Pretreatment Epstein-Barr virus DNA load and cumulative cisplatin dose intensity affect long-term outcome of nasopharyngeal carcinoma treated with concurrent chemotherapy: experience of an institute in an endemic area.

Background: We retrospectively compared the long-term efficacy of concurrent chemoradiotherapy (CCRT) regimens (docetaxel vs. cisplatin), total dose intensity of cisplatin (> 200 vs. ≤ 200 mg/m2) and pretreatment plasma levels of Epstein-Barr virus (EBV) DNA for nasopharyngeal carcinoma (NPC), and investigated the prognostic factors.

Methods: We enrolled 214 patients diagnosed with NPC and treated with CCRT. 41 patients received weekly docetaxel and 173 weekly cisplatin. 62 received cumulative cisplatin of ≤ 200 mg/m2 and 111, > 200 mg/m2. Pretreatment levels of EBV DNA were available for 155 patients.

Results: Patients receiving concurrent weekly docetaxel and cisplatin had similar 5-year rates for overall survival (OS) (p = 0.306), progression-free survival (PFS) (p = 0.133), distant failure-free survival (DFS) (p = 0.110), and locoregional failure-free survival (LFS) (p = 0.452). Cumulative cisplatin of > 200 mg/m2 improved the 5-year rates of PFS (p = 0.018) and DFS (p = 0.042) significantly in comparison with cumulative cisplatin of ≤ 200 mg/m2. EBV DNA levels of ≥ 1,500 copies/ml was closely associated with poor DFS (p = 0.011), PFS (p = 0.006), and OS (p = 0.004).

Conclusions: Weekly cisplatin was well tolerated in CCRT, during which cumulative cisplatin of > 200 mg/m2 improved PFS and DFS. The long-term efficacy of concurrent docetaxel was similar to that of concurrent cisplatin. The EBV DNA level was the most significant prognostic factor.