Different relation between ERCC1 overexpression and treatment outcomes of two platinum agents in advanced biliary tract adenocarcinoma patients

The aim of this study is to evaluate the effect of excision repair cross-complementation group 1 (ERCC1) expression on treatment outcomes in advanced biliary tract adenocarcinoma (ABTA) patients treated with platinum-based chemotherapy.One hundred and six patients with histologically confirmed adenocarcinoma of biliary tract were enrolled at 5 institutions in South Korea between January 2002 and September 2008. Of 106 patients, 93 were assessed by immunohistochemistry from tissue specimens. Sixty-five patients were treated with cisplatin-based regimens and the other 28 treated with oxaliplatin-based ones.For total study population, no significant differences were noted in progression-free survival (PFS) and overall survival (OS) between ERCC1-negative and ERCC1-positive patients, respectively (4.2 vs. 2.9 months, p = 0.116; 7.0 vs. 7.8 months, p = 0.143). In patients treated with cisplatin-based regimens, median PFS and OS were significantly longer in ERCC1-negative group than in ERCC1-positive group, respectively (4.6 vs. 1.9 months, p = 0.014; 9.1 vs. 7.9 months, p = 0.017). Disease control rate (DCR) was better in patients with ERCC1 negative than in patients with ERCC1 positive (p = 0.048). On the other hand, in patients treated with oxaliplatin-containing regimens, median PFS and OS tended to be longer in ERCC1-positive group, but these did not reach statistical significances. Response rate was better in patients with ERCC1 positive (p = 0.005).ERCC1 shows a significant prognostic value in ABTA patients treated with cisplatin. A survival benefit was observed in ERCC1-negative patients from cisplatin-containing chemotherapy but not from oxaliplatin-containing ones. The action mechanism of ERCC1 on cisplatin may be different from that on oxaliplatin.