Expression of excision repair cross-complementation group 1 protein and outcome in patients with nasopharyngeal cancer

Abstract

6085 Background: We evaluated the prognostic significance of thymidylate synthase (TS), and Excision Repair Cross-Complementation Group 1 protein (ERCC1) in patients (pts) with nasopharyngeal cancer (NPC) treated with concurrent chemoradiotherapy (CCRT). Methods: Pretreatment tumor biopsy specimens from 41 pts with locally advanced NPC were analyzed for TS and ERCC1 expression by immunohistochemistry. All patients were treated with 1 cycle of induction chemotherapy (5-fluorouracil 1,000 mg/m2/day and cisplatin 20 mg/m2/day, days 1–4) followed by CCRT starting on day 22. CCRT consisted of radiotherapy (70Gy/35 fractions for 7 weeks) with cisplatin 20mg/m2/day for 4 days on weeks 1, 4, 7 of radiotherapy. Results: Complete response and partial response were achieved in 34 pts (83%) and 6 pts (15%), respectively. Within median follow up duration of 101 months (26–147months) in survivors, 5-years overall survival (OS) of all pts was 50%. High expression of TS and ERCC1 was observed in 21 (51%) and 25 (60%) pts, respectively. High expression of ERCC1 was associated with WHO type 1 or 2 histology (p = 0.045). In univariate analysis, high expression of ERCC1 was associated with poor OS (5-year: 73% versus 35%; p = 0.005), while high expression of TS was not correlated with pts outcome (p = 0.867). In multivariate analysis, high expression of ERCC1 was a significant independent predictor of poor OS (p = 0.041) along with WHO type 1 or 2 histology (p = 0.004). Conclusions: High expression of ERCC1 protein may be useful for prediction of poor outcome in pts with NPC treated with CCRT. No significant financial relationships to disclose.