Thymidine synthase, thymidine phosphorylase, and excision repair cross-complementation group 1 expression as predictive markers of capecitabine plus cisplatin chemotherapy as first-line treatment for patients with advanced oesophageal squamous cell carcinoma

BACKGROUND: Our purpose was to evaluate thymidine synthase (TS), thymidine phosphorylase (TP), and excision repair cross-complementation group 1 (ERCC1) expression as biomarkers for capecitabine and cisplatin (XP) combination chemotherapy in patients with metastatic oesophageal squamous cell cancer. METHOD: A total of 113 patients with metastatic oesophageal squamous cell cancer were treated with XP chemotherapy at the Samsung Medical Center between 2003 and 2007, of whom 72 had available clinical data and paraffin blocks for immunohistochemistry of TS, TP, and ERCC1. RESULTS: The median age of the 72 patients was 62 years. The overall response rate (RR) was 51.4%. The median progression-free survival (PFS) and overall survival (OS) were 4.2 and 12.0 months, respectively. High expression of TS and TP was associated with a higher RR than was low expression of TS and TP (54.1 vs 40.5%, P=0.022). Strong ERCC1 expression and a low TS score were identified as unfavourable independent risk factors for PFS (HR 10.71, 95% confidence interval (CI) 2.1–54.7, P=0.004 for strong ERCC1 expression; and HR 2.9, 95% CI 1.0–7.9, P=0.044 for low TS score). Strong ERCC1 expression was identified as an unfavourable independent risk factor for OS (HR 3.73, 95% CI 1.39–10.0, P=0.009). CONCLUSION: These data indicate that expression of TS, TP, and ERCC1 may be predictive markers for response and survival in patients with metastatic oesophageal squamous cell cancer receiving XP chemotherapy.