, respectively. (CR/PR/SD/PD/NE; 2/17/18/7/2) The median progression-free survival time and the overall survival time were 7.5 months and 17.4 months, respectively. The most common grade 3 or worse adverse events were hematologic and non-hematologic toxicities were generally mild. Neutropenia, thrombocytopenia, and febrile neutropenia occurred in 28.3%, 13%, and 2.2%, respectively. Conclusions: This study demonstrates the activity of CDDP plus S-1 combination chemotherapy in patients with CUP. Updated response rate, safety data, and OS data will be presented.