Combined Ki67 and ERCC1 for prognosis in non-keratinizing nasopharyngeal carcinoma underwent chemoradiotherapy

This study aimed to assess the predictive value of combined Ki67 and ERCC1 in distant metastasis-free nasopharyngeal carcinoma. 334 such cases were retrospectively assessed. Immunohistochemistry was used to evaluate Ki67 and ERCC1 protein levels in tumor tissues. Associations of Ki67 and ERCC1 amounts with clinical characteristics and survival were analyzed. Medium follow-up was 48.7 months; overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS), and local recurrence-free survival (LRFS) were 91.3%, 76.0%, 82.0%, and 91.9%, respectively. High Ki67 expression was found in 35.6% patients, and positively correlated with clinical- and N- staging (P = 0.005, P < 0.001); 4-year OS, DFS, and DMFS were significantly lower in the high Ki67 group than patients with low-medium expression (P = 0.001, P = 0.012, P = 0.007). High ERCC1 expression was found in 35.3% of patients, and positively correlated with clinical- and T- staging. Compared with low ERCC1 expression cases, 4-year OS, DFS, DMFS, and LRFS were decreased significantly in those with high levels. High Ki67 and ERCC1 levels were related to adverse prognoses of OS (HR=4.977, 95% CI 2.31-12.292, P<0.001), DFS (HR = 4.178, 95% CI 2.421-7.212, P < 0.001), DMFS (HR = 3.722, 95% CI 2.028-7.015, P < 0.001), and LRFS (HR = 3.689, 95% CI 1.423-9.566, P = 0.007). Compared with the low-medium Ki67 and low ERCC1 groups, no significant difference in survival prognosis was obtained in the low-medium Ki67 and high ERCC1 groups, and patients with high Ki67 and low ERCC1 levels. Combined Ki67 and ERCC1 can better predict nasopharyngeal carcinoma prognosis than individual parameters.